An artistic medium is the substance the artistic work is made from. So for example acrylic and oil are two media common to painting.
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Masonite is a type of hardboard made of steam-cooked and pressure-molded wood fibers in a process invented by William H. Mason. In Africa, this product is also known as Isorel,, hernit, karlit, torex or treetex.
Masonite was invented in 1924 in Laurel, Mississippi, by William H. Mason, who was a friend and protégé of inventor Thomas Edison. Mass production started in 1929. In the 1930s and 1940s Masonite was used for many applications including doors, roofing, walls, desktops, and canoes. It was sometimes used for house siding.
Similar "tempered hardboard" is now a generic product made by many forest product companies. The Masonite Corporation entered the door business as a supplier of facings in 1972, and was purchased in 2001 by Premdor Corporation, a door maker, from its former parent International Paper; it no longer supplies generic hardboard.
Masonite is formed using the Mason method, in which wood chips are disintegrated by saturating them with 100psi steam, then increasing the steam or air pressure to 400psi and suddenly releasing them through an orifice to atmospheric pressure. Forming the fibers into boards on a screen, the boards are then pressed and heated to form the
Terracotta, Terra cotta or Terra-cotta (Italian: "baked earth", from the Latin terra cotta), a type of earthenware, is a clay-based unglazed or glazed ceramic, where the fired body is porous. Its uses include vessels (notably flower pots), water and waste water pipes, bricks, and surface embellishment in building construction, along with sculpture such as the Terracotta Army and Greek terracotta figurines. The term is also used to refer to items made out of this material and to its natural, brownish orange color, which varies considerably. In archaeology and art history, "terracotta" is often used of objects not made on a potter's wheel, such as figurines, where objects made on the wheel from the same material, possibly even by the same person, are called pottery; the choice of term depending on the type of object rather than the material.
An appropriate refined clay is shaped into the desired shape. After drying it is placed in a kiln, or atop combustible material in a pit, and then fired. The typical firing temperatures is around 1000°C. The iron content gives the fired body a yellow, orange, red, "terracotta", pink, grey or brown color. Fired terracotta is not watertight, but
A tondo (plural "tondi" or "tondos") is a Renaissance term for a circular work of art, either a painting or a sculpture. The word derives from the Italian rotondo, "round." The term is usually not used in English for small round paintings, but only those over about 60 cm (two feet) in diameter, thus excluding many round portrait miniatures – for sculpture the threshold is rather lower.
Artists have created tondi since Greek antiquity. The circular paintings in the centre of painted vases of that period are known as tondi, and the inside of the broad low winecup called a kylix also lent itself to circular enframed compositions. The style was revived in in the fifteenth and sixteenth centuries, particularly in Italy. Since then it has been less common. In Ford Madox Brown's painting The Last of England, the ship's wire railing curving round the figures helps enclose the composition within its tondo shape.
The background scene is consolidated or omitted, and to a large extent, unimportant. While the background may be visible in tondo paintings, in tondo relief carvings the background is not seen. Andrea della Robbia and other members of his family created glazed terracotta tondi that
Newsprint is a low-cost, non-archival paper most commonly used to print newspapers, and other publications and advertising material. It usually has an off-white cast and distinctive feel. It is designed for use in printing presses that employ a long web of paper (web offset, letterpress and flexographic) rather than individual sheets of paper. Newsprint mainly consists of wood pulp.
Newsprint is favored by publishers and printers for its combination of being relatively low cost (compared with paper grades used to print such products as glossy magazines or sales brochures), high strength (to run through modern high-speed web printing presses) and the ability to accept four-color printing at qualities that meet the needs of typical newspaper advertisers.
The web of paper is placed on the press in the form of a roll delivered from a paper mill (surplus newsprint can also be cut into individual sheets by a processor for use in a variety of other applications such as wrapping or commercial printing). World demand of newsprint in 2006 totaled about 37.2 million metric tonnes, according to the Montreal-based Pulp & Paper Products Council (PPPC). This was about 1.6% less than in 2000.
Pistacia lentiscus (Greek: μαστίχα) (Mastic) is a dioecious evergreen shrub or small tree of the Pistacio genus growing up to 4 m (13 ft) tall which is cultivated for its aromatic resin, mainly on the Greek island of Chios.
This is a shrub or tree dioecious, with separate male and female plants, evergreen from 1 to 5 m high, with a strong smell of resin, which grows in the dry and rocky areas in Mediterranean Europe. It resists heavy frosts and grows on all types of soils and can grow well in limestone areas and even salty or saline, this makes it more abundant near the sea. It is also found in woodlands, dehesas (almost deforested pasture areas), kermes oak wood, oaks wood, garrigue, maquis, hills, gorges, canyons and rocky hillsides of the entire Mediterranean area. It is a very typical species that grows in Mediterranean mixed communities of myrtle, Kermes oak, Mediterranean dwarf Palm, buckthorn, sarsaparilla, etc. and serves as protection and food for birds and other fauna in this ecosystem. It is a very hardy pioneer species dispersed by birds and abundant in dry Mediterranean. When older, it develops some large trunks and numerous thicker and longer branches. In appropriate
Zinc chromate, ZnCrO4, is a chemical compound containing the chromate anion, appearing as odorless yellow solid powder. It is used industrially in chromate conversion coatings, having been developed by Ford Motor Company in 1920s. Exposure to zinc chromate can cause tissue ulceration and cancer.
Its use as a corrosion resistant agent was applied to aluminium alloy parts first in commercial aircraft, and then in military ones. During the 1940 and 1950s it was typically found as the "paint" in the wheel wells of retractable landing gear on U.S. military aircraft, not because of its glaring yellow-green color symbolizing anything, but to protect the aluminium from corrosion.
When used as a pigment, it is known as Zinc Yellow, Buttercup Yellow or Yellow 36. It is rarely used in art anymore.
Zinc chromate putty was used as sealant in addition to two O-rings between sections of the failed solid rocket booster on Space Shuttle Challenger, contributing to the loss of the shuttle.
Lusterware or Lustreware (respectively the US and all other English spellings) is a type of pottery or porcelain with a metallic glaze that gives the effect of iridescence, produced by metallic oxides in an overglaze finish, which is given a second firing at a lower temperature in a "muffle kiln", reduction kiln, which excludes oxygen.
The first use of lustre decoration was as painting on glass. While some scholars see this as a purely Islamic invention originating in Fustat, others place the origins of lustre decoration in Roman and Coptic Egypt during the centuries preceding the rise of Islam. Staining glass vessels with copper and silver pigments was known from around the 3rd century AD, although true lustre technology probably began sometime between the 4th and 8th centuries AD.
Lustre glazes were applied to pottery in Mesopotamia in the 9th century; the technique soon became popular in Persia and Syria. In the Mosque of Uqba also known as the Great Mosque of kairouan (in Tunisia), the upper part of the mihrab is adorned with polychrome and monochrome lusterware tiles; dating from 862-863, these tiles were most probably imported from Mesopotamia. Lusterware was later produced
Monoprinting is a form of printmaking that has images or lines that can only be made once, unlike most printmaking, where there are multiple originals. There are many techniques of monoprinting. Examples of standard printmaking techniques which can be used to make monoprints include lithography, woodcut, and etching.
A monoprint is a single impression of an image made from a reprintable block, such as a metal plate used for etching, a litho stone or wood block. Rather than printing an edition of multiple copies of a single image, only one impression may be produced, either by painting or making a collage on the block. Etching plates may also be inked in a way that is expressive and unique in the strict sense, in that the image cannot be reproduced exactly. Monoprints may also involve elements that change, where the artist reworks the image in between impressions or after printing so that no two prints are absolutely identical. Monoprints may include collage, hand-painted additions, and a form of tracing by which thick ink is laid down on a table, paper is placed on top and is then drawn on, transferring the ink onto the paper. Monoprints can also be made by altering the type,
The albumen print, also called albumen silver print, was invented in 1850 by Louis Désiré Blanquart-Evrard, and was the first commercially exploitable method of producing a photographic print on a paper base from a negative. It used the albumen found in egg whites to bind the photographic chemicals to the paper and became the dominant form of photographic positives from 1855 to the turn of the 20th century, with a peak in the 1860-90 period. During the mid-19th century, the carte de visite became one of the more popular uses of the albumen method. In the 19th century, E. & H. T. Anthony & Company were the largest makers and distributors of the Albumen photographic prints and paper in the United States.
Because the image emerges as a direct result of exposure to light, without the aid of a developing solution, an albumen print may be said to be a printed rather than a developed photograph.
The table salt (sodium chloride) in the albumen emulsion forms silver chloride when in contact with silver nitrate. Silver chloride is unstable when exposed to light, which makes it decompose into silver and chlorine. The silver ion (Ag+) is reduced to silver (Ag) by addition of an electron during
Gouache(/ɡuːˈæʃ/; French: [ˈɡwaʃ]), also spelled guache, is a type of paint consisting of pigment, a binding agent (usually gum arabic), and sometimes added inert material, designed to be used in an opaque method. It also refers to paintings that use this opaque method. The name derives from the Italian guazzo, and is also referred to as opaque watercolor or bodycolor (the term preferred by art historians).
Gouache paint is similar to watercolor but modified to make it an opaque painting medium (non-transparent). A binding agent, usually gum arabic, is present, just as in watercolor. Gouache differs from watercolor in that the particles are larger, the ratio of pigment to water is much higher, and an additional, inert, white pigment such as chalk is also present. This makes gouache heavier and more opaque, with greater reflective qualities. Gouache generally dries to a different value than it appears when wet (lighter tones generally dry darker, while darker tones tend to dry lighter), which can make it difficult to match colors over multiple painting sessions. Its quick coverage and total hiding power mean that gouache lends itself to more direct painting techniques than
Tempera, also known as egg tempera, is a permanent fast-drying painting medium consisting of colored pigment mixed with a water-soluble binder medium (usually a glutinous material such as egg yolk or some other size). Tempera also refers to the paintings done in this medium. Tempera paintings are very long lasting, and examples from the 1st centuries CE still exist. Egg tempera was a primary method of painting until after 1500 when it was superseded by the invention of oil painting. A paint consisting of pigment and glue size commonly used in America as poster paint is also often referred to as "tempera paint," although the binders and sizes in this paint are different from traditional tempera paint.
Tempera painting has been found on early Egyptians sarcophagi decorations. Many of the Fayum mummy portraits use tempera, sometimes in combination with encaustic.
A related technique has been used also in ancient and early medieval paintings found in several caves and rock-cut temples of India. High-quality art with the help of tempera was created in Bagh Caves between the late 4th and 10th centuries CE and in the 7th century CE in Ravan Chhaya rock shelter, Orissa.
The art technique
Glass brick, also known as glass block, is an architectural element made from glass. Glass bricks provide visual obscuration while admitting light. The glass block was originally developed in the early 1900s to provide natural light in industrial factories. Glass bricks are produced for both wall and floor applications. Floors Glass blocks for use in floors are normally manufactured as a single solid piece, or as a hollow glass block with thicker side walls than the standard wall blocks.
Glass blocks for floors are normally cast into a reinforced concrete grid work or set into a metal frame, allowing multiple units to be combined to span over openings in basements and roofs. Walls Glass wall blocks should not be used in flooring applications. Hollow glass wall blocks are manufactured as two separate hemispheres and, whilst the glass is still molten, the two hemispheres are pressed together and annealed. The resulting glass blocks will have a partial vacuum at the hollow centre.
Specialist glass blocks are produced for various applications including:-
Bullet and vandal resisting; these blocks are generally solid glass or have very thick side walls similar to pavement blocks.
A metal (from Greek "μέταλλον" – métallon, "mine, quarry, metal") is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable, ductile and shiny. The meaning of the term "metal" differs for various communities. Many elements and compounds that are not normally classified as metals become metallic under high pressures (see nonmetal#Metallic allotropes.)
Metals typically consist of close-packed atoms, meaning that the atoms are arranged like closely packed spheres. Two packing motifs are common, one being body-centered cubic wherein each metal is surrounded by eight equivalent metals. The other main motif is face-centered cubic where the metals are surrounded by six neighboring atoms. Several metals adopt both structures, depending on the temperature.
In a metal, atoms readily lose electrons to form positive ions (cations). Those ions are surrounded by de-localized electrons, which are responsible for the conductivity. The solid thus produced is held together by electrostatic interactions between the ions and the electron cloud, which are called metallic bonds.
Metals are usually inclined to form cations through electron loss,
Nylon is a generic designation for a family of synthetic polymers known generically as polyamides, first produced on February 28, 1935, by Wallace Carothers at DuPont's research facility at the DuPont Experimental Station. Nylon is one of the most commonly used polymers.
Nylon is a thermoplastic, silky material, first used commercially in a nylon-bristled toothbrush (1938), followed more famously by women's stockings ("nylons"; 1940). Nylon is made of repeating units linked by amide bonds and is frequently referred to as polyamide (PA). Nylon was the first commercially successful synthetic polymer. There are two common methods of making nylon for fiber applications. In one approach, molecules with an acid (-COOH) group on each end are reacted with molecules containing amine (-NH2) groups on each end. The resulting nylon is named on the basis of the number of carbon atoms separating the two acid groups and the two amines. These are formed into monomers of intermediate molecular weight, which are then reacted to form long polymer chains.
Nylon was intended to be a synthetic replacement for silk and substituted for it in many different products after silk became scarce during World
An oak is a tree or shrub in the genus Quercus ( /ˈkwɜrkəs/; Latin "oak tree"), of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus. The genus is native to the Northern Hemisphere, and includes deciduous and evergreen species extending from cool temperate to tropical latitudes in Asia and the Americas.
Oaks have spirally arranged leaves, with lobed margins in many species; some have serrated leaves or entire leaves with smooth margins. Many deciduous species are marcescent, not dropping dead leaves until spring. The flowers are catkins, produced in spring. The fruit is a nut called an acorn, borne in a cup-like structure known as a cupule; each acorn contains one seed (rarely two or three) and takes 6–18 months to mature, depending on species. The live oaks are distinguished for being evergreen, but are not actually a distinct group and instead are dispersed across the genus.
Oak trees are a flowering plant. The genus is divided into two subgenera and a number of sections:
The subgenus Quercus is divided into the following sections:
There are also some rare species of oak trees which are widely unknown: Scarlet Oak
Faience or faïence (/faɪˈɒ̃s/ or /feɪˈɑːns/, French: [fajɑ̃s]) is the conventional name in English for fine tin-glazed pottery on a delicate pale buff earthenware body, originally associated with Faenza in northern Italy. The invention of a white pottery glaze suitable for painted decoration, by the addition of an oxide of tin to the slip of a lead glaze, was a major advance in the history of pottery. The invention seems to have been made in Iran or the Middle East before the ninth century. A kiln capable of producing temperatures exceeding 1,000 °C (1,830 °F) was required to achieve this result (see pottery), the result of millennia of refined pottery-making traditions. The term is now used for a wide variety of pottery from several parts of the world, including many types of European painted wares, often produced as cheaper versions of porcelain styles.
Technically, lead-glazed earthenware, such as the French sixteenth-century Saint-Porchaire ware, does not properly qualify as faience, but the distinction is not usually maintained.
The term "faience" has been extended to include finely glazed ceramic beads found in Egypt as early as 4000 BC and in the Indus Valley Civilization.
Handmade Paper making is an art of making paper using cotton fabric,waste paper and other plant fibers into exquisite sheets of paper. This is a traditional craft still practiced in many parts of India, Nepal, China and other South East Asian countries.The art of handmade paper is still practiced in many parts of India by the community called' Kagzis'.
There are various type of handmade paper based on the various material used and the treatment given to them resulting varied textures
Handmade paper is given exquisite looks by various type of treatment
All handmade paper look beautiful and can be brought to different type of usages
Finally this paper gives you the feeling that at least you are contributing in some way to save our environment.This paper is also biodegradable. Therefore using handmade paper is the only best and easiest way to protect environment.
There are many good companies manufacturing and supplying handmade paper. Some of the good sites are
Chrome steel is one of a class of non stainless steels such as AISI 52100, En31, SUJ2, 100Cr6, 100C6, DIN 5401 which are used for applications such bearings, tools and drills.
The term was used in both the original 1933 version, as well as the 2005 remake, of King Kong. When Kong is brought to New York, he is chained with this metal on stage. The impression given by the movie from Carl Denham to the audience is that the "chrome steel" has some unique properties of having a higher tensile strength than "normal steel" which is incorrect. The chromium component of chrome steel would only provide some corrosion resistance. Higher tensile strength steels are created by the addition of carbon. True to this deceptive description, Kong breaks free anyway.
The term was also used in the Star Trek episode "A Private Little War," where the guns introduced to the primitive villagers by the Klingons were fashioned with a chrome steel drill point.
Granite ( /ˈɡrænɨt/) is a common widely occurring type of intrusive, felsic, igneous rock which is granular and crystalline in texture. This rock consists mainly of quartz, mica, and feldspar. Occasionally some individual crystals (phenocrysts) are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic texture is sometimes known as a porphyry. Granites can be pink to gray in color, depending on their chemistry and mineralogy. By definition, granite is an igneous rock with at least 20% quartz by volume. Granite differs from granodiorite in that at least 35% of the feldspar in granite is alkali feldspar as opposed to plagioclase; it is the alkali feldspar that gives many granites a distinctive pink color. Outcrops of granite tend to form tors and rounded massifs. Granites sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole or hornfels. Granite is usually found in the continental plates of the Earth's crust.
Granite is nearly always massive (lacking internal structures), hard and tough, and therefore it has gained widespread use as a construction stone. The average density
Soapstone (also known as steatite or soaprock) is a metamorphic rock, a talc-schist. It is largely composed of the mineral talc and is thus rich in magnesium. It is produced by dynamothermal metamorphism and metasomatism, which occurs in the areas where tectonic plates are subducted, changing rocks by heat and pressure, with influx of fluids, but without melting. It has been a medium for carving for thousands of years.
Petrologically, soapstone is composed dominantly of talc, with varying amounts of chlorite and amphiboles (typically tremolite, anthophyllite, and magnesiocummingtonite), and trace to minor FeCr-oxides. It may be schistose or massive. Soapstone is formed by the metamorphism of ultramafic protoliths (e.g. dunite or serpentinite) and the metasomatism of siliceous dolostones.
Pyrophyllite, a mineral very similar to talc, is sometimes called soapstone in the generic sense since its physical characteristics and industrial uses are similar, and because it is also commonly used as a carving material. However this mineral typically does not have such a soapy feel as that from which soapstone derives its name.
Steatite is relatively soft (because of the high talc content,
A textile or cloth is a flexible woven material consisting of a network of natural or artificial fibres often referred to as thread or yarn. Yarn is produced by spinning raw fibres of wool, flax, cotton, or other material to produce long strands. Textiles are formed by weaving, knitting, crocheting, knotting, or pressing fibres together (felt).
The words fabric and cloth are used in textile assembly trades (such as tailoring and dressmaking) as synonyms for textile. However, there are subtle differences in these terms in specialized usage. Textile refers to any material made of interlacing fibres. Fabric refers to any material made through weaving, knitting, spreading, crocheting, or bonding that may be used in production of further goods (garments, etc.). Cloth may be used synonymously with fabric but often refers to a finished piece of fabric used for a specific purpose (e.g., table cloth).
The word textile is from Latin, from neuter of textilis, woven, from textus, past participle of texere, to weave; see text.
The discovery of dyed flax fibres in a cave in the Republic of Georgia dated to 34,000 BCE suggests textile-like materials were made even in prehistoric times.
Neoprene or polychloroprene is a family of synthetic rubbers that are produced by polymerization of chloroprene. Neoprene exhibits good chemical stability, and maintains flexibility over a wide temperature range. It is used in a wide variety of applications, such as laptop sleeves, orthopedic braces (wrist, knee, etc.), electrical insulation, liquid and sheet applied elastomeric membranes or flashings, and automotive fan belts.
Neoprene is produced by free-radical polymerization of 2-chlorobutadiene. The polymerization is conducted in an aqueous emulsion, using diverse emulsifying agents such as alkyl sulfonates. Outside of Russia and China, about 300,000 tons of neoprene are produced annually.
Neoprene was invented by DuPont scientists on April 17, 1930 after Dr Elmer K. Bolton of DuPont laboratories attended a lecture by Fr Julius Arthur Nieuwland, a professor of chemistry at the University of Notre Dame. Fr. Nieuwland's research was focused on acetylene chemistry and during the course of his work he produced divinyl acetylene, a jelly that firms into an elastic compound similar to rubber when passed over sulfur dichloride. After DuPont purchased the patent rights from the
Artworks:DeSoto, Wisconsin, from the album Views of the Mississippi River
Cyanotype is a photographic printing process that gives a cyan-blue print. The process was popular in engineering circles well into the 20th century. The simple and low-cost process enabled them to produce large-scale copies of their work, referred to as blueprints. Two chemicals are used in the process:
The English scientist and astronomer Sir John Herschel discovered this procedure in 1842. Though the process was developed by Herschel, he considered it as mainly a means of reproducing notes and diagrams, as in blueprints. It was Anna Atkins who brought this to photography. She created a limited series of cyanotype books that documented ferns and other plant life from her extensive seaweed collection. Atkins placed specimens directly onto coated paper, allowing the action of light to create a sillhouette effect. By using this photogram process, Anna Atkins is regarded as the first female photographer.
In a typical procedure, equal volumes of an 8.1% (w/v) solution of potassium ferricyanide and a 20% solution of ferric ammonium citrate are mixed. This mildly photosensitive solution is then applied to a receptive surface (such as paper or cloth) and allowed to dry in a dark place.
Titanium ( /taɪˈteɪniəm/ ty-TAY-nee-əm) is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant (including sea water, aqua regia and chlorine) transition metal with a silver color.
Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791 and named by Martin Heinrich Klaproth for the Titans of Greek mythology. The element occurs within a number of mineral deposits, principally rutile and ilmenite, which are widely distributed in the Earth's crust and lithosphere, and it is found in almost all living things, rocks, water bodies, and soils. The metal is extracted from its principal mineral ores via the Kroll process or the Hunter process. Its most common compound, titanium dioxide, is a popular photocatalyst and is used in the manufacture of white pigments. Other compounds include titanium tetrachloride (TiCl4), a component of smoke screens and catalysts; and titanium trichloride (TiCl3), which is used as a catalyst in the production of polypropylene.
Titanium can be alloyed with iron, aluminium, vanadium, molybdenum, among other elements, to produce strong lightweight alloys for aerospace
Sanguine or red chalk is chalk of a reddish-brown colour, so called because it resembles the colour of dried blood. It has been popular for centuries for drawing (where white chalk only works on coloured paper), and the term also describes a drawing done in sanguine. The word comes via French from the Italian sanguigna.
Sanguine ( /ˈsæŋɡwɪn/) lends itself naturally to sketches, life drawings, and rustic scenes. It is ideal for rendering modeling and volume, and human flesh. In the form of wood-cased pencils and manufactured sticks, sanguine may be used similarly to charcoal and pastel. As with pastel, a mid-toned paper may be put to good use. A fixative may be applied to preserve the finished state of the drawing. Sanguine is also a family of pigments of red earth shades (where it takes the origin of its name in French). Sanguines are also available in several other tones such as orange, tan, brown, beige.
Artworks:Transvaal House, Halfway House, Transvaal, South Africa House Plan
Ink is a liquid or paste that contains pigments or dyes and is used to color a surface to produce an image, text, or design. Ink is used for drawing or writing with a pen, brush, or quill. Thicker inks, in paste form, are used extensively in letterpress and lithographic printing.
Ink can be a complex medium, composed of solvents, pigments, dyes, resins, lubricants, solubilizers, surfactants, particulate matter, fluorescers, and other materials. The components of inks serve many purposes; the ink’s carrier, colorants, and other additives control flow and thickness of the ink and its appearance when dry.
Ink formulas vary, but commonly involve four components:
Inks generally fall into four classes:
Pigment inks are used more frequently than dyes because they are more color-fast, but they are also more expensive, less consistent in color, and have less of a color range than dyes.
Pigments are solid, opaque particles suspended in ink to provide color. they can also provide gloss, abrasiveness and resistance to attack by light, heat, solvents etc. Special pigments known as extenders and opacifiers are also used. Extenders are transparent pigments which make the colors of other pigments
Onyx is a banded variety of chalcedony. The colors of its bands range from white to almost every color (save some shades, such as purple or blue). Commonly, specimens of onyx contain bands of black and/or white.
Onyx comes through Latin (of the same spelling), from the Greek ὄνυξ, meaning "claw" or "fingernail". With its fleshtone color, onyx can be said to resemble a fingernail. The English word "nail" is cognate with the Greek word.
Onyx is formed of bands of chalcedony in alternating colors. It is cryptocrystalline, consisting of fine intergrowths of the silica minerals quartz and moganite. Its bands are parallel to one another, as opposed to the more chaotic banding that often occurs in agates.
Sardonyx is a variant in which the colored bands are sard (shades of red) rather than black. Black onyx is perhaps the most famous variety, but is not as common as onyx with colored bands. Artificial treatments have been used since ancient times to produce both the black color in "black onyx" and the reds and yellows in sardonyx. Most "black onyx" on the market is artificially colored.
The name has sometimes been used, incorrectly, to label other banded lapidary materials, such as banded
The daguerreotype /dəˈɡɛrətaɪp/ (French: daguerréotype) was the first commercially successful photographic process. The image is a direct positive made in the camera on a silvered copper plate. The raw material for plates was called Sheffield plate, plating by fusion or cold-rolled cladding and was a standard hardware item produced by heating and rolling silver foil in contact with a copper support. The surface of a daguerreotype is like a mirror, with the image made directly on the silvered surface; it is very fragile and can be rubbed off with a finger, and the finished plate has to be angled so as to reflect some dark surface in order to view the image properly. Depending on the angle viewed, and the color of the surface reflected into it, the image can change from a positive to a negative.
The very first daguerreotypes used Chevalier lenses that were "slow", and the light sensitive material was silver iodide made by fuming the plate with iodine vapor. This meant that the exposure in the camera was too long to conveniently take portraits, and the first subjects taken were street scenes and architectural studies. When Petzval lenses were introduced, with lenses of a larger
A walnut is an edible seed of any tree of the genus Juglans, especially the Persian walnut, Juglans regia. Broken nutmeats of the eastern black walnut, from the tree Juglans nigra, are also commercially available in small quantities, as are foods prepared with butternut nutmeats.
Walnut seeds are a high density source of nutrients, particularly proteins and essential fatty acids. Walnuts, like other tree nuts, must be processed and stored properly. Poor storage makes walnuts susceptible to insect and fungal mold infestations; the latter produces aflatoxin - a potent carcinogen. A mold infested walnut seed batch should not be screened then consumed; the entire batch should be discarded.
Walnuts are rounded, single-seeded stone fruits of the walnut tree. The walnut fruit is enclosed in a green, leathery, fleshy husk. This husk is inedible. After harvest, the removal of the husk reveals the wrinkly walnut shell, which is in two halves. This shell is hard and encloses the kernel, which is also made up of two halves separated by a partition. The seed kernels - commonly available as shelled walnuts - are enclosed in a brown seed coat which contains antioxidants. The antioxidants protect
A crayon ( /ˈkreɪ.ɒn/, /ˈkreɪ.ən/, or US /ˈkræn/) is a stick of colored wax, charcoal, chalk, or other materials used for writing, coloring, drawing, and other methods of illustration. A crayon made of oiled chalk is called an oil pastel; when made of pigment with a dry binder, it is simply a pastel; both are popular media for color artwork. A grease pencil or china marker (UK chinagraph pencil) is made of colored hardened grease and is useful for marking on hard, glossy surfaces such as porcelain or glass. Some fine arts companies such as Swiss Caran d'Ache manufacture water-soluble crayons, whose colors are easily mixed once applied to media.
They are easy to work with, not messy (as paint and markers are), blunt (removing the risk of sharp points present when using a pencil or pen), non-toxic, very inexpensive, and available in a wide variety of colors.
Crayons are made mostly of petroleum paraffin wax. Paraffin wax is heated and cooled to achieve the correct temperature in which a usable wax substance can be dyed and then manufactured for use around the world. Paraffin waxes are used for cosmetics, candles, for the preparation of printing ink, fruit preserving, in the
Chine-collé is a special technique in printmaking, in which the image is transferred to a surface that is bonded to a heavier support in the printing process. One purpose is to allow the printmaker to print on a much more delicate surface, such as Japanese paper or linen, which pulls finer details off the plate. Another purpose is to provide a background colour behind the image that is different from the surrounding backing sheet.
The final image will depend on the design and ink color of the printed image, the color and opacity of the paper to which the image is directly printed (plus any inclusions such as petals or fibers in that paper), and the color of the backing sheet.
In the typical "direct print" method, the plate is inked, the thin paper (dampened) is placed on the inked plate and trimmed to size, paste is applied to the thin paper, and the ensemble (plate plus thin paper with paste) is placed on a dampened backing sheet. This is then run through a printing press. In the pressure of the press, the ink is transferred to the thin paper, and the thinner paper is simultaneously adhered to the backing paper. An advantage of this method is that the thin paper will be exactly
Sticker art (also known as sticker bombing, "sticker slapping", slap tagging, and sticker tagging ) is a form of street art in which an image or message is publicly displayed using stickers. These stickers may promote a political agenda, comment on a policy or issue, or comprise a subcategory of Graffiti.
Stickers can be placed anywhere accessible, with a much lower risk of apprehension by officials enforcing anti–vandalism laws.
Sticker artists use a variety of label types, including inexpensively purchased and free stickers, such as — respectively — the United States Postal Service's Label 228 or name tags. Label 228's are often used with hand-drawn art, and are quite hard to remove, leaving a white, sticky residue.
Sticker artists can design and print thousands of stickers at low cost using a commercial printing service or at home with a computer printer and self-adhesive labels.
Sticker artists also print their designs onto adhesive vinyl, which has an aggressive permanent adhesive, is waterproof, and generally fade resistant. A variant type of adhesive vinyl, called “destructible”, is used by some artists. Destructible vinyl decals are primarily used as tamper indicators on
Porcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to temperatures between 1,200 °C (2,192 °F) and 1,400 °C (2,552 °F). The toughness, strength, and translucence of porcelain arise mainly from the formation of glass and the mineral mullite within the fired body at these high temperatures.
Porcelain derives its present name from old Italian porcellana (cowrie shell) because of its resemblance to the translucent surface of the shell. Porcelain can informally be referred to as "china" or "fine china" in some English-speaking countries, as China was the birthplace of porcelain making. Properties associated with porcelain include low permeability and elasticity; considerable strength, hardness, toughness, whiteness, translucency and resonance; and a high resistance to chemical attack and thermal shock.
For the purposes of trade, the Combined Nomenclature of the European Communities defines porcelain as being "completely vitrified, hard, impermeable (even before glazing), white or artificially coloured, translucent (except when of considerable thickness), and resonant." However, the term porcelain lacks a universal
The World Wide Web (abbreviated as WWW or W3, commonly known as the Web), is a system of interlinked hypertext documents accessed via the Internet. With a web browser, one can view web pages that may contain text, images, videos, and other multimedia, and navigate between them via hyperlinks.
Using concepts from his earlier hypertext systems like ENQUIRE, British engineer, computer scientist and at that time employee of CERN, Sir Tim Berners-Lee, now Director of the World Wide Web Consortium (W3C), wrote a proposal in March 1989 for what would eventually become the World Wide Web. At CERN, a European research organization near Geneva situated on Swiss and French soil, Berners-Lee and Belgian computer scientist Robert Cailliau proposed in 1990 to use hypertext "to link and access information of various kinds as a web of nodes in which the user can browse at will", and they publicly introduced the project in December of the same year.
In the May 1970 issue of Popular Science magazine, Arthur C. Clarke predicted that satellites would someday "bring the accumulated knowledge of the world to your fingertips" using a console that would combine the functionality of the Xerox, telephone,
A carbon print is a photographic print with an image consisting of pigmented gelatin, rather than of silver or other metallic particles suspended in a uniform layer of gelatin, as in typical black-and-white prints, or of chromogenic dyes, as in typical photographic color prints.
In the original version of the printing process, carbon tissue (a temporary support sheet coated with a layer of gelatin mixed with a pigment—originally carbon black, from which the name derives) is bathed in a potassium dichromate sensitizing solution, dried, then exposed to strong ultraviolet light through a photographic negative, hardening the gelatin in proportion to the amount of light reaching it. The tissue is then developed by treatment with warm water, which dissolves the unhardened gelatin. The resulting pigment image is physically transferred to a final support surface, either directly or indirectly. In an important early 20th century variation of the process, contact with a conventional silver bromide paper print, rather than exposure to light, was used to selectively harden the gelatin. A wide variety of colored pigments can be used instead of carbon black.
The process can produce images of
Chiffon, French pronunciation: [ʃi.fɔ̃], from the French word for a cloth or rag, is a lightweight, balanced plain-woven sheer fabric woven of alternate S- and Z-twist crepe (high-twist) yarns. The twist in the crepe yarns puckers the fabric slightly in both directions after weaving, giving it some stretch and a slightly rough feel.
Chiffon is made from cotton, silk or synthetic fibres. Chiffon can be dyed to almost any shade, but chiffon made from polyester can be difficult to dye. Under a magnifying glass it resembles a fine net or mesh which gives chiffon some see-through properties.
When sewing chiffon, many crafters layer tissue paper in between the two pieces being sewn together. The tissue paper helps keep the fabric together, with the rough surface of the tissue holding the chiffon in place while it is handled. After sewing, the tissue paper can be carefully ripped out. Chiffon is also pinnable, as it will spring back, concealing pin marks. As a general rule, sewers should work slowly and steadily with this fabric, taking care not to run it through a sewing machine too quickly or it will bunch and gather.
Chiffon is most commonly used in evening wear, especially as an
Fiberglass (or fibreglass) (also called glass-reinforced plastic, GRP, glass-fiber reinforced plastic, or GFRP), is a fiber reinforced polymer made of a plastic matrix reinforced by fine fibers of glass. It is also known as GFK (for German: Glasfaserverstärkter Kunststoff).
Fiberglass is a lightweight, extremely strong, and robust material. Although strength properties are somewhat lower than carbon fiber and it is less stiff, the material is typically far less brittle, and the raw materials are much less expensive. Its bulk strength and weight properties are also very favorable when compared to metals, and it can be easily formed using molding processes.
The plastic matrix may be epoxy, a thermosetting plastic (most often polyester or vinylester) or thermoplastic.
Common uses of fiberglass include boats, automobiles, baths, hot tubs, water tanks, roofing, pipes, cladding, casts and external door skins.
Unlike glass fibers used for insulation, for the final structure to be strong, the fiber's surfaces must be almost entirely free of defects, as this permits the fibers to reach gigapascal tensile strengths. If a bulk piece of glass were to be defect free, then it would be equally as
Sheet metal is simply metal formed into thin and flat pieces. It is one of the fundamental forms used in metalworking, and can be cut and bent into a variety of different shapes. Countless everyday objects are constructed of the material. Thicknesses can vary significantly, although extremely thin thicknesses are considered foil or leaf, and pieces thicker than 6 mm (0.25 in) are considered plate.
Sheet metal is available in flat pieces or as a coiled strip. The coils are formed by running a continuous sheet of metal through a roll slitter.
The thickness of the sheet metal is called its gauge. Commonly used steel sheet metal ranges from 30 gauge to about 8 gauge. The larger the gauge number, the thinner the metal. Gauge is measured in ferrous (iron based) metals while nonferrous metals such as aluminum or copper are designated differently; i.e. Copper is measured in thickness by Ounce.
There are many different metals that can be made into sheet metal, such as aluminum, brass, copper, steel, tin, nickel and titanium. For decorative uses, important sheet metals include silver, gold, and platinum (platinum sheet metal is also utilized as a catalyst.)
Sheet metal also has applications
Naugahyde (sometimes abbreviated to Nauga) is an American brand of artificial leather ("pleather"). Naugahyde is a composite of a knit fabric backing and polyvinyl chloride (PVC) plastic coating. It was developed by United States Rubber Company, and is now manufactured and sold by the Uniroyal Engineered Products division of Michelin. Its name, first used as a trademark in 1936, comes from the Borough of Naugatuck, Connecticut, where it was first produced. Uniroyal asserts that Naugahyde is one of the most popular premium pleathers. Naugahyde is manufactured in Stoughton, Wisconsin.
A marketing campaign of the 1960s and 1970s asserted humorously that Naugahyde was obtained from the skin of an animal called a "Nauga". The claim became an urban myth. The campaign emphasized that, unlike other animals, which must typically be slaughtered to obtain their hides, Naugas can shed their skin without harm to themselves. The Nauga doll, a squat, horned monster with a wide toothy grin, became popular in the 1960s and is still sold today.
Artworks:Francisque Sarcey from the publication Galerie Contemporaine
The term Woodburytype refers to both a photomechanical process and the print produced by this process. The process produces continuous tone images in slight relief. A chromated gelatin film is exposed under a photographic negative, which hardens in proportion to the amount of light. Then it is developed in hot water to remove all the unexposed gelatin and dried. This relief is pressed into a sheet of lead in a press with 5000 psi. This is an intaglio plate. It is used as a mold and is filled with pigmented gelatin. The gelatin layer is then pressed onto a paper support.
The Woodburytype was developed by Walter B. Woodbury in 1864, first used in a publication in 1866 and widely used for fine book illustration from about 1870 to 1900. It was the only commercially successful method for producing illustration material capable of replicating the subtleties and details of a photograph. It is the only mechanical printing method ever invented which produces true middle values and does not make use of a screen or other image deconstruction method.
Artists' books are works of art realized in the form of a book. They are often published in small editions, though sometimes they are produced as one-of-a-kind objects referred to as "uniques".
Artists' books have employed a wide range of forms, including scrolls, fold-outs, concertinas or loose items contained in a box as well as bound printed sheet. Artists have been active in printing and book production for centuries, but the artist's book is primarily a late 20th century form.
"Artists' books are books or book-like objects over the final appearance of which an artist has had a high degree of control; where the book is intended as a work of art in itself." Stephen Bury
Whilst artists have been involved in the production of books in Europe since the early medieval period (such as the Book of Kells and the Très Riches Heures du Duc de Berry), most writers on the subject cite the English visionary artist and poet William Blake (1757–1827) as the earliest direct antecedent
Books such as Songs of Innocence and of Experience were written, illustrated, printed, coloured and bound by Blake and his wife Catherine, and the merging of handwritten texts and images created intensely vivid,
Photogravure is an intaglio printmaking or photo-mechanical process whereby a copper plate is coated with a light-sensitive gelatin tissue which had been exposed to a film positive, and then etched, resulting in a high quality intaglio print that can reproduce the detail and continuous tones of a photograph.
The earliest forms of photogravure were developed in the 1830s by the original pioneers of photography itself, Henry Fox Talbot in England and Nicéphore Niépce in France. They were seeking a means to make prints that would not fade, by creating photographic images on plates that could then be etched. The etched plates could then be printed using a traditional printing press. These early images were among the first photographs, pre-dating daguerreotypes and the later wet-collodion photographic processes. Fox Talbot worked on extending the process in the 1850s and patented it in 1852 ('photographic engraving') and 1858 ('photoglyphic engraving').
Photogravure in its mature form was developed in 1878 by Czech painter Karel Klíč, who built on Talbot's research. This process, the one still in use today, is called the Talbot-Klič process.
Because of its high quality and richness,
Watercolor (American English) or watercolour (Commonwealth and Ireland), also aquarelle from French, is a painting method. A watercolor is the medium or the resulting artwork in which the paints are made of pigments suspended in a water-soluble vehicle. The traditional and most common support for watercolor paintings is paper; other supports include papyrus, bark papers, plastics, vellum or leather, fabric, wood, and canvas. Watercolors are usually transparent, and appear luminous because the pigments are laid down in a relatively pure form with few fillers obscuring the pigment colors. Watercolor can also be made opaque by adding Chinese white. In East Asia, watercolor painting with inks is referred to as brush painting or scroll painting. In Chinese, Korean, and Japanese painting it has been the dominant medium, often in monochrome black or browns. India, Ethiopia and other countries also have long traditions. Fingerpainting with watercolor paints originated in China.
Although watercolor painting is extremely old, dating perhaps to the cave paintings of paleolithic Europe, and has been used for manuscript illumination since at least Egyptian times but especially in the European
Bakelite ( /ˈbeɪkəlaɪt/ BAY-kə-lyt), or polyoxybenzylmethylenglycolanhydride, is an early plastic. It is a thermosetting phenol formaldehyde resin, formed from an elimination reaction of phenol with formaldehyde. It was developed by Belgian-born chemist Leo Baekeland in New York in 1907.
One of the first plastics made from synthetic components, Bakelite was used for its electrical nonconductivity and heat-resistant properties in electrical insulators, radio and telephone casings, and such diverse products as kitchenware, jewelry, pipe stems, and children's toys. In 1993 Bakelite was designated a National Historic Chemical Landmark by the American Chemical Society in recognition of its significance as the world's first synthetic plastic.
The "retro" appeal of old Bakelite products and labor intensive manufacturing has made them collectible in recent years. Bakelite and Bakelit are registered trademarks of Momentive Specialty Chemicals.
Dr. Baekeland had originally set out to find a replacement for shellac, made from the excretion of lac beetles. Chemists had begun to recognize that many natural resins and fibres were polymers, and Baekeland investigated the reactions of phenol and
Beeswax is a natural wax produced in the bee hive of honey bees of the genus Apis. It is mainly esters of fatty acids and various long chain alcohols. Typically, for a honey beekeeper, 10 pounds of honey yields 1 pound of wax.
The wax is formed by worker bees, who secrete it from eight wax-producing mirror glands on the inner sides of the sternites (the ventral shield or plate of each segment of the body) on abdominal segments 4 to 7. The sizes of these wax glands depend on the age of the worker and after daily flights these glands begin to gradually atrophy. The new wax scales are initially glass-clear and colorless (see illustration), becoming opaque after mastication by the worker bee. The wax of honeycomb is nearly white, but becomes progressively more yellow or brown by incorporation of pollen oils and propolis. The wax scales are about 3 millimetres (0.12 in) across and 0.1 millimetres (0.0039 in) thick, and about 1100 are required to make a gram of wax.
Honey bees use the beeswax to build honeycomb cells in which their young are raised and honey and pollen are stored. For the wax-making bees to secrete wax, the ambient temperature in the hive has to be 33 to 36 °C (91 to
Henri Jean Émile Bénard (June 23, 1844 in Goderville - October 15, 1929 in Paris), was a French architect and painter. Trained at the Beaux-Arts, Bénard was the winner of The Phoebe Hearst International Architectural Competition and the Berkeley Campus in 1899 with his project "Roma." The competition and his design led to the current University of California, Berkeley Campus Architecture.
Bénard's design for the campus architecture won the competition for successfully addressing all of the concerns that the competition's jury had. Bénard's scheme won unanimous praise for having successfully addressed all of the jury's concerns. The elevations were judged to be excellent in scale and proportion, with the drawings done beautifully. The only weakness noted was that some of the buildings in the upper part of the plan were too far from those with related departments, making some rearrangement necessary. In the end, the jury declared Bénard the architect to be entrusted with the execution of the work.
Bénard's plan was appropriately code-named "Roma" for the competition. The plan conjured a city of Parisian buildings organized along a sloping esplanade. The axis continued off campus by
For the British alternative rock band, see Felt (band).
Felt is a non-woven cloth that is produced by matting, condensing and pressing woollen fibres. While some types of felt are very soft, some are tough enough to form construction materials. Felt can be of any colour, and made into any shape or size.
Many cultures have legends as to the origins of feltmaking. Sumerian legend claims that the secret of feltmaking was discovered by Urnamman of Lagash. The story of Saint Clement and Saint Christopher relates that while fleeing from persecution, the men packed their sandals with wool to prevent blisters. At the end of their journey, the movement and sweat had turned the wool into felt socks.
Feltmaking is still practised by nomadic peoples (Altaic people) in Central Asia and northern parts of East Asia (Mongols), where rugs, tents and clothing are regularly made. Some of these are traditional items, such as the classic yurt (Gers), while others are designed for the tourist market, such as decorated slippers. In the Western world, felt is widely used as a medium for expression in textile art as well as design, where it has significance as an ecological textile.
Felt is made by a
Artworks:ST. VALENTINE'S DAY MASSACRE/HOMAGE TO ERROL FLYNN
Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They are among the characteristics that distinguish the extant Aves from other living groups. Feathers have also been noticed in those Theropoda which have been termed feathered dinosaurs. Although feathers cover most parts of the body of birds, they arise only from certain well-defined tracts on the skin. They aid in flight, thermal insulation, waterproofing and coloration that helps in communication and protection.
Feathers are among the most complex integumentary appendages found in vertebrates and are formed in tiny follicles in the epidermis, or outer skin layer, that produce keratin proteins. The β-keratins in feathers, beaks and claws — and the claws, scales and shells of reptiles — are composed of protein strands hydrogen-bonded into β-pleated sheets, which are then further twisted and crosslinked by disulfide bridges into structures even tougher than the α-keratins of mammalian hair,
An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor. Most definitions of the term specify that automobiles are designed to run primarily on roads, to have seating for one to eight people, to typically have four wheels, and to be constructed principally for the transport of people rather than goods.
The term motorcar has also been used in the context of electrified rail systems to denote a car which functions as a small locomotive but also provides space for passengers and baggage. These locomotive cars were often used on suburban routes by both interurban and intercity railroad systems.
It was estimated in 2010 that the number of automobiles had risen to over 1 billion vehicles, with 500 million reached in 1986. The numbers are increasing rapidly, especially in China and India.
The word automobile comes, via the French automobile from the Ancient Greek word αὐτός (autós, "self") and the Latin mobilis ("movable"); meaning a vehicle that moves itself. The alternative name car is believed to originate from the Latin word carrus or carrum ("wheeled vehicle"), or the Middle English word carre
A carpet is a textile floor covering consisting of an upper layer of "pile" attached to a backing. The pile is generally either made from wool or a manmade fibre such as polypropylene, nylon or polyester and usually consists of twisted tufts which are often heat-treated to maintain their structure.
The term "carpet" comes from Old Italian carpita, "carpire" meaning to pluck. The term "carpet" is often used interchangeably with the term "rug". Some define a carpet as stretching from wall to wall. Another definition treats rugs as of lower quality or of smaller size, with carpets quite often having finished ends.
Historically the word was also used for table and wall coverings, as carpets were not commonly used on the floor in European interiors until the 18th century, with the opening of trade routes between Persia and Western Europe.
The carpet is produced on a loom quite similar to woven cloth. The pile can be plush or berber. Plush carpet is a cut pile and berber carpet is a loop pile. There are new styles of carpet combining the two styles called cut and loop carpeting. Normally many colored yarns are used and this process is capable of producing intricate patterns from
Artworks:Memorial to Homosexuals persecuted under Nazism
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.
Video technology was first developed for cathode ray tube (CRT) television systems, but several new technologies for video display devices have since been invented. Charles Ginsburg led an Ampex research team developing the first practical video tape recorder (VTR). In 1951 the first video tape recorder captured live images from television cameras by converting the camera's electrical impulses and saving the information onto magnetic video tape.
Video recorders sold for $50,000 in 1956, and videotape cost $300 per one-hour reel. However, prices steadily dropped over the years; in 1971, Sony began selling videocassette recorder (VCR) tapes to the public. After the invention of the DVD in 1997 and Blu-ray Disc in 2006, sales of videotape and tape equipment plummeted.
Later advances in computer technology allowed computers to capture, store, edit and transmit video clips.
Frame rate, the number of still pictures per unit of time of video, ranges from six or eight frames per second (frame/s) for old mechanical
A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. Butterflies comprise the true butterflies (superfamily Papilionoidea), the skippers (superfamily Hesperioidea) and the moth-butterflies (superfamily Hedyloidea). All the many other families within the Lepidoptera are referred to as moths. The earliest known butterfly fossils date to the mid Eocene epoch, between 40–50 million years ago.
Butterflies exhibit polymorphism, mimicry and aposematism. Some, like the Monarch, will migrate over long distances. Some butterflies have evolved symbiotic and parasitic relationships with social insects such as ants. Some species are pests because in their larval stages they can damage domestic crops or trees; however, some species are agents of pollination of some plants, and caterpillars of a few butterflies (e.g., Harvesters) eat harmful insects. Culturally, butterflies are a popular motif in the visual and
Sandstone (sometimes known as arenite) is a clastic sedimentary rock composed mainly of sand-sized minerals or rock grains.
Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow, red, gray, pink, white and black. Since sandstone beds often form highly visible cliffs and other topographic features, certain colours of sandstone have been strongly identified with certain regions.
Rock formations that are primarily composed of sandstone usually allow percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Fine-grained aquifers, such as sandstones, are more apt to filter out pollutants from the surface than are rocks with cracks and crevices, such as limestone or other rocks fractured by seismic activity.
Sandstone is mined by quarrying. It is sometimes found where there used to be small seas. It is usually formed in deserts or dry places like the Sahara Desert in Africa, the Arabian desert in the Middle East and the Australian desert (including
Artworks:Grigi che si alleggeriscono verso oltremare (Grays Lightening toward...
Rock or a piece of rock shaped or finished for a particular purpose, such as a piece of rock that is used in construction: a coping stone; a paving stone. Stone (the generic rock material in all it's shapes, colors, and forms) is considered a natural resource and has additional uses beyond construction such as a visual art medium, a weapon or projectile, and even as a pet.
Travertine is a form of limestone deposited by mineral springs, especially hot springs. Travertine often has a fibrous or concentric appearance and exists in white, tan, and cream-colored varieties. It is formed by a process of rapid precipitation of calcium carbonate, often at the mouth of a hot spring or in a limestone cave. In the latter, it can form stalactites, stalagmites, and other speleothems. It is frequently used in Italy and elsewhere as a building material.
Travertine is a terrestrial sedimentary rock, formed by the precipitation of carbonate minerals from solution in ground and surface waters, and/or geothermally heated hot-springs. Similar (but softer and extremely porous) deposits formed from ambient-temperature water are known as tufa.
Travertine forms from geothermal springs and is often linked to siliceous systems that form siliceous sinter. Macrophytes, bryophytes, algae, cyanobacteria, and other organisms often colonise the surface of travertine and are preserved, giving travertine its distinctive porosity.
Some springs have temperatures high enough to exclude macrophytes and bryophytes from the deposits. As a consequence, deposits are, in general, less porous
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers (which are strong in tension) embedded in a matrix of lignin which resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in tree roots or in other plants such as shrubs. In a living tree it performs a support function, enabling woody plants to grow large or to stand up for themselves. It also mediates the transfer of water and nutrients to the leaves and other growing tissues. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or wood chips or fiber.
The earth contains about one trillion tonnes of wood, which grows at a rate of 10 billion tonnes per year. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as a source of renewable energy. In 1991, approximately 3.5 billion cubic meters of wood were harvested. Dominant uses were for furniture
A newspaper is a scheduled publication containing news of current events, informative articles, diverse features, editorials, and advertising. It usually is printed on relatively inexpensive, low-grade paper such as newsprint. By 2007, there were 6,580 daily newspapers in the world selling 395 million copies a day. The worldwide recession of 2008, combined with the rapid growth of web-based alternatives, caused a serious decline in advertising and circulation, as many papers closed or sharply retrenched operations.
General-interest newspapers typically publish stories on local and national political events and personalities, crime, business, entertainment, society and sports. Most traditional papers also feature an editorial page containing editorials written by an editor and columns that express the personal opinions of writers. The newspaper is typically funded by paid subscriptions and advertising.
A wide variety of material has been published in newspapers, including editorial opinions, criticism, persuasion and op-eds; obituaries; entertainment features such as crosswords, sudoku and horoscopes; weather news and forecasts; advice, food and other columns; reviews of radio,
Leather is a durable and flexible material created by the tanning of animal rawhide and skin, often cattle hide. It can be produced through manufacturing processes ranging from cottage industry to heavy industry.
Several tanning processes transform hides and skins into leather:
Leather—usually vegetable-tanned—can be oiled to improve its water resistance. This supplements the natural oils remaining in the leather itself, which can be washed out through repeated exposure to water. Frequent oiling of leather, with mink oil, neatsfoot oil, or a similar material keeps it supple and improves its lifespan dramatically.
Leather with the hair still attached is called hair-on.
In general, leather is sold in four forms:
Less-common leathers include:
There are two other types of leather commonly used in specialty products, such as briefcases, wallets, and luggage:
The following are not "true" leathers, but contain leather material. Depending on jurisdiction, they may still be labeled as "Genuine Leather":
Today most leather is made of cattle skin but many exceptions exist. Lamb and deerskin are used for soft leather in more expensive apparel. Deer and elkskin are widely used in work gloves
Mortar is a workable paste used to bind construction blocks together and fill the gaps between them. The blocks may be stone, brick, cinder blocks, etc. Mortar becomes hard when it sets, resulting in a rigid aggregate structure. Modern mortars are typically made from a mixture of sand, a binder such as cement or lime, and water. Mortar can also be used to fix, or point, masonry when the original mortar has washed away.
The first mortars were made of mud and clay. Because of a lack of stone and an abundance of clay, Babylonian constructions were of baked brick, using lime or pitch for mortar. According to Roman Ghirshman, the first evidence of humans using a form of mortar was at the ziggurat of Sialk in Iran, built of sun-dried bricks in 2900 BC. The Chogha Zanbil Temple in Iran was built in about 1250 BC with kiln-fired bricks and a strong mortar of bitumen.
In early Egyptian pyramids constructed about 2600–2500 BC, the limestone blocks were bound by mortar of mud and clay, or clay and sand. In later Egyptian pyramids, the mortar was made of either gypsum or lime. Gypsum mortar was essentially a mixture of plaster and sand and was quite soft.
In the Indian subcontinent, multiple
Muslin (/ˈmʌslɨn/ or /ˈmjuːslɨn/) is a loosely-woven cotton fabric which originated in Bangladesh, which was introduced to Europe from the Middle East in the 17th century. It became very popular at the end of the 18th century in France. Muslin is most typically an unbleached or white cloth, produced from carded cotton yarn. It is often used to make sewing patterns, such as for clothing, curtains, or upholstery. Because air moves easily through muslin, muslin clothing is suitable for hot, dry climates.
Muslin clothes were traded by ancient Greeks from the Indian port town Machilipatnam, which was called Maisolos or Masalia in ancient times. Some believe that the name muslin originated from the name Maisolos. Marco Polo, the famous traveller, visited the Kakatiya kingdom in which Machilipatnam was located and praised the muslins available there. In 1298, Marco Polo described the cloth in his book The Travels. He said that it was made in Mosul, Iraq. Although this view has the fabric named after the city where Europeans first encountered it (Mosul), the fabric is believed to have originated in Dhaka, which is now the capital of Bangladesh. In the 9th century, an Arab merchant named
A postcard or post card is a rectangular piece of thick paper or thin cardboard intended for writing and mailing without an envelope.
In some places, it is possible to send them for a lower fee than for a letter. Stamp collectors distinguish between postcards (which require a stamp) and postal cards (which have the postage pre-printed on them). While a postcard is usually printed by a private company, individual or organization, a postal card is issued by the relevant postal authority. The United States Postal Service defines a postcard as: rectangular, at least 3+⁄2 inches (88.9 mm) high × 5 inches (127 mm) long × 0.007 inches (0.178 mm) thick and no more than 4+⁄4 inches (108 mm) high × 6 inches (152.4 mm) long × 0.016 inches (0.406 mm) thick. However, some postcards have deviated from this (for example, shaped postcards).
The study and collecting of postcards is termed deltiology.
Cards with messages had been sporadically created and posted by individuals since the creation of postal services. The earliest known picture postcard was a hand-painted design on card, posted in London to the writer Theodore Hook in 1840 bearing a penny black stamp. He probably created and posted the
Silk is a natural protein fibre, some forms of which can be woven into textiles. The protein fibre of silk is composed mainly of fibroin and produced by certain insect larvae to form cocoons. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity (sericulture). The shimmering appearance of silk is due to the triangular prism-like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles, thus producing different colors.
Silks are produced by several other insects, but generally only the silk of moth caterpillars has been used for textile manufacturing. There has been some research into other silks, which differ at the molecular level. Many silks are mainly produced by the larvae of insects undergoing complete metamorphosis, but some adult insects such as webspinners produce silk, and some insects such as raspy crickets produce silk throughout their lives. Silk production also occurs in Hymenoptera (bees, wasps, and ants), silverfish, mayflies, thrips, leafhoppers, beetles, lacewings, fleas, flies and midges. Other types of arthropod produce silk, most notably various
Sterling silver is an alloy of silver containing 92.5% by mass of silver and 7.5% by mass of other metals, usually copper. The sterling silver standard has a minimum millesimal fineness of 925.
Fine silver is 99.9% pure and is generally too soft for producing functional objects; therefore, the silver is usually alloyed with copper to give it strength while preserving the ductility and beauty of the precious metal. Other metals can replace the copper, usually with the intent to improve various properties of the basic sterling alloy such as reducing casting porosity, eliminating firescale, and increasing resistance to tarnish. These replacement metals include germanium, zinc and platinum, as well as a variety of other additives, including silicon and boron. A number of alloys, such as Argentium sterling silver, have appeared in recent years, formulated to lessen firescale or to inhibit tarnish, and this has sparked heavy competition among the various manufacturers, who are rushing to make claims of having the best formulation. However, no one alloy has emerged to replace copper as the industry standard, and alloy development is a very active area.
One of the earliest attestations of
Tintype, also melainotype and ferrotype, is a photograph made by creating a direct positive on a sheet of iron metal that is blackened by painting, lacquering or enamelling and is used as a support for a collodion photographic emulsion.
Photographers usually worked outside at fairs, carnivals etc. and as the support of the tintype (there is no actual tin used) is resilient and does not need drying, photographs can be produced only a few minutes after the picture is taken.
An ambrotype uses the same process and methods on a sheet of glass that is mounted in a case with a black backing so the underexposed negative image appears as a positive. Tintypes did not need mounting in a case and were not as delicate as photographs that used glass for the support.
The process is very similar to wet plate photography, where silver halide crystals are suspended in a collodion emulsion that is chemically reduced to crystals of metallic silver that vary in density in accordance with variations in the intensity and duration of light impinging on the emulsion.
In a tintype, a very underexposed negative image is produced on a thin iron plate, lacquered or otherwise darkened, and coated with a
Weathering steel, best-known under the trademark COR-TEN steel and sometimes written without the hyphen as "Corten steel", is a group of steel alloys which were developed to eliminate the need for painting, and form a stable rust-like appearance if exposed to the weather for several years.
United States Steel Corporation (USS) holds the registered trademark on the name COR-TEN. Although USS sold its discrete plate business to International Steel Group (now Arcelor-Mittal) in 2003, it still sells COR-TEN branded material in strip-mill plate and sheet forms.
The original COR-TEN received the standard designation A 242 ("COR-TEN A") from the ASTM International standards group. Newer ASTM grades are A 588 ("COR-TEN B") and A 606 for thin sheet. All alloys are in common production and use.
"Weathering" means that due to their chemical compositions, these steels exhibit increased resistance to atmospheric corrosion compared to other steels. This is because the steel forms a protective layer on its surface under the influence of the weather.
The corrosion-retarding effect of the protective layer is produced by the particular distribution and concentration of alloying elements in it. The
Woodblock printing in Japan (Japanese: 木版画, moku hanga) is a technique best known for its use in the ukiyo-e artistic genre; however, it was also used very widely for printing books in the same period. Woodblock printing had been used in China for centuries to print books, long before the advent of movable type, but was only widely adopted in Japan surprisingly late, during the Edo period (1603-1867). Although similar to woodcut in western printmaking in some regards, the moku hanga technique differs in that it uses water-based inks—as opposed to western woodcut, which often uses oil-based inks. The Japanese water-based inks provide a wide range of vivid colors, glazes, and transparency.
Woodblock-printed books from Chinese Buddhist temples were seen in Japan as early as the eighth century. In 764 the Empress Kōken commissioned one million small wooden pagodas, each containing a small woodblock scroll printed with a Buddhist text (Hyakumanto Darani). These were distributed to temples around the country as thanksgiving for the suppression of the Emi Rebellion of 764. These are the earliest examples of woodblock printing known, or documented, from Japan.
By the eleventh century,
Aquatint is an intaglio printmaking technique, a variant of etching.
In intaglio printmaking, you make marks on the matrix (in the case of aquatint, a copper or zinc plate) that are capable of holding ink. The inked plate is passed through a printing press together with a sheet of paper, resulting in a transfer of the ink to the paper. This can be repeated a number of times, depending on the particular technique.
Like etching, aquatint uses the application of acid to make the marks in the metal plate. Where the engraving technique uses a needle to make lines that print in black (or whatever colour ink is used), aquatint uses powdered rosin to create a tonal effect. The rosin is acid resistant and typically adhered to the plate by controlled heating. The tonal variation is controlled by the level of acid exposure over large areas, and thus the image is shaped by large sections at a time. Another tonal technique, mezzotint, begins with a plate surface that is evenly indented so that it will carry a fairly dark tone of ink. The mezzotint plate is then smoothed and polished to make areas carry less ink and thus print a lighter shade; or, beginning with a smooth plate, areas are
Drypoint is a printmaking technique of the intaglio family, in which an image is incised into a plate (or "matrix") with a hard-pointed "needle" of sharp metal or diamond point. Traditionally the plate was copper, but now acetate, zinc, or plexiglas are also commonly used. Like etching, drypoint is easier for an artist trained in drawing to master than engraving, as the technique of using the needle is closer to using a pencil than the engraver's burin.
The lines produced by printing a drypoint are formed by the burr thrown up at the edge of the incised lines, in addition to the depressions formed in the surface of the plate. A larger burr, formed by a steep angle of the tool, will hold a lot of ink, producing a characteristically soft, dense line that differentiates drypoint from other intaglio methods such as etching or engraving which produce a smooth, hard-edged line. The size or characteristics of the burr usually depend not on how much pressure is applied, but on the angle of the needle. A perpendicular angle will leave little to no burr, while the smaller the angle gets to either side, the larger the burr pileup. The deepest drypoint lines leave enough burr on either side of
Enamel paint is paint that air dries to a hard, usually glossy, finish, used for coating surfaces that are outdoors or otherwise subject to hard wear or variations in temperature; it should not be confused with decorated objects in "painted enamel", where vitreous enamel is applied with brushes and fired in a kiln. The name is something of a misnomer as in reality, most commercially available enamel paints are significantly softer than either vitreous enamel or stoved synthetic resins, and are totally different in composition; vitreous enamel is applied as a powder or paste and then fired at high temperature. There is no generally accepted definition or standard for use of the term enamel paint, and not all enamel-type paints may use it.
Typically the term "enamel paint" is used to describe oil-based covering products, usually with a significant amount of gloss in them, however recently many latex or water-based paints have adopted the term as well. The term today means "hard surfaced paint" and usually is in reference to paint brands of higher quality, floor coatings of a high gloss finish, or spray paints. Some enamel paints have been made by adding varnish to oil-based
Linen ( /ˈlɪnɨn/) is a textile made from the fibers of the flax plant, Linum usitatissimum. Linen is labor-intensive to manufacture, but when it is made into garments, it is valued for its exceptional coolness and freshness in hot weather.
The word "linen" is cognate with the Latin for the flax plant, which is linum, and the earlier Greek linon. This word history has given rise to a number of other terms in English, the most notable of which is the English word line, derived from the use of a linen (flax) thread to determine a straight line.
Textiles in a linen weave texture, even when made of cotton, hemp and other non-flax fibers are also loosely referred to as "linen". Such fabrics generally have their own specific names other than linen; for example, fine cotton yarn in a linen-style weave is called Madapolam.
The collective term "linens" is still often used generically to describe a class of woven and even knitted bed, bath, table and kitchen textiles. The name linens is retained because traditionally, linen was used for many of these items. In the past, the word "linens" was also used to mean lightweight undergarments such as shirts, chemises, waistshirts, lingerie (a word
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets.
Paper is a versatile material with many uses. Whilst the most common is for writing and printing upon, it is also widely used as a packaging material, in many cleaning products, in a number of industrial and construction processes, and even as a food ingredient – particularly in Asian cultures.
Paper, and the pulp papermaking process, was said to be developed in China during the early 2nd century AD by the Han court eunuch Cai Lun, although the earliest archaeological fragments of paper derive from the 2nd century BC in China.
The oldest known archaeological fragments of the immediate precursor to modern paper date to 2nd century BC in China. Papermaking is considered one of the Four Great Inventions of China, and the pulp papermaking process is ascribed to Cai Lun, a 2nd century AD Han court eunuch. With paper an effective substitute for silk in many applications, China could export silk in greater quantity, contributing to a Golden
Letterpress is relief printing. It involves locking movable type into the bed of a press, inking it, and rolling or pressing paper against it to form an impression. It was the normal form of printing text from its invention by Johannes Gutenberg in the mid-15th century until the 19th century and remained in wide use for books and other uses until the second half of the 20th century. In addition to the direct impression of inked movable type onto paper or another receptive surface, letterpress is also the direct impression of inked printmaking blocks such as photo-etched zinc "cuts" (plates), linoleum blocks, wood engravings, etc., using such a press.
Letterpress printing remained the primary way to print and distribute information until the twentieth century, when offset printing was developed. It was also an extremely important technological innovation, making printed material available to a wider range of classes of people.
In about 1440, Johannes Gutenberg is credited with the invention of modern movable type printing from individually cast, reusable letters set together in a form (frame or chase). He also invented a wooden printing press, based on the extant wine press, where
Wool is the textile fiber obtained from sheep and certain other animals, including cashmere from goats, mohair from goats, qiviut from muskoxen, vicuña, alpaca, camel from animals in the camel family, and angora from rabbits.
Wool has several qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters). In the U.S. the term wool is usually restricted to describing the fibrous protein derived from the specialized skin cells called follicles in sheep, although in the U.K. it may be used of any long curling fiber such as wood wool, wire wool, etc.
Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat. Insulation also works both ways; Bedouins and Tuaregs use wool clothes to keep heat out and protect the body.
The amount of crimp corresponds to the fineness of the wool fibers. A fine wool like Merino may have up to 100 crimps per inch, while the coarser wools like karakul may have as few as 1 to 2. Hair, by contrast, has
Collotype is a dichromate-based photographic process invented by Alphonse Poitevin in 1856. and was used for large volume mechanical printing before the existence of cheaper offset lithography. It can produce results difficult to distinguish from metal-based photographic prints because of its microscopically fine reticulations which comprise the image. Many old postcards are collotypes. While no longer a commercial process, its possibilities for fine art photography were first employed in the United States by Alfred Stieglitz.
The collotype plate is made by coating a plate of glass or metal with a substrate composed of gelatin or other colloid and hardening it. Then it is coated with a thick coat of dichromated gelatine and dried carefully at a controlled temperature (a little over 50 degrees Celsius) so it 'reticulates' or breaks up into a finely grained pattern when washed later in approximately 16 °C water. The plate is then exposed in contact with the negative using an ultraviolet (UV) light source which changes the ability of the exposed gelatine to absorb water later. The plate is developed by carefully washing out the dichromate salt and dried without heat. The plate is left
Intaglio ( /ɪnˈtæli.oʊ/ in-TAL-ee-oh) is the family of printing and printmaking techniques in which the image is incised into a surface, and the incised line or sunken area holds the ink. It is the direct opposite of a relief print.
Normally, copper or zinc plates are used as a surface or matrix, and the incisions are created by etching, engraving, drypoint, aquatint or mezzotint. Collographs may also be printed as intaglio plates.
In the form of intaglio printing called etching, the plate is covered in a resin ground or an acid-resistant wax material. Using an etching needle, or a similar tool, the image is engraved into the ground, revealing the plate underneath. The plate is then dipped into acid. The acid bites into the surface of the plate where it was exposed. Biting is a printmaking term to describe the acid's etching, or incising, of the image. After the plate is sufficiently bitten, the plate is removed from the acid bath, and the ground is removed to prepare for the next step in printing.
To print an intaglio plate, ink is applied to the surface by wiping and/or dabbing the plate to push the ink into the bitten grooves. The plate is and then rubbed with tarlatan cloth to
Formica is a brand of composite materials manufactured by the Formica Corporation now based in Newcastle, Tyne & Wear, a division of the New Zealand company Fletcher Building. In common use, the term refers to the company's classic product, a heat-resistant, wipe-clean, plastic laminate of paper or fabric with melamine resin.
Formica was invented in 1912 by Daniel J. O'Conor and Herbert A. Faber, then working at Westinghouse which filed for a patent on it. They originally conceived it as a substitute for mica used as electrical insulation, made of wrapped woven fabric coated with Bakelite thermosetting resin, then slit lengthwise, flattened, and cured in a press. They left Westinghouse immediately afterwards.
The name Formica now refers primarily to the decorative product composed of several layers of kraft paper impregnated with melamine thermosetting resin and topped with a decorative layer protected by melamine, then compressed and cured with heat to make a hard, durable surface.
The mineral mica was commonly used at that time for electrical insulation. Because the new product acted as a substitute “for mica”, Faber coined the name “Formica” This was in fact a preexisting word,
Pastel is an art medium in the form of a stick, consisting of pure powdered pigment and a binder. The pigments used in pastels are the same as those used to produce all colored art media, including oil paints; the binder is of a neutral hue and low saturation.
The color effect of pastels is closer to the natural dry pigments than that of any other process.
The noun "pastel" gives rise to:
Pastel sticks or crayons consist of pure powdered pigment combined with a binder. The exact composition and characteristics of an individual pastel stick depends on the type of pastel and the type and amount of binder used. It also varies by individual manufacturer.
Dry pastels have historically used binders such as gum arabic and gum tragacanth. Methyl cellulose was introduced as a binder in the twentieth century. Often a chalk or gypsum component is present. They are available in varying degrees of hardness, the softer varieties being wrapped in paper. Some pastel brands use pumice in the binder to abrade the paper and create more tooth.
Dry pastel media can be subdivided as follows:
In addition, pastels using a different approach to manufacture have been developed:
There has been some debate
Straw is an agricultural by-product, the dry stalks of cereal plants, after the grain and chaff have been removed. Straw makes up about half of the yield of cereal crops such as barley, oats, rice, rye and wheat. It has many uses, including fuel, livestock bedding and fodder, thatching and basket-making. It is usually gathered and stored in a straw bale, which is a bundle of straw tightly bound with twine or wire. Bales may be square, rectangular, or round, depending on the type of baler used.
Current and historic uses of straw include:
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous (e.g., a glass). Because most common ceramics are crystalline, the definition of ceramic is often restricted to inorganic crystalline materials, as opposed to the noncrystalline glasses.
The earliest ceramics were pottery objects or 27,000 year old figurines made from clay, either by itself or mixed with other materials, hardened in fire. Later ceramics were glazed and fired to create a colored, smooth surface. Ceramics now include domestic, industrial and building products and art objects. In the 20th century, new ceramic materials were developed for use in advanced ceramic engineering; for example, in semiconductors.
The word "ceramic" comes from the Greek word κεραμικός (keramikos), "of pottery" or "for pottery", from κέραμος (keramos), "potter's clay, tile, pottery". The earliest mention of the root "ceram-" is the Mycenaean Greek ke-ra-me-we, "workers of ceramics", written in Linear b syllabic script. "Ceramic" may be used as an adjective describing a material, product or process; or as
OS X ( /oʊ ˌɛs ˈtɛn/), formerly Mac OS X, is a series of Unix-based graphical interface operating systems developed, marketed, and sold by Apple Inc. OS X is designed to run exclusively on Macintosh computers, having been pre-loaded on all Macs since 2002. OS X, whose X is the Roman numeral for 10 and is a prominent part of its brand identity, is built on technologies developed at NeXT between the second half of the 1980s and Apple's purchase of the company in late 1996. It was the successor to Mac OS 9, released in 1999, the final release of the "classic" Mac OS, which had been Apple's primary operating system since 1984. Apple also uses 'X' in 'OS X' to emphasize the relatedness between OS X and UNIX. Mac OS X v10.5 "Leopard" running on Intel processors, Mac OS X v10.6 "Snow Leopard", OS X v10.7 "Lion" and OS X v10.8 "Mountain Lion" have obtained UNIX 03 certification. iOS, which runs on the iPhone, iPod Touch, iPad, and the 2nd and 3rd generation Apple TV, shares the Darwin core and many frameworks with OS X. An unnamed variant of Mac OS X 10.4 powered the first generation Apple TV.
OS X originally ran on PowerPC-based Macs. In 2006, the first Intel Macs had a specialized
A tile is a manufactured piece of hard-wearing material such as ceramic, stone, metal, or even glass. Tiles are generally used for covering roofs, floors, walls, showers, or other objects such as tabletops. Alternatively, tile can sometimes refer to similar units made from lightweight materials such as perlite, wood, and mineral wool, typically used for wall and ceiling applications. In another sense, a tile is a construction tile or similar object, such as rectangular counters used in playing games (see tile-based game). The word is derived from the French word tuile, which is, in turn, from the Latin word tegula, meaning a roof tile composed of fired clay. Tiles are often used to form wall and floor coverings, and can range from simple square tiles to complex mosaics. Tiles are most often made from porcelain, fired clay or ceramic with a hard glaze, but other materials are also commonly used, such as glass, metal, cork, and stone. Tiling stone is typically marble, onyx, granite or slate. Thinner tiles can be used on walls than on floors, which require thicker, more durable surfaces.
Ceramic with a water absorption rate of more than 10% after firing it at temperatures between 950
Suede /ˈsweɪd/ is a type of leather with a napped finish, commonly used for jackets, shoes, shirts, purses, furniture and other items. The term comes from the French "gants de Suède", which literally means "Swedish gloves".
Suede leather is made from the underside of the skin, primarily lamb, although goat, pig, calf and deer are commonly used. Splits from thick hides of cow and deer are also sueded, but, due to the fibre content, have a shaggy nap. Because suede does not include the tough exterior skin layer, suede is less durable but softer than standard ("full-grain") leather. Its softness, thinness, and pliability make it suitable for clothing and delicate uses; suede was originally used for women's gloves. Suede leather is also popular in upholstery, shoes, bags, and other accessories, and as a lining for other leather products. Due to its textured nature and open pores, suede may become dirty and absorb liquids quickly.
Fabrics are often manufactured with a brushed or napped finish to resemble suede leather. These products often provide a similar look and feel to suede, but have advantages such as increased liquid or stain resistance, and may appeal to consumers who prefer a
Beadwork is the art or craft of attaching beads to one another or to cloth, usually by the use of a needle and thread or soft, flexible wire. Most beadwork takes the form of jewelry or other personal adornment, but beads are also used in wall hangings and sculpture.
Beadwork techniques are broadly divided into loom and off-loom weaving, stringing, bead embroidery, bead crochet, and bead knitting.
Most cultures have employed beads for personal adornment. Archaeological records show that people made and used beads as long as 5,000 years ago. Beads have also been used for religious purposes, as good luck talismans, and as curative agents.
Modern beadwork is often used as a creative hobby to create jewelry, purses, coasters, and dozens of other crafts. Beads are available in many different designs, sizes, colors, and materials, allowing much variation among bead artisans and projects. Simple projects can be created in less than an hour by novice beaders, while complex beadwork may take weeks of meticulous work with specialized tools and equipment.
3D beading is less common than 2D beading, largely because free 3D beading patterns are not well distributed on the internet. Resources are
Beaverboard (also beaver board) is a light wood-like building material, formed of wood fibre compressed into sheets. It was originally a trademark. It has occasionally been used as a canvas by artists; most famously, the iconic painting American Gothic (1930) by Grant Wood is painted on a beaverboard panel.
Eggs are laid by females of many different species, including birds, reptiles, amphibians, and fish, and have probably been eaten by mankind for millennia. Bird and reptile eggs consist of a protective eggshell, albumen (egg white), and vitellus (egg yolk), contained within various thin membranes. Popular choices for egg consumption are chicken, duck, quail, roe, and caviar, but the egg most often consumed by humans is the chicken egg, by a wide margin.
Egg yolks and whole eggs store significant amounts of protein and choline, and are widely used in cookery. Due to their protein content, the United States Department of Agriculture (USDA) categorizes eggs as Meats within the Food Guide Pyramid. Despite the nutritional value of eggs, there are some potential health issues arising from egg quality, storage, and individual allergies.
Chickens and other egg-laying creatures are widely kept throughout the world, and mass production of chicken eggs is a global industry. In 2009, an estimated 62.1 million metric tons of eggs were produced worldwide from a total laying flock of approximately 6.4 billion hens. There are issues of regional variation in demand and expectation, as well as
Etching is the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio in the metal (the original process—in modern manufacturing other chemicals may be used on other types of material). As an intaglio method of printmaking, it is, along with engraving, the most important technique for old master prints, and remains in wide use today.
In pure etching, a metal (usually copper, zinc or steel) plate is covered with a waxy ground which is resistant to acid. The artist then scratches off the ground with a pointed etching needle where he or she wants a line to appear in the finished piece, so exposing the bare metal. The échoppe, a tool with a slanted oval section, is also used for "swelling" lines. The plate is then dipped in a bath of acid, technically called the mordant (French for "biting") or etchant, or has acid washed over it. The acid "bites" into the metal, where it is exposed, leaving behind lines sunk into the plate. The remaining ground is then cleaned off the plate. The plate is inked all over, and then the ink wiped off the surface, leaving only the ink in the etched lines.
The plate is then put through a
Plywood is a manufactured wood panel made from thin sheets of wood veneer. It is one of the most widely used wood products. It is flexible, inexpensive, workable, re-usable, and can usually be locally manufactured. Plywood is used instead of plain wood because of its resistance to cracking, shrinkage, splitting, and twisting/warping, and its general high degree of strength.
Plywood layers (called veneers) are glued together with adjacent plies having their wood grain at right angles to each other. Cross-graining has several important benefits: it reduces the tendency of wood to split when nailed at the edges, it reduces expansion and shrinkage equating to improved dimensional stability, and it makes the strength of the panel consistent across both directions. There are usually an odd number of plies so that the sheet is balanced—this reduces warping. Because of the way plywood is bonded (with grains running against one another and with an odd number of composite parts) it is very hard to bend it perpendicular to the grain direction.
Plywood was invented around 3400 B.C. by the Ancient Mesopotamians, who attached several thinner layers of wood together to make one thick layer. They
Steel is an alloy made by combining iron and other elements, the most common of these being carbon. When carbon is used, its content in the steel is between 0.2% and 2.1% by weight, depending on the grade. Other alloying elements sometimes used are manganese, chromium, vanadium and tungsten.
Carbon and other elements act as a hardening agent, preventing dislocations in the iron atom crystal lattice from sliding past one another. Varying the amount of alloying elements and the form of their presence in the steel (solute elements, precipitated phase) controls qualities such as the hardness, ductility, and tensile strength of the resulting steel. Steel with increased carbon content can be made harder and stronger than iron, but such steel is also less ductile than iron.
Alloys with a higher than 2.1% carbon content are known as cast iron because of their lower melting point and good castability. Steel is also distinguishable from wrought iron, which can contain a small amount of carbon, but it is included in the form of slag inclusions. Two distinguishing factors are steel's increased rust resistance and better weldability.
Though steel had been produced by various inefficient methods
Tin-glazed pottery is pottery covered in glaze containing tin oxide which is white, shiny and opaque. (See tin-glazing.) The pottery body is usually made of red or buff colored earthenware and the white glaze was often used to imitate Chinese porcelain. Tin-glazed pottery is usually decorated, the decoration applied to the unfired glaze surface by brush as metallic oxides, commonly cobalt oxide, copper oxide, iron oxide, manganese dioxide and antimony oxide. The makers of Italian tin-glazed pottery from the late Renaissance blended oxides to produce detailed and realistic polychrome paintings.
The earliest tin-glazed pottery appears to have been made in Iraq in the 9th century, the oldest fragments having been excavated during the First World War from the palace of Samarra about fifty miles north of Baghdad. From there it spread to Egypt, Persia and Spain before reaching Italy in the Renaissance, Holland in the 16th century and England, France and other European countries shortly after.
The development of white, or near white, firing bodies in Europe from the late 18th century, such as Creamware by Josiah Wedgwood and porcelain, reduced the demand for Delftware, faience and
Artworks:The Bride Stripped Bare By Her Bachelors, Even
A wire is a single, usually cylindrical, flexible strand or rod of metal. Wires are used to bear mechanical loads and to carry electricity and telecommunications signals. Wire is commonly formed by drawing the metal through a hole in a die or draw plate. Standard sizes are determined by various wire gauges. The term wire is also used more loosely to refer to a bundle of such strands, as in 'multistranded wire', which is more correctly termed a wire rope in mechanics, or a cable in electricity.
Although usually circular in cross-section, wire can be made in square or flattened rectangular cross-section, either for decorative purposes, or for technical purposes such as high-efficiency voice coils in loudspeakers. Edge-wound coil springs, such as the "Slinky" toy, are made of special flattened wire.
In antiquity, jewelry often contains, in the form of chains and applied decoration, large amounts of wire that is accurately made and which must have been produced by some efficient, if not technically advanced, means. In some cases, strips cut from metal sheet were made into wire by pulling them through perforations in stone beads. This causes the strips to fold round on themselves to
Artworks:Edge of a City: Spiroid Sectors, Dallas/Fort Worth, Texas, 1990--91 (Model)
Concrete is a composite construction material composed primarily of aggregate, cement, and water. There are many formulations, which provide varied properties. The aggregate is generally a coarse gravel or crushed rocks such as limestone, or granite, along with a fine aggregate such as sand. The cement, commonly Portland cement, and other cementitious materials such as fly ash and slag cement, serve as a binder for the aggregate. Various chemical admixtures are also added to achieve varied properties. Water is then mixed with this dry composite, which enables it to be shaped (typically poured) and then solidified and hardened into rock-hard strength through a chemical process called hydration. The water reacts with the cement, which bonds the other components together, eventually creating a robust stone-like material. Concrete has relatively high compressive strength, but much lower tensile strength. For this reason it is usually reinforced with materials that are strong in tension (often steel). Concrete can be damaged by many processes, such as the freezing of trapped water.
Concrete is widely used for making architectural structures, foundations, brick/block walls, pavements,
Acrylic paint is fast drying paint containing pigment suspension in acrylic polymer emulsion. Acrylic paints can be diluted with water, but become water-resistant when dry. Depending on how much the paint is diluted (with water) or modified with acrylic gels, media, or pastes, the finished acrylic painting can resemble a watercolor or an oil painting, or have its own unique characteristics not attainable with other media.
Leonard Bocour and Sam Golden between 1946 and 1949 had invented a solution acrylic paint under the brand Magna paint. A waterborne acrylic paint called "Aquatec" would soon follow. Otto Rohm invented acrylic resin, which quickly transformed into acrylic paint. Acrylics were first made commercially available in the 1950s. These were mineral spirit-based paints called Magna. In 1953, the year that Rohm and Haas developed the first acrylic emulsions, Jose L. Gutierrez produced Politec Acrylic Artists Colors in Mexico and Permanent Pigments Co of Cincinnati Ohio produced Liquitex colors. These two product lines were the very first acrylic emulsion artists paints. Water-based acrylic paints were subsequently sold as "latex" house paints, although acrylic dispersion
A bead is a small, decorative object that is usually pierced for threading or stringing. Beads range in size from under 1 millimetre (0.039 in) to over 1 centimetre (0.39 in) in diameter. A pair of beads made from Nassarius sea snail shells, approximately 100,000 years old, are thought to be the earliest known examples of jewellery. Beadwork is the art or craft of making things with beads. Beads can be woven together with specialized thread, strung onto thread or soft, flexible wire, or adhered to a surface (e.g. fabric, clay).
Beads may be divided into several types of overlapping categories, based on different criteria such as component materials, manufacturing process, place or period of origin, surface patterning, or general shape. In some cases, such as millefiori and cloisonné beads, multiple categories may overlap in an inseparably interdependent fashion.
Beads can be made of many types of materials. The earliest beads were made of convenient natural materials; when found, these could be readily drilled and shaped. As human technology became capable of obtaining or working with more difficult natural materials, those were added to the range of available substances. The same
Conté, also known as Conté sticks or Conté crayons, are a drawing medium composed of compressed powdered graphite or charcoal mixed with a wax or clay base, square in cross-section. They were invented in 1795 by Nicolas-Jacques Conté, who created the combination of clay and graphite in response to the shortage of graphite caused by the Napoleonic Wars (the British naval blockade of France prevented import). Conté crayons had the advantage of being cost-effective to produce, and easy to manufacture in controlled grades of hardness.
They are now manufactured using natural pigments (iron oxides, carbon black, titanium dioxide), clay (kaolin), and a binder (cellulose ether).
Conté crayons are most commonly found in black, white, and sanguine tones, as well as bistre, shades of grey, and other colors. Currently in the USA, sets of 12 assorted, portrait and landscape colors are available as well as a sketching set, plus sets of 18, 24 or 48 colors. In Europe, 22 more colors are available and the colors other than sanguine, bistre, grey, black and white are available open stock.
Colors sets are especially useful for field studies and color studies. Some artists create entire paintings
Nacre ( /ˈneɪkər/ NAY-kər), also known as mother of pearl, is an organic-inorganic composite material produced by some mollusks as an inner shell layer; it is also what makes up the outer coating of pearls. It is very strong, resilient, and iridescent.
Nacre is found in some of the more ancient lineages of bivalves, gastropods and cephalopods. However, the inner layer in the great majority of mollusk shells is porcellaneous, not nacreous, and this usually results in a non-iridescent shine, or more rarely in non-nacreous iridescence such as flame structure as is found in conch pearls.
The outer layer of pearls and the inside layer of pearl oyster and freshwater pearl mussel shells are made of nacre. Many other families of mollusk also have a nacreous inner shell layer, including marine gastropods such as the Haliotidae, the Trochidae and the Turbinidae.
Nacre appears iridescent because the thickness of the aragonite platelets is close to the wavelength of visible light. This results in constructive and destructive interference of different wavelengths of light, resulting in different colors of light being reflected at different viewing angles.
Nacre is composed of hexagonal
Twine is a light string or strong thread composed of two or more smaller strands or yarns twisted together. More generally, the term can be applied to any thin cord.
Natural fibres used for making twine include cotton, sisal, jute, hemp, henequen, and coir. A variety of synthetic fibres may also be used.
Acer ( /ˈeɪsər/) is a genus of trees or shrubs commonly known as maple.
Maples are variously classified in a family of their own, the Aceraceae, or together with the Hippocastanaceae included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group system, favour inclusion in Sapindaceae. The type species of the genus is Acer pseudoplatanus (Sycamore maple).
There are approximately 128 species, most of which are native to Asia, with a number also appearing in Europe, northern Africa, and North America. Only one species, the poorly studied Acer laurinum, is native to the Southern Hemisphere. Fifty-four species of maples meet the International Union for Conservation of Nature criteria for being under threat of extinction in their native habitat.
The word Acer derives from a Latin word meaning "sharp" (compare "acerbic"), referring to the characteristic points on maple leaves. It was first applied to the genus by the French botanist Joseph Pitton de Tournefort in 1700. The earliest known fossil maple is Acer alaskense, from the Latest Paleocene of Alaska.
Most maples are trees growing to 10 – 45 m (30 – 145 ft) in height. Others are shrubs less than
Pavonazzo marble is a white marble from Italy.
The name derives from the Italian word for peacock (pavone). "In natural stone trade, Pavonazzo is often simply called a Marble." It is one of the many varieties of Carrara marble, distinguished by black/gray-veined white marble. Also referred to as "pavonazzetto", and distinguished as "(1.) Various red and purplish marbles and brescias. (2.) A marble, used by the ancient Romans, characterized by very irregular veins of dark red with bluish and yellowish tints."
The marble has been used in Pompeii, the Trajan's Markets, and internationally in the influential Baroque Revival-style historic buildings the Church of St. Ignatius Loyola, in New York City, and Belfast City Hall in Belfast, Northern Ireland.
Stencil graffiti makes use of a paper, cardboard, or other media to create an image or text that is easily reproducible. The desired design is cut out of the selected medium and then the image is transferred to a surface through the use of spray paint or roll-on paint.
The process of stenciling involves applying paint across a stencil to form an image on a surface below. Sometimes multiple layers of stencils are used on the same image to add colours or create the illusion of depth.
Those who make and apply stencils have many motivations. For some, it is an easy method to produce a political message. Many artists appreciate the publicity that their artwork can receive. And some just want their work to be seen. Since the stencil stays uniform throughout its use, it is easier for an artist to quickly replicate what could be a complicated piece at a very quick rate, when compared to other conventional tagging methods.
Stencil graffiti subculture has been around for the last thirty years. John Fekner is one of the first artists to place his work outdoors, starting in 1968. Fekner's stencil Wheels Over Indian Trails greeted motorists and international travelers arriving in New York City
Art Deco (/ˌɑrt ˈdɛkoʊ/), or deco, is an eclectic artistic and design style that began in Paris in the 1920s and flourished internationally throughout the 1930s and into the World War II era. The style influenced all areas of design, including architecture and interior design, industrial design, fashion and jewelry, as well as the visual arts such as painting, graphic arts and film. The term "art deco" was coined in 1966, after an exhibition in Paris, 'Les Années 25' sub-titled Art Deco, celebrating the 1925 Exposition Internationale des Arts Décoratifs et Industriels Modernes (International Exhibition of Modern Decorative and Industrial Arts) that was the culmination of style moderne in Paris. At its best, art deco represented elegance, glamour, functionality,and modernity. Art deco's linear symmetry was a distinct departure from the flowing asymmetrical organic curves of its predecessor style art nouveau; it embraced influences from many different styles of the early twentieth century, including neoclassical, constructivism, cubism, modernism and futurism and drew inspiration from ancient Egyptian and Aztec forms. Although many design movements have political or philosophical
Art medals are a well-known and highly collected form of small bronze sculpture, and are considered a form of exonumia. An artist who produces medals is known as a "medallist" (British English) or "medalist" (American English), which is unfortunately the same word used in sport and other areas (but not usually in military contexts) for the winner of a medal as an award. Medallists very often also design, or produce the dies for coins as well. In modern times medallists are mostly primarily sculptors of larger works, but in the past the number of medals and coins produced were sufficient to allow specialists who spent most of their career producing them. Medallists are also often confusingly referred to as "engravers" in reference works, referring to the "engraving" of dies, although this is often in fact not the technique used; however many also worked in engraving the technique in printmaking.
Art medals have been produced since the late Renaissance period, and, after some classical precedents and Late Medieval revivals, the form was essentially invented by Pisanello, who is credited with the first portrait medal, which has remained a very popular type. He cast them like bronze
Linocut is a printmaking technique, a variant of woodcut in which a sheet of linoleum (sometimes mounted on a wooden block) is used for the relief surface. A design is cut into the linoleum surface with a sharp knife, V-shaped chisel or gouge, with the raised (uncarved) areas representing a reversal (mirror image) of the parts to show printed. The linoleum sheet is inked with a roller (called a brayer), and then impressed onto paper or fabric. The actual printing can be done by hand or with a press.
Although linoleum as a floor covering dates to the 1860s, the linocut printing technique was used first by the artists of Die Brücke in Germany between 1905–13 where it had been similarly used for wallpaper printing. They initially described their prints as woodcuts however, which sounded more respectable.
As the material being carved has no particular direction to its grain and does not tend to split, it is easier to obtain certain artistic effects with lino than with most woods, although the resultant prints can lack the often angular grainy character of woodcuts and engravings. Lino is much easier to cut than wood, especially when heated, but the pressure of the printing process
Advertising is a form of communication for marketing and used to encourage or persuade an audience (viewers, readers or listeners; sometimes a specific group) to continue or take some new action. Most commonly, the desired result is to drive consumer behavior with respect to a commercial offering, although political and ideological advertising is also common. The purpose of advertising may also be to reassure employees or shareholders that a company is viable or successful. Advertising messages are usually paid for by sponsors and viewed via various traditional media; including mass media such as newspaper, magazines, television commercial, radio advertisement, outdoor advertising or direct mail; or new media such as blogs, websites or text messages.
Commercial advertisers often seek to generate increased consumption of their products or services through "branding," which involves the repetition of an image or product name in an effort to associate certain qualities with the brand in the minds of consumers. Non-commercial advertisers who spend money to advertise items other than a consumer product or service include political parties, interest groups, religious organizations and
Carrara marble, sometimes mistakenly called Carrera marble, is a type of white or blue-grey marble popular for use in sculpture and building decor. It is quarried at the city of Carrara in the province of Massa and Carrara in modern day Tuscany, Italy.
The marble quarries were monitored by the Cybo and Malaspina families who ruled over Massa and Carrara during the 17th and 18th centuries. The family created the Office of Marble in 1564 to regulate the marble mining industry. The city of Massa, in particular, saw much of its plan redesigned (new roads, plazas, intersections, pavings) in order to make it worthy of an Italian country's capital. Following the extinction of the Cybo-Malaspina family, the state was ruled by the House of Austria and management of the mines rested with them. The Basilica of Massa is built entirely of Carrara marble and the old Ducal Palace of Massa was used to showcase the precious stone.
Carrara marble has been used since the time of Ancient Rome; the Pantheon and Trajan's Column in Rome are constructed of it. Many sculptures of the Renaissance, such as Michelangelo's David (1501-04), were carved from Carrara marble. For Michelangelo at least, Carrara
Chocolate /ˈtʃɒklət/ is a raw or processed food produced from the seed of the tropical Theobroma cacao tree. Cacao has been cultivated for at least three millennia in Mexico, Central and South America. Its earliest documented use is around 1100 BC. The majority of the Mesoamerican people made chocolate beverages, including the Aztecs, who made it into a beverage known as xocolātl [ʃo'kolaːt͡ɬ], a Nahuatl word meaning "bitter water". The seeds of the cacao tree have an intense bitter taste, and must be fermented to develop the flavor.
After fermentation, the beans are dried, then cleaned, and then roasted, and the shell is removed to produce cacao nibs. The nibs are then ground to cocoa mass, pure chocolate in rough form. Because this cocoa mass usually is liquefied then molded with or without other ingredients, it is called chocolate liquor. The liquor also may be processed into two components: cocoa solids and cocoa butter. Unsweetened baking chocolate (bitter chocolate) contains primarily cocoa solids and cocoa butter in varying proportions. Much of the chocolate consumed today is in the form of sweet chocolate, combining cocoa solids, cocoa butter or other fat, and sugar. Milk
Gauze is a thin, translucent fabric with a loose open weave.
Gauze was traditionally woven in Palestine and the English word is said to derive from the place name for Gaza (Arabic: غزة ghazza), a center of weaving in the region. Despite a prohibition on trade with non-Christians from religious authorities in medieval Europe, a fine type of silk known as gazzatum was imported from Gaza as early as the 13th century. Though members of religious orders in Europe were forbidden to wear it, the fabric won a place for itself and emerged into modern life as gauze.
According to the French government's online etymology dictionary, the English form of the word derived from the French gaze, whose ultimate origin is uncertain, but is often attributed to the Arabic and Persian word qazz meaning "raw silk", which itself derived from the name of Gaza. The same source says the existence of "an ancient textile industry in Gaza is not assured," and it is not known how the word entered into widespread use in European languages, with examples of first usages cited being the medieval latin forms garza in Bologna in 1250 and gazzatum in Budapest in 1279.
Gauze was originally made of silk and was used
An LED display is a flat panel display, which uses light-emitting diodes as a video display. An LED panel is a small display, or a component of a larger display. They are typically used outdoors in store signs and billboards, and in recent years have also become commonly used in destination signs on public transport vehicles or even as part of transparent glass area. LED panels are sometimes used as form of lighting, for the purpose of general illumination, task lighting, or even stage lighting rather than display.
There are two types of LED panels: conventional (using discrete LEDs) and surface-mounted device (SMD) panels. Most outdoor screens and some indoor screens are built around discrete LEDs, also known as individually mounted LEDs. A cluster of red, green, and blue diodes is driven together to form a full-color pixel, usually square in shape. These pixels are spaced evenly apart and are measured from center to center for absolute pixel resolution. The largest LED display in the world is over 500 meters long and is located in Suzhou, China, covering the Yuanrong Times Square. The largest LED television in the world is the Center Hung Video Display at Cowboys Stadium, which
Paint is any liquid, liquefiable, or mastic composition which, after application to a substrate in a thin layer, is converted to a solid film. It is most commonly used to protect, color or provide texture to objects.
In 2011, South African archeologists reported finding a 100,000 year old human-made ochre-based mixture which may have been used like paint. Cave paintings drawn with red or yellow ochre, hematite, manganese oxide, and charcoal may have been made by early Homo sapiens as long as 40,000 years ago.
Ancient colored walls at Dendera, Egypt, which were exposed for years to the elements, still possess their brilliant color, as vivid as when they were painted about 2,000 years ago. The Egyptians mixed their colors with a gummy substance, and applied them separate from each other without any blending or mixture. They appeared to have used six colors: white, black, blue, red, yellow, and green. They first covered the area entirely with white then traced the design in black, leaving out the lights of the ground color. They used minium for red, and generally of a dark tinge.
Pliny mentions some painted ceilings in his day in the town of Ardea, which had been done prior to the
Stucco or render is a material made of an aggregate, a binder, and water. Stucco is applied wet and hardens to a very dense solid. It is used as decorative coating for walls and ceilings and as a sculptural and artistic material in architecture. Stucco may be used to cover less visually appealing construction materials such as concrete, cinder block, or clay brick and adobe.
The difference in nomenclature between stucco, plaster, and mortar is based more on use than composition. Until the later part of the nineteenth century, it was common that plaster, which was used inside a building, and stucco, which was used outside, would consist of the same primary materials: lime and sand (which are also used in mortar). Animal or plant fibers were often added for additional strength. In the later part of the nineteenth century, Portland cement was added with increasing frequency in an attempt to improve its durability. At the same time, traditional lime plasters were being replaced by gypsum plaster.
Traditional stucco is made of lime, sand, and water. Modern stucco is made of Portland cement, sand, and water. Lime is added to increase the permeability and workability of modern stucco.
Iron (AE /ˈaɪərn/ EYE-ər-n, BE /ˈaɪən/ EYE-ən) is a chemical element with the symbol Fe (from Latin: ferrum) and atomic number 26. It is a metal in the first transition series. It is the most common element (by mass) forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust. Iron's very common presence in rocky planets like Earth is due to its abundant production as a result of fusion in high-mass stars, where the production of nickel-56 (which decays to the most common isotope of iron) is the last nuclear fusion reaction that is exothermic. This causes radioactive nickel to become the last element to be produced before collapse of a supernova leads to the explosive events that scatter this precursor radionuclide of iron abundantly into space.
Like other group 8 elements, iron exists in a wide range of oxidation states, −2 to +6, although +2 and +3 are the most common. Elemental iron occurs in meteoroids and other low oxygen environments, but is reactive to oxygen and water. Fresh iron surfaces appear lustrous silvery-gray, but oxidize in normal air to give iron oxides, also known as rust. Unlike
Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives and food glazing agents. They are also prized as an important source of raw materials for organic synthesis, and as constituents of incense and perfume. Plant resins have a very long history that was documented in ancient Greece by Theophrastus, in ancient Rome by Pliny the Elder, and especially in the resins known as frankincense and myrrh, prized in ancient Egypt. These were highly prized substances, and required as incense in some religious rites. Amber is a hard fossilized resin from ancient trees.
More broadly, the term "resin" also encompasses a great many synthetic substances of similar mechanical properties (thick liquids that harden into transparent solids), as well as shellacs of insects of the superfamily Coccoidea.
Other liquid compounds found in plants or exuded by plants, such as sap, latex, or mucilage, are sometimes confused with resin, but are not chemically the same. Saps, in particular, serve a nutritive function that resins do not.
Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal. However, since "bronze" is a somewhat imprecise term, and historical pieces have variable compositions, in particular with an unclear boundary with brass, modern museum and scholarly descriptions of older objects increasingly use the more cautious and inclusive term "copper alloy" instead. Historically the term latten was used for such alloys.
The word bronze is borrowed from French: bronze, itself borrowed from Italian: bronzo (compare Medieval Latin: bronzium), whose origin is unclear. It might be connected with Venetian: bronza "glowing coals", or German: Brunst "fire", but it could equally go back to, or be influenced by, the Latin name Brundisium of the city of Brindisi (aes Brundusinum, meaning "copper of Brindisi", is attested in Pliny). However, perhaps it is ultimately taken from the Persian word for brass, birinj.
The discovery of bronze enabled people to create metal objects which were better than previously possible. Tools, weapons, armor, and
Hessian ( /ˈhɛsi.ən/), or burlap in the US, is a woven fabric usually made from skin of the jute plant or sisal fibres, or may be combined with other vegetable fibres to make rope, nets, and similar products. Gunny cloth is similar.
Hessian, a dense woven fabric, has been historically produced as a coarse fabric, but more recently it is being used in a refined state known simply as jute as an ecofriendly material for bags, rugs, and other products.
The name "burlap" appears to be of unknown origin. The name "hessian" is attributed to the use of the fabric, initially, as part of the uniform of soldiers from the German state of Hesse who were called "Hessians."
Hessian was first exported from India in the early 19th century. It was traditionally used as backing for linoleum, rugs and carpet.
Hessian is often used to make sacks and bags to ship goods like coffee beans; these can be described as gunny sacks. It is breathable and thus resists condensation and associated spoilage of the contents. It is also durable enough to withstand rough handling in transit; these properties have also led to its use for temporary protection as wet covering to prevent rapid moisture loss in setting of
A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting. Appearing as practical electronic components in 1962, early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness.
When a light-emitting diode is forward-biased (switched on), electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence and the color of the light (corresponding to the energy of the photon) is determined by the energy gap of the semiconductor. An LED is often small in area (less than 1 mm), and integrated optical components may be used to shape its radiation pattern. LEDs present many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. LEDs powerful enough for room lighting are relatively expensive and require more precise current and heat management than compact fluorescent lamp sources of comparable
Marble is a non-foliated metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite.
Geologists use the term "marble" to refer to metamorphosed limestone; however stonemasons use the term more broadly to encompass unmetamorphosed limestone.
Marble is commonly used for sculpture and as a building material.
The word "marble" derives from the Greek "μάρμαρον" (mármaron), from "μάρμαρος" (mármaros), "crystalline rock", "shining stone", perhaps from the verb "μαρμαίρω" (marmaírō), "to flash, sparkle, gleam". This stem is also the basis for the English word marmoreal, meaning "marble-like."
Whilst the English term resembles the French marbre, most other European languages (e.g. Spanish mármol, Italian marmo, Portuguese mármore, German, Norwegian, Danish and Swedish marmor, Armenian marmar, Dutch marmer, Polish marmur, Turkish mermer, Czech mramor and Russian мрáмор ) follow the original Greek.
Marble is a rock resulting from metamorphism of sedimentary carbonate rocks, most commonly limestone or dolomite rock. Metamorphism causes variable recrystallization of the original carbonate mineral grains.
The resulting marble rock is typically composed of
Pen and ink refers to a technique of drawing or writing, in which colored (this includes black) ink is applied to paper using a pen or other stylus. It may be used as a medium for sketches, or for finished works of art. Pen and ink also lends itself to fine writing and calligraphy.
The pen and ink art type is commonly used in drawing, and comic book first-editions. The main
aspect of the Pen and Ink art type is to create fine, nice lines without having paint drip, or markers bleed through, or have to erase pencil marks.
Platinum prints, also called platinotypes, are photographic prints made by a monochrome printing process that provides the greatest tonal range of any printing method using chemical development.
Platinum prints are made by photographers and favored by collectors because of their tonal range, the surface quality and their permanence. A platinum print provides a broad scale of tones from black to white. The platinum tones range from warm black, to reddish brown, to expanded mid-tone grays that are unobtainable in silver prints.
Unlike the silver print process, platinum lies on the paper surface, while silver lies in a gelatin or albumen emulsion that coats the paper. As a result, since no gelatin emulsion is used, the final platinum image is absolutely matte with a deposit of platinum (and/or palladium, its sister element which is also used in most platinum photographs) absorbed slightly into the paper.
Platinum prints are the most durable of all photographic processes. The platinum group metals are very stable against chemical reactions that might degrade the print—even more stable than gold. It is estimated that a platinum image, properly made, can last thousands of years. Some of
A rope is a linear collection of plies, yarns or strands which are twisted or braided together in order to combine them into a larger and stronger form. Ropes have tensile strength and so can be used for dragging and lifting, but are far too flexible to provide compressive strength. As a result, they cannot be used for pushing or similar compressive applications. Rope is thicker and stronger than similarly constructed cord, line, string, and twine.
Rope may be constructed of any long, stringy, fibrous material, but generally is constructed of certain natural or synthetic fibres. Synthetic fibre ropes are significantly stronger than their natural fibre counterparts, but also possess certain disadvantages, including slipperiness.
Common natural fibres for rope are manila hemp, hemp, linen, cotton, coir, jute, straw, and sisal. Synthetic fibres in use for rope-making include polypropylene, nylon, polyesters (e.g. PET, LCP, HDPE, Vectran), polyethylene (e.g. Dyneema and Spectra), Aramids (e.g. Twaron, Technora and Kevlar) and acrylics (e.g. Dralon). Some ropes are constructed of mixtures of several fibres or use co-polymer fibres. Rope can also be made out of metal. Ropes have been
Screen printing is a printing technique that uses a woven mesh to support an ink-blocking stencil. The attached stencil forms open areas of mesh that transfer ink or other printable materials which can be pressed through the mesh as a sharp-edged image onto a substrate. A fill blade or squeegee is moved across the screen stencil, forcing or pumping ink into the mesh openings for transfer by capillary action during the squeegee stroke.
Screen printing is also a stencil method of print making in which a design is imposed on a screen of polyester or other fine mesh, with blank areas coated with an impermeable substance, and ink is forced into the mesh openings of the mesh by the fill blade or squeegee and onto the printing surface during the squeegee stroke. It is also known as silkscreen, serigraphy, and serigraph printing. A number of screens can be used to produce a multicoloured image.
There are various terms used for what is essentially the same technique. Traditionally the process was called screen printing or silkscreen printing because silk was used in the process prior to the invention of polyester mesh. Currently, synthetic threads are commonly used in the screen printing
A vase ( /ˈvɑːz/, /ˈveɪs/, or /ˈveɪz/) is an open container, often used to hold cut flowers. It can be made from a number of materials including ceramics and glass. The vase is often decorated and thus used to extend the beauty of its contents.
Vases are defined as having a certain anatomy. Lowest is the foot, a distinguishable base to the piece. The design of the base may be bulbous, flat, carinate, or another shape. Next, the body, which forms the main and often largest portion of the piece. Resting atop the body is the shoulder, where the body curves inward. Then the neck, where the vase is given more height. Lastly, the lip, where the vase flares back out at the top. All these attributes can be seen in the picture at right. Many vases are also given handles. Today, the shapes of vases have evolved from the conventional ones to modern designs and shapes.
The vase has also developed as an art medium unto itself. The ancient Greeks famously used vases to depict scenes. It has since been developed and in 2003 the winner of the Turner Prize was Grayson Perry, for vase art.
Artworks:Samuel Renshaw, Sicklegrinder Ridgeway, August 1857
The ambrotype (from Ancient Greek: ἀνβροτός — “immortal”, and τύπος — “impression”) or amphitype is a photograph that creates a positive image on a sheet of glass using the wet plate collodion process. In the United States, ambrotypes first came into use in the early 1850s. The wet plate collodion process was invented just a few years before that by Frederick Scott Archer, but ambrotypes used the plate image as a positive, instead of a negative. In 1854, James Ambrose Cutting of Boston took out several patents relating to the process and may be responsible for coining the term "ambrotype".
In the United Kingdom it was called collodion positive: one side of a very clean glass plate is covered with a thin layer of collodion, then dipped in a silver nitrate solution. The plate is exposed to the subject while still wet. (Exposure times vary from five to sixty seconds or more depending on the amount of available light.) The plate is then developed and fixed. The resulting negative, when viewed by reflected light against a black background, appears to be a positive image: the clear areas look black, and the exposed, opaque areas appear light. This effect is achieved by coating one side
Charcoal is the dark grey residue consisting of carbon, and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis, the heating of wood or other substances in the absence of oxygen (see pyrolysis, char and biochar). It is usually an impure form of carbon as it contains ash; however, sugar charcoal is among the purest forms of carbon readily available, particularly if it is not made by heating but by a dehydration reaction with sulfuric acid to minimise introducing new impurities, as impurities can be removed from the sugar in advance. The resulting soft, brittle, lightweight, black, porous material resembles coal.
Historically, production of wood charcoal in districts where there is an abundance of wood dates back to a very ancient period, and generally consists of piling billets of wood on their ends so as to form a conical pile, openings being left at the bottom to admit air, with a central shaft to serve as a flue. The whole pile is covered with turf or moistened clay. The firing is begun at the bottom of the flue, and gradually spreads outwards and upwards. The success
Gelatin silver printing was the dominant photographic process from the period of their introduction in the 1880s until the 1960s when they were eclipsed by consumer color photography. The gelatin silver or black-and-white print is thus a primary form of visual documentation in the 20th century. Its widespread use in applications as wide-ranging as fine art, snap shots, and document reproduction led to an extraordinary variety of papers with a wide range of available surface texture and gloss, and paper thickness.
Gelatin silver print paper was made as early as 1874 on a commercial basis, but it was poor quality because the dry-plate emulsion was coated onto the paper only as an afterthought. Coating machines for the production of continuous rolls of sensitized paper were in use by the mid-1880s, though widespread adoption of gelatin silver print materials did not occur until the 1890s. The earliest papers had no baryta layer, and it was not until the 1890s that baryta coating became a commercial operation, first in Germany, in 1894, and then taken up by Kodak by 1900.
Although the baryta layer plays an important part in the manufacture of smooth and glossy prints, the baryta paper
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae (or Gramineae) family, as well as the sedges (Cyperaceae) and the rushes (Juncaceae). The true grasses include cereals, bamboo and the grasses of lawns (turf) and grassland. Sedges include many wild marsh and grassland plants, and some cultivated ones such as water chestnut (Eleocharis dulcis) and papyrus sedge (Cyperus papyrus). Uses for graminoids include food (as grain, sprouted grain, shoots or rhizomes), drink (beer, whisky, vodka), pasture for livestock, thatch, paper, fuel, clothing, insulation, construction, sports turf, basket weaving and many others.
Graminoids are among the most versatile life forms. They became widespread toward the end of the Cretaceous period, and fossilized dinosaur dung (coprolites) have been found containing phytoliths of a variety of grasses that include grasses that are related to modern rice and bamboo. Grasses have adapted to conditions in lush rain forests, dry deserts, cold mountains and even intertidal habitats, and are now the most widespread plant type; grass is a
Lace is an openwork fabric, patterned with open holes in the work, made by machine or by hand. The holes can be formed via removal of threads or cloth from a previously woven fabric, but more often open spaces are created as part of the lace fabric. Lace-making is an ancient craft. True lace was not made until the late 15th and early 16th centuries. A true lace is created when a thread is looped, twisted or braided to other threads independently from a backing fabric.
Originally linen, silk, gold, or silver threads were used. Now lace is often made with cotton thread, although linen and silk threads are still available. Manufactured lace may be made of synthetic fiber. A few modern artists make lace with a fine copper or silver wire instead of thread.
There are many types of lace, classified by how they are made. These include:
The word lace is from Middle English, from Old French las, noose, string, from Vulgar Latin *laceum, from Latin laqueus, noose; probably akin to lacere, to entice, ensnare.
In the late 16th century there was a rapid development in the field of lace. There was an openwork fabric where combinations of open spaces and dense textures form designs. These forms of
Whether trasy, avant-garde, academic, or political, the magazine cover provides a snapshot of contemporary ideas, politics, aesthetics and trends.
While other cultural products - like vinyl records and video cassettes - come and go, the magazine has enjoyed more than a century of steady success. A copy of Vogue or Vanity Fair from the early years of the 20th century stands comparison with its counterpart today...Despite the consistency of the magazine format, there have been significant changes in the way that magazines have been produced. Colour printing - once reserved for the cover - became much more affordable from the 1950's...The refinement of small hand-held cameras in the 1920's, for instance, meant that the explosive drama of war could be captured photographically for the first time... ...Commentator, charting the rise of other media, have repeatedly prohesied the magazine's demise. The success of television in the 1950's and 1960's, it was said, would kill off popular magazines...In the early 1990's another generation of soothsayers predicted that the application of digital technology would kill off print. All our information needs would be delivered through portable
Offset printing is a commonly used printing technique in which the inked image is transferred (or "offset") from a plate to a rubber blanket, then to the printing surface. When used in combination with the lithographic process, which is based on the repulsion of oil and water, the offset technique employs a flat (planographic) image carrier on which the image to be printed obtains ink from ink rollers, while the non-printing area attracts a water-based film (called "fountain solution"), keeping the non-printing areas ink-free.
Development of the offset press came in two versions: in 1875 by Robert Barclay of England for printing on tin, and in 1903 by Ira Washington Rubel of the United States for printing on paper.
Lithography was initially created to be a low cost method of reproducing artwork. This printing process was limited to use on flat, porous surfaces because the printing plates were produced from limestone. In fact, the word 'lithograph' historically means "an image from stone." Tin cans were popular packaging materials in the 19th century, but transfer technologies were required before the lithographic process could be used to print on the tin.
The first rotary offset
Artworks:The Winged Heart of Valentine's Brilliant Desires
Oil pastel (also called wax oil crayon) is a painting and drawing medium with characteristics similar to pastels and wax crayons. Unlike "soft" or "French" pastel sticks, which are made with a gum or methyl cellulose binder, oil pastels consist of pigment mixed with a non-drying oil and wax binder. The surface of an oil pastel painting is therefore less powdery, but more difficult to protect with a fixative. Oil pastels provide a harder edge than "soft" or "French" pastels but are more difficult to blend.
At the end of World War I, Kanae Yamamoto proposed an overhaul of the Japanese education system. He thought that it had been geared too much towards uncritical absorption of information by imitation and wanted to promote a less restraining system, a vision he expounded in his book Theory of self-expression which described the Jiyu-ga method, "learning without a teacher". Teachers Rinzo Satake and his brother-in-law Shuku Sasaki read Yamamoto's work and became fanatical supporters. They became keen to implement his ideas by replacing the many hours Japanese children had to spend drawing ideograms with black Indian ink with free drawing hours, filled with as much as colour as
A photograph or photo is an image created by light falling on a light-sensitive surface, usually photographic film or an electronic image such as a CCD or a CMOS chip. Most photographs are created using a camera, which uses a lens to focus the scene's visible wavelengths of light into a reproduction of what the human eye would see. The process and practice of creating photographs is called photography. The word "photograph" was coined in 1839 by Sir John Herschel and is based on the Greek φῶς (phos), meaning "light", and γραφή (graphê), meaning "drawing, writing", together meaning "drawing with light".
The first permanent photograph was made in 1822 by a French inventor, Joseph Nicéphore Niépce, building on a discovery by Johann Heinrich Schultz (1724): that a silver and chalk mixture darkens under exposure to light. Niépce and Louis Daguerre refined this process. Daguerre discovered that exposing the silver first to iodine vapor, before exposure to light, and then to mercury fumes after the photograph was taken, could form a latent image; bathing the plate in a salt bath then fixes the image. These ideas led to the famous daguerreotype.
The daguerreotype had its problems, notably
Plaster is a building material used for coating walls and ceilings. Plaster starts as a dry powder similar to mortar or cement and like those materials it is mixed with water to form a paste which liberates heat and then hardens. Unlike mortar and cement, plaster remains quite soft after setting, and can be easily manipulated with metal tools or even sandpaper. These characteristics make plaster suitable for a finishing, rather than a load-bearing material.
The term plaster can refer to gypsum plaster (also known as plaster of Paris), lime plaster, or cement plaster.
Gypsum plaster, or plaster of Paris, is produced by heating gypsum to about 300°F (150 °C):
When the dry plaster powder is mixed with water, it re-forms into gypsum. The setting of unmodified plaster starts about 10 minutes after mixing and is complete in about 45 minutes; but not fully set for 72 hours. If plaster or gypsum is heated above 392°F (200°C), anhydrite is formed, which will also re-form as gypsum if mixed with water.
A large gypsum deposit at Montmartre in Paris led gypsum plaster to be commonly known as "plaster of Paris".
Plasterers often use gypsum to simulate the appearance of surfaces of wood, stone,
Natural rubber, also called India Rubber or Caoutchouc, is a mixture of organic compound polyisoprene and small amounts of other organic compounds as well as water. This polymer is the main component. This material is classified as an elastomer (an elastic polymer). It is derived from latex, a milky colloid produced by some plants. The plants are ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined into a usable rubber. Polyisoprene can also be produced synthetically. Natural rubber is used extensively in many applications and products, as is synthetic rubber. It is normally very stretchy and flexible and extremely waterproof.
The commercial source of natural rubber latex is the Pará rubber tree (Hevea brasiliensis), a member of the spurge family, Euphorbiaceae. This species is widely used because it responds to wounding by producing more latex.
Other plants containing latex include gutta-percha (Palaquium gutta), rubber fig (Ficus elastica), Panama rubber tree (Castilla elastica), spurges (Euphorbia spp.), lettuce, common dandelion (Taraxacum officinale), Russian dandelion (Taraxacum kok-saghyz), Scorzonera
In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5% to 11% chromium content by mass.
Stainless steel does not readily corrode, rust or stain with water as ordinary steel does, but despite the name it is not fully stain-proof, most notably under low oxygen, high salinity, or poor circulation environments. It is also called corrosion-resistant steel or CRES when the alloy type and grade are not detailed, particularly in the aviation industry. There are different grades and surface finishes of stainless steel to suit the environment the alloy must endure. Stainless steel is used where both the properties of steel and resistance to corrosion are required.
Stainless steel differs from carbon steel by the amount of chromium present. Unprotected carbon steel rusts readily when exposed to air and moisture. This iron oxide film (the rust) is active and accelerates corrosion by forming more iron oxide, and due to the dissimilar size of the iron and iron oxide molecules (iron oxide is larger) these tend to flake and fall away. Stainless steels contain sufficient chromium to form a passive film of
Giclée ( /ʒiːˈkleɪ/ zhee-KLAY or /dʒiːˈkleɪ/), is a neologism coined in 1991 by printmaker Jack Duganne for fine art digital prints made on inkjet printers. The name originally applied to fine art prints created on IRIS printers in a process invented in the late 1980s but has since come to mean any inkjet print. It is often used by artists, galleries, and print shops to denote high quality printing but since it is an unregulated word it has no associated warranty of quality.
The word giclée was created by Jack Duganne, a printmaker working at Nash Editions. He wanted a name for the new type of prints they were producing on the IRIS printer, a large-format, high-resolution industrial prepress proofing inkjet printer they had adapted for fine-art printing. He was specifically looking for a word that would not have the negative connotations of "inkjet" or "computer generated". It is based on the French word gicleur, which means "nozzle" (the verb form gicler means "to squirt, spurt, or spray").
Beside its original association with IRIS prints, the word giclée has come to be associated with other types of inkjet printing including processes that use fade-resistant, archival inks
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz.
The second most common form of sand is calcium carbonate, for example aragonite, which has mostly been created, over the past half billion years, by various forms of life, like coral and shellfish. It is, for example, the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years, like the Caribbean.
In terms of particle size as used by geologists, sand particles range in diameter from 0.0625 mm (or ⅟16 mm) to 2 mm. An individual particle in this range size is termed a sand grain. Sand grains are between gravel (with particles ranging from 2 mm up to 64 mm) and silt (particles smaller than 0.0625 mm down to 0.004 mm). The size specification between sand and gravel has remained constant for more than a century, but particle diameters as small as 0.02 mm were considered sand
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at temperatures above 0 °C (273.15 K, 32 °F) at sea level, but it often co-exists on Earth with its solid state, ice, and gaseous state (water vapor or steam). Water also exists in a liquid crystal state near hydrophilic surfaces.
Water covers 71% of the Earth's surface, and is vital for all known forms of life. On Earth, 96.5% of the planet's water is found in oceans, 1.7% in groundwater, 1.7% in glaciers and the ice caps of Antarctica and Greenland, a small fraction in other large water bodies, and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation. Only 2.5% of the Earth's water is freshwater, and 98.8% of that water is in ice and groundwater. Less than 0.3% of all freshwater is in rivers, lakes, and the atmosphere, and an even smaller amount of the Earth's freshwater (0.003%) is contained within biological bodies and manufactured products.
Water on Earth moves continually through the hydrological cycle of evaporation and transpiration
Fiberboard is a type of engineered wood product that is made out of wood fibers. Types of fiberboard (in order of increasing density) include particle board, medium-density fiberboard, and hardboard. Fiberboard is sometimes used as a synonym for particle board, but particle board usually refers to low-density fiberboard. Plywood is not a type of fiberboard, as it is made of thin sheets of wood, not wood fibers or particles. Fiberboard, particularly medium-density fiberboard (MDF), is heavily used in the furniture industry. For pieces that will be visible, a veneer of wood is often glued onto fiberboard to give it the appearance of conventional wood.
Fiberboard is also used in the auto industry to create free-form shapes such as dashboards, rear parcel shelves, and inner door shells. These pieces are usually covered with a skin, foil, or fabric such as cloth, suede, leather, or polyvinyl chloride.
Urea-formaldehyde (UF) resins are dominantly used in the medium density fiberboard (MDF) industry because of their low cost and fast curing characteristics. However, pressures on the use of UF resins are mounting steadily due to potential problems associated with formaldehyde emission. On
Ivory is a term for dentine, which constitutes the bulk of the teeth and tusks of animals, when used as a material for art or manufacturing. Ivory has been important since ancient times for making a range of items, from ivory carvings to false teeth, fans, dominoes, joint tubes, piano keys and billiard balls. Elephant ivory has been the most important source, but ivory from many species including the hippopotamus, walrus, pig, mammoth, sperm whale, and narwhal has been used. The word ultimately derives from the Ancient Egyptian âb, âbu "elephant", through the Latin ebor- or ebur.
The use and trade of elephant ivory has become controversial because it has contributed to seriously declining elephant populations in many countries. In 1975 the Asian elephant was placed on Appendix One of the Convention on International Trade in Endangered Species (CITES) which prevents international trade between member countries. The African elephant was placed on Appendix One in January 1990. Since then some southern African countries have had their populations of elephants "downlisted" to Appendix Two allowing sale of some stockpiles.
Ivory has availed itself to many ornamental and practical uses.
Lead ( /ˈlɛd/) is a chemical element in the carbon group with symbol Pb (from Latin: plumbum) and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed to air. Lead has a shiny chrome-silver luster when it is melted into a liquid.
Lead is used in building construction, lead-acid batteries, bullets and shots, weights, as part of solders, pewters, fusible alloys, and as a radiation shield. Lead has the highest atomic number of all of the stable elements, although the next higher element, bismuth, has a half-life that is so long (much longer than the age of the universe) that it can be considered stable. Its four stable isotopes have 82 protons, a magic number in the nuclear shell model of atomic nuclei.
Lead, at certain contact degrees, is a poisonous substance to animals as well as for human beings. It damages the nervous system and causes brain disorders. Excessive lead also causes blood disorders in mammals. Like the element mercury, another heavy metal, lead is a neurotoxin that accumulates both in soft tissues
Butter sculptures often depict animals, people, buildings and other objects. They are best known as attractions at state fairs in the United States as lifesize cows and people, but can also be found on banquet tables and even small decorative butter pats. The earliest documented butter sculptures date from 1536 Europe where they were used on banquet tables. The earliest pieces in the modern sense as public art date from ca. 1870s America, created by Caroline Shawk Brooks, a farm woman from Helena, Arkansas. The heyday of butter sculpturing was about 1890-1930, but butter sculptures are still a popular attraction at agricultural fairs, banquet tables and as decorative butter patties.
The history of carving food into sculptured objects is ancient. Archaeologists have found bread and pudding molds of animal and human shapes at sites from Babylon to Roman Britain. Butter sculpture is an ancient Tibetan Buddhist tradition; yak butter and dye are still used to create temporary symbols for the Tibetan New Year and other religious celebrations.
During the Renaissance and Baroque periods molding food was commonly done for wealthy banquets. It was during this period that the earliest known
Collage (From the French: coller, to glue, French pronunciation: [kɔ.laːʒ]) is a technique of art production, primarily used in the visual arts, where the artwork is made from an assemblage of different forms, thus creating a new whole.
A collage may sometimes include newspaper clippings, ribbons, bits of colored or handmade papers, portions of other artwork or texts, photographs and other found objects, glued to a piece of paper or canvas. The origins of collage can be traced back hundreds of years, but this technique made a dramatic reappearance in the early 20th century as an art form of novelty.
The term collage derives from the French "coller" meaning "glue". This term was coined by both Georges Braque and Pablo Picasso in the beginning of the 20th century when collage became a distinctive part of modern art.
Techniques of collage were first used at the time of the invention of paper in China, around 200 BC. The use of collage, however, wasn't used by many people until the 10th century in Japan, when calligraphers began to apply glued paper, using texts on surfaces, when writing their poems.
The technique of collage appeared in medieval Europe during the 13th century. Gold
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking. Normally, the job is managed by a project manager, and supervised by a construction manager, design engineer, construction engineer or project architect.
For the successful execution of a project, effective planning is essential. Involved with the design and execution of the infrastructure in question must consider the environmental impact of the job, the successful scheduling, budgeting, construction site safety, availability of building materials, logistics, inconvenience to the public caused by construction delays and bidding, etc.
In general, there are four types of construction:
Each type of construction project requires a unique team to plan, design, construct and maintain the project.
Building construction is the process of adding structure to real property. The vast majority of building construction jobs are small renovations, such as addition of a room, or renovation of a bathroom. Often, the owner of the property acts as laborer, paymaster,
Copper ( /ˈkɒpər/ KOP-ər) is a chemical element with the symbol Cu (from Latin: cuprum) and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; a freshly exposed surface has a reddish-orange color. It is used as a conductor of heat and electricity, a building material, and a constituent of various metal alloys.
The metal and its alloys have been used for thousands of years. In the Roman era, copper was principally mined on Cyprus, hence the origin of the name of the metal as сyprium (metal of Cyprus), later shortened to сuprum. Its compounds are commonly encountered as copper(II) salts, which often impart blue or green colors to minerals such as turquoise and have been widely used historically as pigments. Architectural structures built with copper corrode to give green verdigris (or patina). Decorative art prominently features copper, both by itself and as part of pigments.
Copper(II) ions are water-soluble, where they function at low concentration as bacteriostatic substances, fungicides, and wood preservatives. In sufficient amounts, they are poisonous to higher organisms; at lower concentrations it is an
Diorite ( /ˈdaɪəraɪt/) is a grey to dark grey intermediate intrusive igneous rock composed principally of plagioclase feldspar (typically andesine), biotite, hornblende, and/or pyroxene. It may contain small amounts of quartz, microcline and olivine. Zircon, apatite, sphene, magnetite, ilmenite and sulfides occur as accessory minerals. It can also be black or bluish-grey, and frequently has a greenish cast. Varieties deficient in hornblende and other dark minerals are called leucodiorite. When olivine and more iron-rich augite are present, the rock grades into ferrodiorite, which is transitional to gabbro. The presence of significant quartz makes the rock type quartz-diorite (>5% quartz) or tonalite (>20% quartz), and if orthoclase (potassium feldspar) is present at greater than ten percent the rock type grades into monzodiorite or granodiorite. Diorite has a medium grain size texture, occasionally with porphyry.
Diorites may be associated with either granite or gabbro intrusions, into which they may subtly merge. Diorite results from partial melting of a mafic rock above a subduction zone. It is commonly produced in volcanic arcs, and in cordilleran mountain building such as in
Gravel /ˈɡrævəl/ is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments. Gravel is sub-categorized by the Udden-Wentworth scale into granular gravel (>2 to 4 mm or 0.079 to 0.16 in) and pebble gravel (>4 to 64 mm or 0.2 to 2.5 in). One cubic yard of gravel typically weighs about 3000 pounds (or a cubic metre is about 1,800 kilograms).
Gravel is an important commercial product, with a number of applications. Many roadways are surfaced with gravel, especially in rural areas where there is little traffic. Globally, far more roads are surfaced with gravel than with concrete or tarmac; Russia alone has over 400,000 km (250,000 mi) of gravel roads. Both sand and small gravel are also important for the manufacture of concrete.
Large gravel deposits are a common geological feature, being formed as a result of the weathering and erosion of rocks. The action of rivers and waves tends to pile up gravel in large accumulations. This can sometimes result in gravel becoming compacted and concreted into the sedimentary rock called conglomerate. Where natural gravel deposits are insufficient for human
Artworks:Objet Surrealiste et fonctionnement symbolique le soulier de Gala
Mixed media, in visual art, refers to an artwork in the making of which more than one medium has been employed.
There is an important distinction between "mixed-media" artworks and "multimedia art". Mixed media tends to refer to a work of visual art that combines various traditionally distinct visual art media. For example, a work on canvas that combines paint, ink, and collage could properly be called a "mixed media" work - but not a work of "multimedia art." The term multimedia art implies a broader scope than mixed media, combining visual art with non-visual elements (such as recorded sound, for example) or with elements of the other arts (such as literature, drama, dance, motion graphics, music, or interactivity).Mixed media is for all ages.
When creating a painted or photographed work using mixed media it is important to choose the layers carefully and allow enough drying time between the layers to ensure the final work will have integrity. If many different media are used it is equally important to choose a sturdy foundation upon which the different layers are imposed.
A phrase sometimes used in relationship to mixed media is, "Fat over lean." In other words: "don't start
Paperboard is a thick paper based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker (usually over 0.25 mm/0.010 in or 10 points) than paper. According to ISO standards, paperboard is a paper with a basis weight (grammage) above 224 g/m, but there are exceptions. Paperboard can be single or multi-ply. Paperboard can be easily cut and formed, is lightweight, and because it is strong, is used in packaging. Another end-use would be graphic printing, such as book and magazine covers or postcards. Sometimes it is referred to as cardboard, which is a generic, lay term used to refer to any heavy paper pulp based board.
In 1817, the first paperboard carton was produced in England. Folding cartons first emerged around the 1860s and were shipped flat to save space, ready to be set up by customers when they were required. 1879 saw the development of mechanical die cutting and creasing of blanks. In 1911 the first kraft sulphate mill was built in Florida and in 1915 the gable top milk carton was patented and in 1935 the first dairy plant was observed using them. Ovenable paperboard was introduced in 1974.
Pitch is the name for any of a number of viscoelastic, solid polymers. Pitch can be made from petroleum products or plants. Petroleum-derived pitch is also called bitumen. Pitch produced from plants is also known as resin. Products made from plant resin are also known as rosin.
Pitch was traditionally used to help caulk the seams of wooden sailing vessels (see shipbuilding). Pitch was also used to waterproof wooden containers, and is sometimes still used in the making of torches. Petroleum-derived pitch is black in colour, hence the adjectival phrase, "pitch-black".
Tar pitch is a viscoelastic polymer. This means that even though it seems to be solid at room temperature and can be shattered with a hard impact, it is actually fluid and will flow over time, but extremely slowly. The pitch drop experiment taking place at University of Queensland is a long-term experiment which measures the flow of a piece of pitch over many years. For the experiment, pitch was put in a glass funnel and allowed to slowly drip out. Since the pitch was allowed to start dripping in 1930, only eight drops have fallen. It was calculated in the 1980s that the pitch in the experiment has a viscosity
Relief, or relievo rilievo, is a sculptural technique. The term relief is from the Latin verb levo, to raise. To create a sculpture in relief is to give the impression that the sculpted material has been raised above the background plane. What is actually performed when a relief is cut in from a flat surface of stone or wood is a lowering of the field, leaving the unsculpted parts seemingly raised. The technique involves considerable chiselling away of the background, which is a time-consuming exercise with little artistic effect if the lowered background is left plain, as is often the case. On the other hand, a relief saves forming the rear of a subject, and is less fragile and more securely fixed than a sculpture in the round, especially one of a standing figure where the ankles are a potential weak point, especially in stone. In other materials such as metal, clay, plaster stucco, ceramics or papier-mache the form can be just added to or raised up from the background, and monumental bronze reliefs are made by casting.
There are different degrees of relief depending on the degree of projection of the sculpted form from the field, for which the Italian appellations are still
Stoneware is a vitreous or semi-vitreous ceramic ware made primarily from non-refractory fire clay.
One widely-recognized definition is from the Combined Nomenclature of the European Communities, a European industry standard. It states:
"Stoneware, which, though dense, impermeable and hard enough to resist scratching by a steel point, differs from porcelain because it is more opaque, and normally only partially vitrified. It may be vitreous or semi-vitreous. It is usually coloured grey or brownish because of impurities in the clay used for its manufacture, and is normally glazed."
Formulations for stoneware vary considerably, although the vast majority will conform to: plastic fire clays 0–100%, ball clays 0–15%, quartz 0–30% feldspar and chamotte 0 –15%
Stoneware is generally once-fired. Maximum firing temperatures can vary significantly, from 1100 °C to 1300 °C depending on the flux content. Typically temperatures will be between 1180°C to 1280°C, the higher end of which equate to Bullers Rings 38 to 40 & Seger cones 4 to 8. To produce a better quality fired glaze finish twice firing can be used, and this can be especially important for formulations composed of highly
Artworks:Electronic Superhighway: Continental U.S., Alaska, Hawaii
Television (TV) is a telecommunication medium for transmitting and receiving moving images that can be monochrome (black-and-white) or colored, with or without accompanying sound. "Television" may also refer specifically to a television set, television programming, or television transmission.
The etymology of the word has a mixed Latin and Greek origin, meaning "far sight": Greek tele (τῆλε), far, and Latin visio, sight (from video, vis- to see, or to view in the first person).
Commercially available since the late 1920s, the television set has become commonplace in homes, businesses and institutions, particularly as a vehicle for advertising, a source of entertainment, and news. Since the 1950s, television has been the main medium for molding public opinion. Since the 1970s the availability of video cassettes, laserdiscs, DVDs and now Blu-ray Discs, have resulted in the television set frequently being used for viewing recorded as well as broadcast material. In recent years Internet television has seen the rise of television available via the Internet, e.g. iPlayer and Hulu.
Although other forms such as closed-circuit television (CCTV) are in use, the most common usage of the
Mezzotint is a printmaking process of the intaglio family, technically a drypoint method. It was the first tonal method to be used, enabling half-tones to be produced without using line- or dot-based techniques like hatching, cross-hatching or stipple. Mezzotint achieves tonality by roughening the plate with thousands of little dots made by a metal tool with small teeth, called a "rocker." In printing, the tiny pits in the plate hold the ink when the face of the plate is wiped clean. A high level of quality and richness in the print can be achieved.
The mezzotint printmaking method was invented by the German amateur artist Ludwig von Siegen (1609–c 1680). His earliest mezzotint print dates to 1642 and is a portrait of Amelia Elizabeth, Landgravine of Hesse-Kassel (or Hesse-Cassel) (right). This was made by working from light to dark. The rocker seems to have been invented by Prince Rupert of the Rhine, a famous cavalry commander in the English Civil War, who was the next to use the process, and took it to England. Sir Peter Lely saw the potential for using it to publicise his portraits, and encouraged a number of Dutch printmakers to come to England. The process was especially
Mohair /ˈmoʊhɛər/ usually refers to a silk-like fabric or yarn made from the hair of the Angora goat. The word "mohair" was adopted into English before 1570 from the Arabic: مخير mukhayyar, a type of haircloth, literally 'choice', from khayyara, 'he chose'. Mohair fiber is approximately 25–45 microns in diameter. It is one of the oldest textile fibers in use. It is both durable and resilient. It is notable for its high luster and sheen, which has helped give it the nickname the "Diamond Fiber," and is often used in fiber blends to add these qualities to a textile. Mohair takes dye exceptionally well. Mohair is warm in winter as it has great insulating properties, while remaining cool in summer due to its moisture wicking properties. It is durable, naturally elastic, flame resistant, crease resistant, and does not felt. It is considered to be a luxury fiber, like cashmere, angora and silk, and is usually more expensive than most wool that comes from sheep.
Mohair is composed mostly of keratin, a protein found in the hair, wool, horns and skin of all mammals. While it has scales like wool, the scales are not fully developed, merely indicated. Thus, mohair does not felt as wool
Quartz is an abundant mineral in the Earth's continental crust. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz, several of which are semi-precious gemstones. Throughout the world, varieties of quartz have been, since antiquity, the most commonly used minerals in the making of jewelry and hardstone carvings.
Quartz belongs to the trigonal crystal system. The ideal crystal shape is a six-sided prism terminating with six-sided pyramids at each end. In nature quartz crystals are often twinned, distorted, or so intergrown with adjacent crystals of quartz or other minerals as to only show part of this shape, or to lack obvious crystal faces altogether and appear massive. Well-formed crystals typically form in a 'bed' that has unconstrained growth into a void, but because the crystals must be attached at the other end to a matrix, only one termination pyramid is present. There are exceptions as doubly terminated crystals do occur. An occurrence in Herkimer County, New York is noted for these Herkimer diamonds with terminations at
Artificial leather is a fabric or finish intended to substitute for leather in fields such as upholstery, clothing, and fabrics, and other uses where a leather-like finish is required but the actual material is cost-prohibitive, unsuitable, or unusable for ethical reasons.
Under the name of artificial leather (not to be confused with the more modern Pleather) or American leather cloth, large quantities of a material having a more or less leather-like surface were once used, principally for upholstery purposes, such as the covering of chairs, lining the tops of writing desks and tables, and so on.
There was considerable diversity in the preparation of such materials. A common variety consisted of a web of calico coated with boiled linseed oil mixed with dryers and lampblack or other pigment. Several coats of this mixture were uniformly spread, smoothed and compressed on the cotton surface by passing it between metal rollers, and when the surface was required to possess a glossy enamel-like appearance, it received a finishing coat of copal varnish. A grained Morocco surface was given to the material by passing it between suitably embossed rollers.
Preparations of this kind have a
Casein ( /ˈkeɪs.ɪn/ or /ˈkeɪˌsiːn/, from Latin caseus, "cheese") is the name for a family of related phosphoproteins (αS1, αS2, β, κ). These proteins are commonly found in mammalian milk, making up 80% of the proteins in cow milk and between 20% and 45% of the proteins in human milk. Casein has a wide variety of uses, from being a major component of cheese, to use as a food additive, to a binder for safety matches. As a food source, casein supplies amino acids; carbohydrates; and two inorganic elements, calcium and phosphorus.
Casein contains a fairly high number of proline residues, which do not interact. There are also no disulfide bridges. As a result, it has relatively little tertiary structure. It is relatively hydrophobic, making it poorly soluble in water. It is found in milk as a suspension of particles called "casein micelles" which show only limited resemblance with surfactant-type micellae in a sense that the hydrophilic parts reside at the surface and they are spherical. However, in sharp contrast to surfactant micelles, the interior of a casein micelle is highly hydrated The caseins in the micelles are held together by calcium ions and hydrophobic interactions. Several
Ebony is a dense black wood, most commonly yielded by several species in the genus Diospyros, but ebony may also refer to other heavy, black (or dark colored) woods from unrelated species. Ebony is dense enough to sink in water. Its fine texture, and very smooth finish when polished, make it valuable as an ornamental wood. The word "ebony" derives from the Ancient Egyptian hbny, via the Ancient Greek ἔβενος (ébenos), by way of Latin and Middle English.
Species of ebony include Diospyros ebenum (Ceylon ebony), native to southern India and Sri Lanka; Diospyros crassiflora (Gaboon ebony), native to western Africa; and Diospyros celebica (Makassar ebony), native to Indonesia and prized for its luxuriant, multi-colored wood grain. Mauritius ebony, Diospyros tesselaria, was largely exploited by the Dutch in the 17th century. Some species in the genus Diospyros yield an ebony with similar physical properties, but striped rather than evenly black (Diospyros ebenum).
Ebony has a long history of use, with carved pieces having been found in Ancient Egyptian tombs. By the end of the 16th century, fine cabinets for the luxury trade were made of ebony in Antwerp. The wood's dense hardness lent
Artworks:Electronic Superhighway: Continental U.S., Alaska, Hawaii
An electronic component is any basic discrete device or physical entity in an electronic system used to affect electrons or their associated fields. Electronic components are mostly industrial products, available in a singular form and are not to be confused with electrical elements, which are conceptual abstractions representing idealized electronic components.
Electronic components have two or more electrical terminals (or leads). These leads connect, usually soldered to a printed circuit board, to create an electronic circuit (a discrete circuit) with a particular function (for example an amplifier, radio receiver, or oscillator). Basic electronic components may be packaged discretely, as arrays or networks of like components, or integrated inside of packages such as semiconductor integrated circuits, hybrid integrated circuits, or thick film devices. The following list of electronic components focuses on the discrete version of these components, treating such packages as components in their own right.
A component may be classified as passive, active, or electromechanic. The strict physics definition treats passive components as ones that cannot supply energy themselves, whereas
Medium-density fibreboard (MDF) is an engineered wood product formed by breaking down hardwood or softwood residuals into wood fibres, often in a defibrator, combining it with wax and a resin binder, and forming panels by applying high temperature and pressure. MDF is denser than plywood. It is made up of separated fibres, but can be used as a building material similar in application to plywood. It is stronger and much denser than normal particle board.
The name derives from the distinction in densities of fibreboard. Large-scale production of MDF began in the 1980s, in both North America and Europe.
Over time, the word "MDF" has become a generic name for any dry process fiber board. MDF density is typically between 500 kg/m (31 lbs/ft) and 1000 kg/m (62 lbs/ft). The range of density and classification as Light or Standard or High density board is a misnomer and confusing. Density of board when evaluated in relation to density of the fiber that goes in to making of the panel is important. A thick MDF panel at 700-720 density in case of softwood fiber panels may be considered as high density whereas a panel of same density when made of hard wood fibers is not so. The evolution of
Polystyrene (PS) ( /ˌpɒliˈstaɪriːn/) is an aromatic polymer made from the monomer styrene, a liquid petrochemical. Polystyrene is one of the most widely used plastics, the scale of its production being several billion kilograms per year. It is a colorless solid that is used, for example, in disposable cutlery, plastic models, CD and DVD cases, and smoke detector housings. Products made from foamed polystyrene are ubiquitous, for example packing materials, insulation, and foam drink cups. Its very slow biodegradation is a focus of controversy, and it is often abundant as a form of litter in the outdoor environment, particularly along shores and waterways especially in its low density cellular form.
As a thermoplastic polymer, polystyrene is in a solid (glassy) state at room temperature but flows if heated above about 100 °C, its glass transition temperature. It becomes rigid again when cooled. This temperature behavior is exploited for molding and extrusion, since it can be cast into molds with fine detail. Polystyrene can be transparent, white, or, upon dying, various colors.
Polystyrene was discovered in 1839 by Eduard Simon, an apothecary in Berlin. From storax, the resin of the
Rhyolite is an igneous, volcanic (extrusive) rock, of felsic (silica-rich) composition (typically > 69% SiO2 — see the TAS classification). It may have any texture from glassy to aphanitic to porphyritic. The mineral assemblage is usually quartz, alkali feldspar and plagioclase (in a ratio > 1:2 — see the QAPF diagram). Biotite and hornblende are common accessory minerals.
Rhyolite can be considered as the extrusive equivalent to the plutonic granite rock, and consequently, outcrops of rhyolite may bear a resemblance to granite. Due to their high content of silica and low iron and magnesium contents, rhyolite melts are highly polymerized and form highly viscous lavas. They can also occur as breccias or in volcanic plugs and dikes. Rhyolites that cool too quickly to grow crystals form a natural glass or vitrophyre, also called obsidian. Slower cooling forms microscopic crystals in the lava and results in textures such as flow foliations, spherulitic, nodular, and lithophysal structures. Some rhyolite is highly vesicular pumice. Many eruptions of rhyolite are highly explosive and the deposits may consist of fallout tephra/tuff or of ignimbrites.
In North American pre-historic times,
Sculpture is the branch of the visual arts that operates in three dimensions, and one of the plastic arts. Durable sculptural processes originally used carving (the removal of material) and modelling (the addition of material, as clay), in stone, metal, ceramics, wood and other materials but, since modernism, shifts in sculptural process led to an almost complete freedom of materials and process. A wide variety of materials may be worked by removal such as carving, assembled by welding or modelling, or molded, or cast.
Sculpture in stone survives far better than works of art in perishable materials, and often represents the majority of the surviving works (other than pottery) from ancient cultures, though conversely traditions of sculpture in wood may have vanished almost entirely. However, most ancient sculpture was brightly painted, and this has been lost.
Sculpture has been central in religious devotion in many cultures, and until recent centuries large sculptures, too expensive for private individuals to create, were usually an expression of religion or politics. Those cultures whose sculptures have survived in quantities include the cultures of the Ancient Mediterranean, India
Waxes are a class of chemical compounds that are plastic (malleable) near ambient temperatures. Characteristically, they melt above 45 °C (113 °F) to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, nonpolar solvents. All waxes are organic compounds, both synthetic and naturally occurring.
Waxes are organic compounds that characteristically consist of long alkyl chains. Natural waxes are typically esters of fatty acids and long chain alcohols. Synthetic waxes are long-chain hydrocarbons lacking functional groups.
Waxes are biosynthesized by many plants and animals. They typically consist of several components, including wax esters, wax acids, wax alcohols, and hydrocarbons. Wax esters are typically derived from a variety of carboxylic acids and a variety of fatty alcohols. The composition depends not only on species, but also on geographic location of the organism. Because they are mixtures, naturally produced waxes are softer and melt at lower temperatures than the pure components.
The most commonly known animal wax is beeswax, but other insects secrete waxes. A major component of beeswax is the ester myricyl palmitate substance which is used in
WEB is a computer programming system created by Donald E. Knuth as the first implementation of what he called "literate programming": the idea that one could create software as works of literature, by embedding source code inside descriptive text, rather than the reverse (as is common practice in most programming languages), in an order that is convenient for exposition to human readers, rather than in the order demanded by the compiler.
WEB consists of two primary programs: TANGLE, which produces compilable Pascal code from the source texts, and WEAVE, which produces nicely-formatted, printable documentation using TeX.
CWEB is a version of WEB for the C programming language, while noweb is a separate literate programming tool, which is inspired by WEB (as reflected in the name) and which is language agnostic.
The most significant programs written in WEB are TeX and Metafont. Modern TeX distributions use another program Web2C to convert WEB source to C.
Wove paper is a writing paper with a uniform surface, not ribbed or watermarked. The papermaking mould's wires run parallel to each other to produce laid paper, but they are woven together into a fine wire mesh for wove paper. The originator of this new papermaking technique was James Whatman (1702–59) from Kent, England.
For 500 years European paper makers could only produce what came to be called laid paper. In 1757 John Baskerville printed his famous edition of Virgil on a new kind of paper, called Wove (known in Europe as Vélin). This paper is now known to have been made by the elder James Whatman. Twenty-five years later (1780s) the manufacture of wove paper spread quickly to other paper mills in England, and was also being developed in France and America. All this took place over a decade before a machine to replace making paper by hand was conceived. With the establishment of the paper machine (1807), the manufacture of paper on a wove wire base never looked back. Today more than 99% of the world's paper is made in this way.
Whatman paper is a type of wove paper named after James Whatman. It is notable for its exceptional quality. Whatman paper is grained, strong and rigid,
Azulejo (Portuguese: [ɐzuˈleʒu], Spanish: [aθuˈlexo]) from the Arabic word Zellige زليج is a form of Portuguese painted, tin-glazed, ceramic tilework. It has become a typical aspect of Portuguese culture, having been produced without interruption for five centuries. There is also a tradition of their production in former Portuguese and Spanish colonies in Latin America.
In Portugal, azulejos are found on the interior and exterior of churches, palaces, ordinary houses and even train stations or subway stations. They constitute a major aspect of Portuguese architecture as they are applied on walls, floors and even ceilings. They were not only used as an ornamental art form, but also had a specific functional capacity like temperature control at homes. Many azulejos chronicle major historical and cultural aspects of Portuguese history.
The art was introduced to Portugal, by the Moors and the craft is still in use in the Arab world in two main traditions the "Egyptian Zalij" and the "Moroccan Zalij" the latter being the most famous. The word azulejo is derived from the Arabic word الزليج (al zulayj): zellige, meaning "polished stone". This origin explains the unmistakable Arab
Chalk ( /ˈtʃɔːk/) is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite plates (coccoliths) shed from micro-organisms called coccolithophores. It is common to find chert or flint nodules embedded in chalk. Chalk can also refer to other compounds including magnesium silicate and calcium sulfate.
Chalk has greater resistance to weathering and slumping than the clays with which it is usually associated, thus forming tall steep cliffs where chalk ridges meet the sea. Chalk hills, known as chalk downland, usually form where bands of chalk reach the surface at an angle, so forming a scarp slope. Because chalk is porous it can hold a large volume of ground water, providing a natural reservoir that releases water slowly through dry seasons.
The Chalk Group is a European stratigraphic unit deposited during the late Cretaceous Period. It forms the famous White Cliffs of Dover in Kent, England, as well as their counterparts of the Cap Blanc Nez on the other side of the Dover Strait. The Champagne region of France is
Gabbro ( /ˈɡæbroʊ/) refers to a large group of dark, coarse-grained, intrusive mafic igneous rocks chemically equivalent to basalt. The rocks are plutonic, formed when molten magma is trapped beneath the Earth's surface and cools into a crystalline mass.
The vast majority of the Earth's surface is underlain by gabbro within the oceanic crust, produced by basalt magmatism at mid-ocean ridges.
Gabbro is dense, greenish or dark-colored and contains pyroxene, plagioclase, amphibole, and olivine (olivine gabbro when olivine is present in a large amount).
The pyroxene is mostly clinopyroxene; small amounts of orthopyroxene may be present. If the amount of orthopyroxene is substantially greater than the amount of clinopyroxene, the rock is then a norite. Quartz gabbros are also known to occur and are probably derived from magma that was over-saturated with silica. Essexites represent gabbros whose parent magma was under-saturated with silica, resulting in the formation of the feldspathoid mineral nepheline. (Silica saturation of a rock can be evaluated by normative mineralogy). Gabbros contain minor amounts, typically a few percent, of iron-titanium oxides such as magnetite, ilmenite, and
Pewter is a malleable metal alloy, traditionally 85–99% tin, with the remainder consisting of copper, antimony, bismuth and (sometimes, and less commonly today) lead. Silver is also sometimes used. Copper and antimony act as hardeners while lead is common in the lower grades of pewter, which have a bluish tint. It has a low melting point, around 170–230 °C (338–446 °F), depending on the exact mixture of metals. The word pewter is probably a variation of the word spelter, a term for zinc alloys (originally a colloquial name for zinc).
Pewter was first used around the beginning of the Bronze Age in the Near East. The earliest piece of pewter found is from an Egyptian tomb from 1450 BC.
The constituents of pewter were first controlled in the 12th century by town guilds in France. By the 15th century, the Worshipful Company of Pewterers controlled pewter constituents in England. This company originally had two grades of pewter, but in the 16th century a third grade was added. The first type, known as "fine metal", was used for tableware. It consisted of tin with as much copper as it could absorb, which is about 1%. The second type, known as "trifling metal" or "trifle", was used for
Platinum ( /ˈplætɨnəm/ or /ˈplætənəm/) is a chemical element with the chemical symbol Pt and an atomic number of 78.
Its name is derived from the Spanish term platina, which is literally translated into "little silver". It is a dense, malleable, ductile, precious, gray-white transition metal.
Platinum has six naturally occurring isotopes. It is one of the rarest elements in the Earth's crust and has an average abundance of approximately 5 μg/kg. It is the least reactive metal. It occurs in some nickel and copper ores along with some native deposits, mostly in South Africa, which accounts for 80% of the world production.
As a member of the platinum group of elements, as well as of the group 10 of the periodic table of elements, platinum is generally non-reactive. It exhibits a remarkable resistance to corrosion, even at high temperatures, and as such is considered a noble metal. As a result, platinum is often found chemically uncombined as native platinum. Because it occurs naturally in the alluvial sands of various rivers, it was first used by pre-Columbian South American natives to produce artifacts. It was referenced in European writings as early as 16th century, but it was not
Quillwork is a form of textile embellishment traditionally practiced by Native Americans that employs the quills of porcupines as a decorative element.
Porcupine quillwork is an art form completely unique to North America. Before the introduction of glass beads, quillwork was a major decorative element used by the peoples who resided in the porcupine's natural habitat. The use of quills in designs spans from Maine to Alaska. The earliest known quillwork was found in Alberta, Canada and dates back to the 6th century CE.
Cheyenne oral history, as told by Picking Bones Woman to George Bird Grinnell, says quilling came to their tribe from a man who married a woman, who hid her true identity as a buffalo. His son was also a buffalo. The man visited his wife and son in their buffalo home, and, while among the buffalo, the man learned the art of quilling, which he shared with the women of his tribe.
Joining the Cheyenne Quilling Society was a prestigious honor for Cheyenne women. Upon entering the Society, women would work first on quilling moccasins, then cradleboards, rosettes for men's shirts and tipis, and ultimately, hide robes and backrests.
Porcupine quills often adorned rawhide
Silver ( /ˈsɪlvər/ SIL-vər) is a metallic chemical element with the chemical symbol Ag (Greek: άργυρος , Latin: argentum, both from the Indo-European root *arg- for "grey" or "shining") and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal. The metal occurs naturally in its pure, free form (native silver), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining.
Silver has long been valued as a precious metal, and it is used as an investment, to make ornaments, jewelry, high-value tableware, utensils (hence the term silverware), and currency coins. Today, silver metal is also used in electrical contacts and conductors, in mirrors and in catalysis of chemical reactions. Its compounds are used in photographic film, and dilute silver nitrate solutions and other silver compounds are used as disinfectants and microbiocides (Oligodynamic effect). While many medical antimicrobial uses of silver have been supplanted by antibiotics, further research
Tilia americana is a species of Tilia native to eastern North America, from southeast Manitoba east to New Brunswick, southwest to northeast Texas, and southeast to South Carolina, and west along the Niobrara River to Cherry County, Nebraska. Common names include American Linden and Basswood (also applied to other species of Tilia in the timber trade).
Tilia americana is a medium-sized to large deciduous tree reaching a height of 60 to 120 ft (exceptionally 129 ft) with a trunk diameter of 3–4 ft at maturity. The crown is domed, the branches spreading, often pendulous. The bark is gray to light brown, with narrow, well defined fissures. The roots are large, deep, and spreading. The twigs are smooth, reddish-green, becoming light gray in their second year, finally dark brown or brownish gray, marked with dark wart-like excrescences. The winter buds are stout, ovate-acute, smooth, deep red, with two bud scales visible. The leaves are simple, alternately arranged, ovate to cordate, inequalateral at the base (the side nearest the branch the largest), 10–15 cm (can grow up to 25 cm) long and broad, with a long, slender petiole, a coarsely serrated margin and an acuminate apex. They open
Willows, sallows, and osiers form the genus Salix, around 400 species of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere. Most species are known as willow, but some narrow-leaved shrub species are called osier, and some broader-leaved species are referred to as sallow (from Old English sealh, related to the Latin word salix, willow). Some willows (particularly arctic and alpine species) are low-growing or creeping shrubs; for example, the dwarf willow (Salix herbacea) rarely exceeds 6 cm (2 in) in height, though it spreads widely across the ground.
Willows are very cross-fertile, and numerous hybrids occur, both naturally and in cultivation. A well-known ornamental example is the weeping willow (Salix × sepulcralis), which is a hybrid of Peking willow (Salix babylonica) from China and white willow (Salix alba) from Europe.
Willows all have abundant watery bark sap, which is heavily charged with salicylic acid, soft usually pliant tough wood, slender branches and large fibrous often stoloniferous roots. The roots are remarkable for their toughness, size, and tenacity to life, and roots readily grow from aerial parts
Woodcut—occasionally known as xylography—is a relief printing artistic technique in printmaking in which an image is carved into the surface of a block of wood, with the printing parts remaining level with the surface while the non-printing parts are removed, typically with gouges. The areas to show 'white' are cut away with a knife or chisel, leaving the characters or image to show in 'black' at the original surface level. The block is cut along the grain of the wood (unlike wood engraving where the block is cut in the end-grain). The surface is covered with ink by rolling over the surface with an ink-covered roller (brayer), leaving ink upon the flat surface but not in the non-printing areas.
Multiple colors can be printed by keying the paper to a frame around the woodblocks (where a different block is used for each color). The art of carving the woodcut can be called "xylography", but this is rarely used in English for images alone, although that and "xylographic" are used in connection with blockbooks, which are small books containing text and images in the same block. Single-leaf woodcut is a term for a woodcut presented as a single image or print, as opposed to a book
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera.
Limestone makes up about 10% of the total volume of all sedimentary rocks. The solubility of limestone in water and weak acid solutions leads to karst landscapes, in which water erodes the limestone over thousands to millions of years. Most cave systems are through limestone bedrock.
Limestone has numerous uses: as a building material, as aggregate for the base of roads, as white pigment or filler in products such as toothpaste or paints, and as a chemical feedstock.
The first who distinguished limestone from dolomite was Belsazar Hacquet in 1778.
Like most other sedimentary rocks, most limestone is composed of grains. Most grains in limestone are skeletal fragments of marine organisms such as coral or foraminifera. Other carbonate grains comprising limestones are ooids, peloids, intraclasts, and extraclasts. These organisms secrete shells made of aragonite or calcite, and leave these shells behind after the organisms
A panel painting is a painting made on a flat panel made of wood, either a single piece, or a number of pieces joined together. Until canvas became the more popular support medium in the 16th century, it was the normal form of support for a painting not on a wall (fresco) or vellum, which was used for miniatures in illuminated manuscripts and paintings for the framing.
Panel painting is very old; it was a very prestigious medium in Greece and Rome, but only very few examples of ancient panel paintings have survived. A series of 6th century BC painted tablets from Pitsa (Greece) represent the oldest surviving Greek panel paintings. Most classical Greek paintings that were famous in their day seem to have been of a size comparable to smaller modern works - perhaps up to a half-length portrait size. However for a generation in the second quarter of the fifth-century BC there was a movement, called the "new painting" and led by Polygnotus, for very large painted friezes, apparently painted on wood, decorating the interiors of public buildings with very large and complicated subjects containing numerous figures at at least half life-size, and including battle scenes. We can only attempt
Red ochre and yellow ochre (pronounced /ˈoʊkər/, from the Greek ὄχρος, yellow) are pigments made from naturally tinted clay. It has been used worldwide since prehistoric times. Chemically, it is hydrated iron (III) oxide.
Ochres are non-toxic, and can be used to make an oil paint that dries quickly and covers surfaces thoroughly. Many people believe that the best ochre comes from the area of Roussillon, France.
To manufacture ground ochre, ochre clay is first mined from the ground. It is then washed in order to separate sand from ochre, which can be done by hand. The remaining ochre is then dried in the sun and sometimes burned to enhance the natural colour.
Ochre was one of the first pigments to be used by human beings. Pieces of haematite, worn down as though they had been used as crayons, have been found at 300,000 year old Homo heidelbergensis sites in France and Czechoslovakia. Neanderthal burial sites sometimes include ochre as a grave good. The oldest evidence of mining activity, at the "Lion Cave" in Swaziland, is a 43,000 year old ochre mine. In Germanic rune lore, red ochre was often used in place of blood to redden, or tint, the runes and thereby instilling the spirit of
Vellum is derived from the Latin word “vitulinum” meaning "made from calf", leading to Old French “Vélin” ("calfskin"). It is mammal skin prepared for writing or printing on, to produce single pages, scrolls, codices or books. It is a near-synonym of the word parchment, but "vellum" tends to be the term used for finer-quality parchment.
Vellum is generally smooth and durable, although there are great variations depending on preparation, the quality of the skin and the type of animal used. The manufacture involves the cleaning, bleaching, stretching on a frame (a “herse”), and scraping of the skin with a hemispherical knife (a “lunarium” or “lunellum”). To create tension, scraping is alternated with wetting and drying. A final finish may be achieved by abrading the surface with pumice, and treating with a preparation of lime or chalk to make it accept writing or printing ink. Modern "paper vellum" (vegetable vellum) is used for a variety of purposes, especially for plans, technical drawings, and blueprints.
Vellum is a translucent material produced from the skin, often split, of a young animal. The skin is washed with water and lime (Calcium hydroxide), but not together. It is then
Casein paint, derived from milk casein, is a fast-drying, water-soluble medium used by artists. It generally has a glue-like consistency, but can be thinned with water to the degree that fits a particular artist's style and desired result. It can be used on canvas panels, illustration boards, paper, wood and masonite. Because the dried paint film is inflexible and brittle, it is not appropriate to be applied in heavy impastos on flexible supports such as canvas. Casein paint is reworkable and can be used for underpainting. It generally dries to a matte finish.
Casein paint has been used since ancient Egyptian times as a form of tempera paint, and is still used today. One of the qualities that artists value casein paint for is that, unlike gouache, it dries to an even consistency making it ideal for murals. Also, visually it can resemble oil painting more than most other water based paints, and works well as an underpainting.
A quick way to make casein painting medium is to take some skim milk cottage cheese and first wash off any of the milky fluids. The lumps of casein left behind are then dissolved by adding, in a pot, water and some ammonia. The ammonia should be preferably in
Gesso (Italian:ˈdʒɛsːo "chalk," from the Latin gypsum, from the Greek γύψος) is a white paint mixture consisting of a binder mixed with chalk, gypsum, pigment, or any combination of these. It is used in artwork as a preparation for any number of substrates such as wood panels, canvas and sculpture as a base for paint and other materials that are applied over it.
"Gesso", also known "glue gesso" or "Italian gesso" is a traditional mix of an animal glue binder (usually rabbit-skin glue), chalk, and white pigment, used to coat rigid surfaces such as wooden painting panels as an absorbent primer coat substrate for painting. The colour of gesso was usually white or off-white. Its absorbency makes it work with all painting media, including water-based media, different types of tempera, and oil paint. It is also used as a base on three-dimensional surfaces for the application of paint or gold leaf. Mixing and applying it is an art form in itself since it is usually applied in 10 or more extremely thin layers. It is a permanent and brilliant white substrate used on wood, masonite and other surfaces. The standard hide glue mixture is rather brittle and susceptible to cracking, thus making
Jute is a long, soft, shiny vegetable fibre that can be spun into coarse, strong threads. It is produced from plants in the genus Corchorus, which has been classified in the family Tiliaceae, or more recently in Malvaceae. However, it has been reclassified within the family Sparrmanniaceae.
Jute is one of the most affordable natural fibres and is second only to cotton in amount produced and variety of uses of vegetable fibres. Jute fibres are composed primarily of the plant materials cellulose (major component of plant fibre) and lignin (major components of wood fibre). It is thus a ligno-cellulosic fibre that is partially a textile fibre and partially wood. It falls into the bast fibre category (fibre collected from bast or skin of the plant) along with kenaf, industrial hemp, flax (linen), ramie, etc. The industrial term for jute fibre is raw jute. The fibres are off-white to brown, and 1–4 metres (3–12 feet) long.
Jute needs a plain alluvial soil and standing water. The suitable climate for growing jute (warm and wet climate) is offered by the monsoon climate during the monsoon season. Temperatures from 20˚C to 40˚C and relative humidity of 70%–80% are favourable for successful
Oil paint is a type of slow-drying paint that consists of particles of pigment suspended in a drying oil, commonly linseed oil. The viscosity of the paint may be modified by the addition of a solvent such as turpentine or white spirit, and varnish may be added to increase the glossiness of the dried oil paint film. Oil paints have been used in Europe since the 12th century for simple decoration, but were not widely adopted as an artistic medium until the early 15th century. Common modern applications of oil paint are in finishing and protection of wood in buildings and exposed metal structures such as ships and bridges. Its hard-wearing properties and luminous colors make it desirable for both interior and exterior use on wood and metal. Due to its slow-drying properties, it has recently been used in paint-on-glass animation. Thickness of coat has considerable bearing on time required for drying: thin coats of oil paint dry relatively quickly.
The technical history of the introduction and development of oil paint, and the date of introduction of various additives (driers, thinners) is still - despite intense research since the mid 18th century - not well understood. The literature
Polyvinyl chloride, commonly abbreviated PVC, is the third-most widely produced plastic, after polyethylene and polypropylene. PVC is used in construction because it is cheaper and stronger than more traditional alternatives such as copper or ductile iron. It can be made softer and more flexible by the addition of plasticizers, the most widely used being phthalates. In this form, it is used in clothing and upholstery, electrical cable insulation, inflatable products and many applications in which it replaces rubber.
Pure polyvinyl chloride without any plasticizer is a white, brittle solid. It is insoluble in alcohol, but slightly soluble in tetrahydrofuran.
PVC was accidentally discovered at least twice in the 19th century, first in 1835 by French chemist Henri Victor Regnault and then in 1872 by German chemist Eugen Baumann. On both occasions the polymer appeared as a white solid inside flasks of vinyl chloride that had been left exposed to sunlight. In the early 20th century the Russian chemist Ivan Ostromislensky and Fritz Klatte of the German chemical company Griesheim-Elektron both attempted to use PVC in commercial products, but difficulties in processing the rigid, sometimes
A stencil is a thin sheet of material, such as paper, plastic, or metal, with letters or a design cut from it, used to produce the letters or design on an underlying surface by applying pigment through the cut-out holes in the material. The key advantage of a stencil is that it can be reused to repeatedly and rapidly produce the same letters or design. The design produced with a stencil is also called a stencil. The context in which stencil is used makes clear which meaning is intended. Although aerosol or painting stencils can be made for one-time use, typically they are made to be reusable. To be reusable, they must remain intact after a design is produced and the stencil is removed from the work surface. With some designs, this is done by connecting stencil islands (sections of material that are inside cut-out "holes" in the stencil) to other parts of the stencil with bridges (narrow sections of material that are not cut out).
Stencil technique in visual art is also referred to as pochoir. A related technique (which has found applicability in some surrealist compositions) is aerography, in which spray-painting is done around a three-dimensional object to create a negative of the
Block printing is a special form of printing first developed in China. The earliest known example with an actual date is a copy of the Diamond Sutra from 868 A.D. (currently in the British Museum), though the practice of block printing is probably about two thousand years old.
The first step in block printing is the production of the original document. This is laid on a large, smooth wooden block and fixed into place, reversed. Next, craftsmen of various skill levels, ranging from master carver for the fine work to less talented artisan for cheaper blocks or less important sections, carve the original painted, drawn or written image into the block of wood. The block can now be covered with ink and used in a press to create duplicates of the original.
In some ways block printing is superior to cast type or moveable type -- for a language such as Chinese which has a very broad character set, block prints are much cheaper to produce for the initial run.The process also allows greater artistic freedom, such as the easy inclusion of pictures and diagrams.However, printing blocks are not very durable, and deteriorate very rapidly with use, requiring constant replacement which limits
C-print or Kodak C-print is a common brand name for a "color coupler print" or "digital color coupler print" and refers specifically to a photographic print made from a color negative using the same extremely light-sensitive silver salts as found in silver gelatin prints, except the silver salts 'couple' with colored dyes to form high-resolution color image rather than black and white ones. One of the finest exponents of the c-print is Candida Hￃﾶfer whose photograph entitled Musￃﾩe du Louvre Paris XIII showing one of the classical galleries in the Louvre was on display at the Royal Academy 2007 Summer Exhibition, Burlington House, Piccadilly, London W1.
Another fine example is Jim Dow. Considered one of the finest practitioners on the craft of c-printing. Using multiple color images taken with an 8 x 10 camera, Jim Dow creates highly detailed panoramas offering an unusual view of the ballparks as seen from a fan's point of view. Developed while photographing soccer stadiums in England and influenced by pioneering photographer Walker Evans, Dow's vision results in "astonishing, disturbing, and wholly unexpected" images of the empty spaces. "I have an old-fashioned, romantic
Encaustic painting, also known as hot wax painting, involves using heated beeswax to which colored pigments are added. The liquid/paste is then applied to a surface—usually prepared wood, though canvas and other materials are often used. The simplest encaustic mixture can be made from adding pigments to beeswax, but there are several other recipes that can be used — some containing other types of waxes, damar resin, linseed oil, or other ingredients. Pure, powdered pigments can be used, though some mixtures use oil paints or other forms of pigment.
Metal tools and special brushes can be used to shape the paint before it cools, or heated metal tools can be used to manipulate the wax once it has cooled onto the surface. Today, tools such as heat lamps, heat guns, and other methods of applying heat allow artists to extend the amount of time they have to work with the material. Because wax is used as the pigment binder, encaustics can be sculpted as well as painted. Other materials can be encased or collaged into the surface, or layered, using the encaustic medium to adhere it to the surface.
This technique was notably used in the Fayum mummy portraits from Egypt around 100-300 AD, in
Gold ( /ˈɡoʊld/) is a dense, soft, shiny, malleable and ductile metal. It is a chemical element with the symbol Au and atomic number 79.
Gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a transition metal and a group 11 element. It is one of the least reactive chemical elements solid under standard conditions. The metal therefore occurs often in free elemental (native) form, as nuggets or grains in rocks, in veins and in alluvial deposits. Less commonly, it occurs in minerals as gold compounds, usually with tellurium.
Gold resists attacks by individual acids, but it can be dissolved by the aqua regia (nitro-hydrochloric acid), so named because it dissolves gold. Gold also dissolves in alkaline solutions of cyanide, which have been used in mining. Gold dissolves in mercury, forming amalgam alloys. Gold is insoluble in nitric acid, which dissolves silver and base metals, a property that has long been used to confirm the presence of gold in items, giving rise to the term the acid test.
Gold has been a valuable and highly sought-after precious metal for coinage, jewelry, and other
The mineral graphite /ˈɡræfaɪt/ is an allotrope of carbon. It was named by Abraham Gottlob Werner in 1789 from the Ancient Greek γράφω (graphō), "to draw/write", for its use in pencils, where it is commonly called lead (not to be confused with the metallic element lead). Unlike diamond (another carbon allotrope), graphite is an electrical conductor, a semimetal. It is, consequently, useful in such applications as arc lamp electrodes. Graphite is the most stable form of carbon under standard conditions. Therefore, it is used in thermochemistry as the standard state for defining the heat of formation of carbon compounds. Graphite may be considered the highest grade of coal, just above anthracite and alternatively called meta-anthracite, although it is not normally used as fuel because it is difficult to ignite.
There are three principal types of natural graphite, each occurring in different types of ore deposit:
Highly ordered pyrolytic graphite or highly oriented pyrolytic graphite (HOPG) refers to graphite with an angular spread between the graphite sheets of less than 1°. This highest-quality synthetic form is used in scientific research, in particular, as a standard for scanner
Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications including packaging and labeling, textiles (e.g., ropes, thermal underwear and carpets), stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes. An addition polymer made from the monomer propylene, it is rugged and unusually resistant to many chemical solvents, bases and acids.
In 2008, the global market for polypropylene had a volume of 45.1 million tonnes, which led to a turnover of about $65 billion (~ €47.4 billion).
Most commercial polypropylene is isotactic and has an intermediate level of crystallinity between that of low-density polyethylene (LDPE) and high-density polyethylene (HDPE). Polypropylene is normally tough and flexible, especially when copolymerized with ethylene. This allows polypropylene to be used as an engineering plastic, competing with materials such as ABS. Polypropylene is reasonably economical, and can be made translucent when uncolored but is not as readily made transparent as polystyrene, acrylic, or certain other plastics. It is often opaque or
Artworks:Greek Bust from the British Museum, Knight Collection
The salt print was the dominant paper-based photographic process for producing positive prints during the period from 1839 through approximately 1860.
The salted paper technique was created by British photographer William Henry Fox Talbot. He called his negative process calotype printing, while the salt print process was used for making positive prints from the Calotype negatives. They both employ a technique of coating sheets of paper with silver salts, but the Calotype process differs slightly in chemicals used in the sensitization procedure, and uses an extra 'accelerator' step, immediately prior to exposure of the sensitized paper.
Taylor, Roger. Impressed by Light: British Photographs from Paper Negatives, 1840-1860 (NY, Metropolitan Museum of Art, 2007)
Synthetic fabrics are textiles made from synthetic fibers. They are used primarily to make clothing. A synthetic fabric is plastic fabric. Some of the examples of synthetic clothings were usually made of polyester, acrylic, and nylon. A synthetic fibre, when magnified, looks like plastic spun together.Man-made fabrics, also known as synthetic fabrics include fabrics such as rayon, acetate, nylon, acrylic, polyester, olefin, spandex, lastex and kevlar. These fabrics have many different uses and qualities, some which can not be achieved with natural fibers. With synthetic fibers one can create waterproof fabrics and fabrics with an excellent amount of stretch used for swimwear and lingerie.
The fabric is made from chemically produced fibers. The chemicals used to make the fibers are sodium hydroxide and and carbon di-sulphide which are derived from coal, oil, or natural gas. The chemicals are in liquid form and are forced through tiny holes called spinnerets. As the liquid comes out of the spinnerets and into the air, it cools and forms into tiny threads. Dyes are added to these threads before they are woven together to make the fabric.
Depending on the fabric, other chemicals are
Teeth of humans are small, calcified, hard, whitish structures found in the mouth. They function in mechanically breaking down items of food by cutting and crushing them in preparation for swallowing and digestion. The roots of teeth are embedded in the maxilla (upper jaw) or the mandible (lower jaw) and are covered by gums. Teeth are made of multiple tissues of varying density and hardness.
Teeth are among the most distinctive (and long-lasting) features of mammal species. Humans, like other mammals, are diphyodont, meaning that they develop two sets of teeth. The first set (also called the "baby", "milk", "primary", and "deciduous" set) normally starts to appear at about six months of age, although some babies are born with one or more visible teeth, known as neonatal teeth. Normal tooth eruption at about six months is known as teething and can be painful.
Dental trauma refers to trauma to the face, mouth, and especially the teeth lips and periodontium. The study of dental trauma is called dental traumatology.
Dental anatomy is a field of anatomy dedicated to the study of tooth structure. The development, appearance, and classification of teeth fall within its field of study,
Adobe ( /əˈdoʊbi/, UK /əˈdoʊb/; Arabic: الطوب) is a natural building material made from sand, clay, water, and some kind of fibrous or organic material (sticks, straw, and/or manure), which the builders shape into bricks (using frames) and dry in the sun. Adobe buildings are similar to cob and mudbrick buildings. Adobe structures are extremely durable, and account for some of the oldest existing buildings in the world. In hot climates, compared with wooden buildings, adobe buildings offer significant advantages due to their greater thermal mass, but they are known to be particularly susceptible to earthquake damage.
Buildings made of sun-dried earth are common in West Asia, North Africa, West Africa, South America, southwestern North America, Spain (usually in the Mudéjar style), Eastern Europe and East Anglia, particularly Norfolk, known as 'clay lump. Adobe had been in use by indigenous peoples of the Americas in the Southwestern United States, Mesoamerica, and the Andean region of South America for several thousand years, although often substantial amounts of stone are used in the walls of Pueblo buildings. (Also, the Pueblo people built their adobe structures with handfuls or
Egg tempera is an art medium that uses real egg yolk, egg white, or both in its formulation. There are synthetic forms of tempera, however this topic is about the art medium that uses a binding agent (binder) made from real eggs.
Magnesite is magnesium carbonate, MgCO3. Iron (as Fe) substitutes for magnesium (Mg) with a complete solution series with siderite, FeCO3. Calcium, manganese, cobalt, and nickel may also occur in small amounts. Dolomite, (Mg,Ca)CO3, is almost indistinguishable from magnesite.
Magnesite occurs as veins in and an alteration product of ultramafic rocks, serpentinite and other magnesium rich rock types in both contact and regional metamorphic terranes. These magnesites often are cryptocrystalline and contain silica as opal or chert.
Magnesite is also present within the regolith above ultramafic rocks as a secondary carbonate within soil and subsoil, where it is deposited as a consequence of dissolution of magnesium-bearing minerals by carbon dioxide within groundwaters.
Magnesite can be formed via talc carbonate metasomatism of peridotite and other ultrabasic rocks. Magnesite is formed via carbonation of olivine in the presence of water and carbon dioxide, and is favored at moderate temperatures and pressures typical of greenschist facies;
Magnesite can also be formed via the carbonation of magnesian serpentine (lizardite) via the following reaction:
Serpentine + carbon dioxide → Talc
Tortoiseshell or tortoise shell is a material produced mainly from the shell of the hawksbill turtle, an endangered species. It was widely used until the 1970s in the manufacture of items such as combs, sunglasses, guitar picks and knitting needles. In 1973, the trade of tortoiseshell worldwide was banned under CITES (the Convention on International Trade in Endangered Species).
Tortoiseshell was attractive to manufacturers and consumers because of its beautiful appearance and its durability, and its organic warmth against the skin. It was used in guitar picks because it can be easily shaped, has excellent bending properties, and is very durable – tortoiseshell picks could sometimes be used for years. Piqué-work, jewelry made from tortoiseshell inlaid with precious metals in patterns or pictures, was made during the Victorian Era and was highly prized.
Since the 1973 ban on tortoiseshell commerce, replacements have been developed. The synthetic Delrin has been used especially for guitar picks.
Installation art describes an artistic genre of three-dimensional works that are often site-specific and designed to transform the perception of a space. Generally, the term is applied to interior spaces, whereas exterior interventions are often called Land art; however, the boundaries between these terms overlap.
Installation art can be either temporary or permanent. Installation artworks have been constructed in exhibition spaces such as museums and galleries, as well as public and private spaces. The genre incorporates a broad range of everyday and natural materials, which are often chosen for their "evocative" qualities, as well as new media such as video, sound, performance, immersive virtual reality and the internet. Many installations are site-specific in that they are designed to exist only in the space for which they were created. A number of institutions focusing on Installation art were created from the 1980s onwards, suggesting the need for Installation to be seen as a separate discipline. These included the Mattress Factory, Pittsburgh, the Museum of Installation in London, and the Fairy Doors of Ann Arbor, MI, among others.
Installation art came to prominence in the
Poly(methyl methacrylate) (PMMA) is a transparent thermoplastic, often used as a lightweight or shatter-resistant alternative to glass. It is sometimes called acrylic glass. Chemically, it is the synthetic polymer of methyl methacrylate. The material was developed in 1928 in various laboratories, and was first brought to market in 1933 by the Rohm and Haas Company, under the trademark Plexiglas. It has since been sold under many different names, including Lucite and Perspex.
The often-seen spelling poly(methyl 2-methylpropanoate) with -an- is an error for poly(methyl 2-methylpropenoate), based on propenoic acid.
PMMA is an economical alternative to polycarbonate (PC) when extreme strength is not necessary. Additionally, PMMA does not contain the potentially harmful bisphenol-A subunits found in polycarbonate. It is often preferred because of its moderate properties, easy handling and processing, and low cost. The non-modified PMMA behaves in a brittle manner when loaded, especially under an impact force, and is more prone to scratching than conventional inorganic glass. However, the modified PMMA achieves very high scratch and impact resistance.
The first acrylic acid was created
An album cover is the front of the packaging of a commercially released audio recording product, or album. The term can refer to either the printed cardboard covers typically used to package sets of 10 in (25 cm) and 12 in (30 cm) 78 rpm records, single and sets of 12" LPs, sets of 45 rpm records (either in several connected sleeves or a box), or the front-facing panel of a CD package, and, increasingly, the primary image accompanying a digital download of the album, or of its individual tracks.
In addition, in the case of all types of records, it also serves as part of the protective sleeve.
Around 1910, 78 rpm records replaced phonograph cylinder as the medium for recorded sound. The 78 rpm records were issued in both 10" and 12" diameter sizes and were usually sold separately, in brown paper or cardboard sleeves that were sometimes plain and sometimes printed to show the producer or the retailer's name. These were invariably made out of acid paper, limiting conservability. Generally the sleeves had a circular cutout allowing the record label to be seen. Records could be laid on a shelf horizontally or stood upright on an edge, but because of their fragility, many broke in
Monotyping is a type of printmaking made by drawing or painting on a smooth, non-absorbent surface. The surface, or matrix, was historically a copper etching plate, but in contemporary work it can vary from zinc or glass to acrylic glass. The image is then transferred onto a sheet of paper by pressing the two together, usually using a printing-press. Monotypes can also be created by inking an entire surface and then, using brushes or rags, removing ink to create a subtractive image, e.g. creating lights from a field of opaque colour. The inks used may be oil based or water based. With oil based inks, the paper may be dry, in which case the image has more contrast, or the paper may be damp, in which case the image has a 10 percent greater range of tones.
Monotyping produces a unique print, or monotype; most of the ink is removed during the initial pressing. Although subsequent reprintings are sometimes possible, they differ greatly from the first print and are generally considered inferior. These prints from the original plate are called "ghost prints." Prints made by pressing the prints onto another surface, effectively making the print into a plate, is called a "cognate".
Aluminium ( /ˌæljuːˈmɪniəm/ AL-ew-MIN-ee-əm) or aluminum (American English; /əˈluːmɪnəm/ ə-LOO-mi-nəm) is a chemical element in the boron group with symbol Al and atomic number 13. It is silvery white, and it is not soluble in water under normal circumstances.
Aluminium is the third most abundant element (after oxygen and silicon), and the most abundant metal, in the Earth's crust. It makes up about 8% by weight of the Earth's solid surface. Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is found combined in over 270 different minerals. The chief ore of aluminium is bauxite.
Aluminium is remarkable for the metal's low density and for its ability to resist corrosion due to the phenomenon of passivation. Structural components made from aluminium and its alloys are vital to the aerospace industry and are important in other areas of transportation and structural materials. The most useful compounds of aluminium, at least on a weight basis, are the oxides and sulfates.
Despite its prevalence in the environment, aluminium salts are not known to be used by any form of life. In keeping with its
An art car is a vehicle that has had its appearance modified as an act of personal artistic expression. Art cars are often driven and owned by their creators, who are sometimes referred to as "Cartists".
Most car artists are ordinary people with no artistic training. Artists are largely self-taught and self funded, though some mainstream trained artists have also worked in the art car medium. Most others agree that creating and driving an art car daily is its own reward. Artists like Roy Lichtenstein, Andy Warhol and others have designed BMW Art Cars and their work has been reflected in racing cars like the BMW V12 LMR.
There is some disagreement as to what precisely led to the growth of the art car world. It can be seen as a twining together of several influences - the hippie-themed VWs of the late 1960s, the lowrider, as well as a Merry Pranksters' creation, the decorated schoolbus known as Further.
During the late 1960s, singer Janis Joplin had a psychedelically-painted Porsche 356 and John Lennon, a paisley Rolls Royce. Partly in imitation, the late 1960s/early 1970s counterculture featured many painted VW Buses and customized vehicles (e.g. a customized 1977 Cadillac
Boards are a basic component of many buildings. They are fashioned by cutting wood in a Wood Plane or Carpentry Bench. They require the Carpentry skill to produce.
With the Wood Treatment tech, ordinary boards can be treated in a Wood Treatment Tank to imbue them with specific characteristics.
Cardboard is a generic term for a heavy-duty paper of various strengths, ranging from a simple arrangement of a single thick sheet of paper to complex configurations featuring multiple corrugated and uncorrugated layers.
Despite widespread use in general English, the term is deprecated in business and industry. Material producers, container manufacturers, packaging engineers, and standards organizations, try to use more specific terminology. There is still no complete and uniform usage. Often the term "cardboard" is avoided because it does not define any particular material.
The term has been used since at least as early as 1683 when, with a publication of that year stating that "The scabbards mentioned in printers' grammars of the last century were of cardboard or millboard". The Kellogg brothers first used paperboard cartons to hold their flaked corn cereal, and later, when they began marketing it to the general public, a heat-sealed bag of Wax paper was wrapped around the outside of the box and printed with their brand name. This marked the origin of the cereal box, though in modern times, the sealed bag is plastic and is kept inside the box rather than outside. Another early
In mineralogy, diamond (from the ancient Greek αδάμας – adámas "unbreakable") is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions. Diamond is renowned as a material with superlative physical qualities, most of which originate from the strong covalent bonding between its atoms. In particular, diamond has the highest hardness and thermal conductivity of any bulk material. Those properties determine the major industrial application of diamond in cutting and polishing tools and the scientific applications in diamond knives and diamond anvil cells.
Diamond has remarkable optical characteristics. Because of its extremely rigid lattice, it can be contaminated by very few types of impurities, such as boron and nitrogen. Combined with wide transparency, this results in the clear, colorless appearance of most natural diamonds. Small amounts of defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (lattice defects),
A mirror is an object that reflects light or sound in a way that preserves much of its original quality subsequent to its contact with the mirror. Some mirrors also filter out some wavelengths, while preserving other wavelengths in the reflection. This is different from other light-reflecting objects that do not preserve much of the original wave signal other than color and diffuse reflected light. The most familiar type of mirror is the plane mirror, which has a flat surface. Curved mirrors are also used, to produce magnified or diminished images or focus light or simply distort the reflected image.
Mirrors are commonly used for personal grooming or admiring oneself (in which case the archaic term looking-glass is sometimes still used), decoration, and architecture. Mirrors are also used in scientific apparatus such as telescopes and lasers, cameras, and industrial machinery. Most mirrors are designed for visible light; however, mirrors designed for other types of waves or other wavelengths of electromagnetic radiation are also used, especially in non-optical instruments.
The first mirrors used by people were most likely pools of dark, still water, or water collected in a
Parian marble is a fine-grained semitranslucent pure-white and entirely flawless marble quarried during the classical era on the Greek island of Paros in the Aegean Sea.
It was highly prized by ancient Greeks for making sculptures. Some of the greatest masterpieces of ancient Greek sculpture were carved from Parian marble, including the Medici Venus and the Winged Victory of Samothrace.
The original quarries, which were used from the 6th century BC onwards, can still be seen on the north side of the island on the slopes of its central peak. The Parian's main rival in antiquity was Pentelic marble, which is also flawless white, albeit with a uniform, faint yellow tint that makes it shine with a golden hue under sunlight. Italian Carrara marble is also flawless white with a uniform faint grey tint.
The Parian Ware is an artificial substitute for marble made from unglazed porcelain, developed in 1842 in England.
Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery and ropemaking. Thread is a type of yarn intended for sewing by hand or machine. Modern manufactured sewing threads may be finished with wax or other lubricants to withstand the stresses involved in sewing. Embroidery threads are yarns specifically designed for hand or machine embroidery.
The word yarn comes from Middle English, from Old English gearn; akin to Old High German garn yarn, Greek chordē string, Latin hernia rupture, Sanskrit hira band.
Yarn can be made from any number of natural or synthetic fibers.
The most common plant fiber is cotton, which is typically spun into fine yarn for mechanical weaving or knitting into cloth. The most commonly used animal fiber is wool harvested from sheep. For hand knitting and hobby knitting, thick wool yarns are frequently used.
Other animal fibers used include alpaca, angora, mohair, llama, cashmere, and silk. More rarely, yarn may be spun from camel, yak, possum, qiviut, cat, dog, wolf, rabbit, or buffalo hair, and even turkey or ostrich feathers. Natural fibers such as these have
Artworks:Velveteen Rabbit Attempts to Become Real Through the Magic of Prosthesis
Velvet is a type of woven tufted fabric in which the cut threads are evenly distributed, with a short dense pile, giving it a distinctive feel.
The word 'velvety' is used as an adjective to mean "smooth like velvet". Velvet can be either synthetic or natural.
Velvet is woven on a special loom that weaves two thicknesses of velvet at the same time. The two pieces are then cut apart to create the pile effect, and the two lengths of fabric are wound on separate take-up rolls. Velvet was expensive to make before industrial power looms became available. Velvet is difficult to clean because of its pile, but modern dry cleaning methods make cleaning more feasible. Velvet pile is created by warp or vertical yarns and velveteen pile is created by weft or fill yarns.
Velvet can be made from many different kinds of fibres, traditionally silk. Velvet made entirely from silk has market prices of several hundred US dollars per yard. Cotton can also be used, though this often results in a slightly less luxurious fabric. Velvet can also be made from fibers such as linen, mohair, and wool. A cloth made by the Kuba people of the Democratic Republic of Congo from raffia is often referred to as "Kuba
Wood engraving is a technique in printmaking where the "matrix" worked by the artist is a block of wood. It is a variety of woodcut and so a relief printing technique, where ink is applied to the face of the block and printed by using relatively low pressure. A normal engraving, like an etching, has a metal plate as a matrix and is printed by the intaglio method. In wood engraving the technique for working the block is different from woodcut, using an engraver's burin to create very thin delicate lines, and often having large dark areas in the composition, though by no means always. Wood engraving traditionally utilizes the end grain of wood as a medium for engraving, while in the older technique of woodcut the softer side grain is used.
The technique of wood engraving developed at the end of the 18th century and the beginning of the 19th century, with the works of Thomas Bewick. Bewick generally made his engraving in harder woods than are now normally used, and would engrave the end of a block instead of the side. Finding a knife not suitable for working against the grain in harder woods, Bewick used the engraving tool the burin, which has a V-shaped cutting tip. Engraving on wood
Vitreous enamel, also porcelain enamel in US English, is a material made by fusing powdered glass to a substrate by firing, usually between 750 and 850 °C (1,382 and 1,562 °F). The powder melts, flows, and then hardens to a smooth, durable vitreous coating on metal, and also glass or ceramics, although the use of the term "enamel" is often restricted to work on metal, which is the subject of this article. Enameled glass is also called "painted". The fired enameled ware is a fully laminated composite of glass and metal. The word enamel comes from the High German word smelzan (to smelt) via the Old French esmail. Used as a noun, "an enamel" is a usually small decorative object, coated with enamel coating. Enameling is an old and widely-adopted technology, for most of its history mainly used in jewelry and decorative art. Since the 19th century the term applies also to industrial materials and everyday consumer objects, especially cooking vessels. "Enamelled" and "enamelling" are the preferred spellings in British English, while "enameled" and "enameling" are preferred in American English.
The ancient Egyptians applied enamels to pottery and stone objects, and sometimes jewelry,
Artworks:Untitled (Wheels and Suspended Double Pyramid 3B)
Weathering steel, best-known under the trademark COR-TEN steel and sometimes written without the hyphen as "Corten steel", is a group of steel alloys which were developed to eliminate the need for painting, and form a stable rust-like appearance if exposed to the weather for several years. (Wikipedia)
Found objects are often used in music, often to add unusual percussive elements to a work. Their use in such contexts is as old as music itself, as the original invention of musical instruments almost certainly developed from the sounds of natural objects rather than from any specifically designed instruments.
The use of found objects in modern classical music is often connected to experiments in indeterminacy and aleatory music by such composers as John Cage and Karlheinz Stockhausen, although it has reached its ascendancy in those areas of popular music as well, such as the ambient works of Brian Eno. In Eno's influential work, found objects are credited on many tracks. The ambient music movement which followed Eno's lead has also made use of such sounds, with notable exponents being performers such as Future Sound of London and Autechre, and natural sounds have also been incorporated into many pieces of New Age music.
Found objects have occasionally been featured in very well known pop songs: "You Still Believe In Me" from the Beach Boys's Pet Sounds features bicycle bells and horns as part of the orchestral arrangements.
Einstürzende Neubauten became known for incorporating a
Artworks:Light Box Cover for the Arizona Biltmore Hotel, Phoenix
Milk glass is an opaque or translucent, milky white or colored glass, blown or pressed into a wide variety of shapes. First made in Venice in the 16th century, colors include blue, pink, yellow, brown, black, and the white that led to its popular name.
First made in Venice in the 16th century, colors include blue, pink, yellow, brown, black, and white. 19th-century glass makers called milky white opaque glass "opal glass". The name milk glass is relatively recent. The white color is achieved through the addition of an opacifier, e.g. tin dioxide or bone ash.
Made into decorative dinnerware, lamps, vases, and costume jewelry, milk glass was highly popular during the fin de siecle. Pieces made for the wealthy of the Gilded Age are known for their delicacy and beauty in color and design, while Depression glass pieces of the 1930s and '40s are less so.
Milk glass has a considerable following of collectors. Glass makers continue to produce both original pieces and reproductions of popular collectible pieces and patterns.
A touchstone is a small tablet of dark stone such as fieldstone, slate, or lydite, used for assaying precious metal alloys. It has a finely grained surface on which soft metals leave a visible trace.
The touchstone was used in ancient Greece. Its role in the introduction of monetary economy was explored by science historian James Burke in the second episode of his 1978 BBC television series Connections.
It was also used by Indus Valley Civilization about 3500 BC for testing the purity of soft metals.
Drawing a line with gold on a touchstone will leave a visible trace. Because different alloys of gold have different colors (see gold) the unknown sample can be compared to samples of known purity. This method has been used since ancient times. In modern times, additional tests can be done. The trace will react differently to specific concentrations of nitric acid or aqua regia, thereby identifying the quality of the gold. Thus 24 carat gold is not affected but 14 carat gold will show chemical activity.
ASCII art is a graphic design BUALSSSS1111!!!! computers for presentation and consists of pictures pieced together from the 95 printable (from a total of 128) characters defined by the ASCII Standard from 1963 and ASCII compliant character sets with proprietary extended characters (beyond the 128 characters of standard 7-bit ASCII). The term is also loosely used to refer to text based visual art in general. ASCII art can be created with any text editor, and is often used with free-form languages. Most examples of ASCII art require a fixed-width font (non-proportional fonts, as on a traditional typewriter) such as Courier for presentation.
Among the oldest known examples of ASCII art are the creations by computer-art pioneer Kenneth Knowlton from around 1966, who was working for Bell Labs at the time. "Studies in Perception I" by Ken Knowlton and Leon Harmon from 1966 shows some examples of their early ASCII art.
One of the main reasons ASCII art was born was because early printers often lacked graphics ability and thus characters were used in place of graphic marks. Also, to mark divisions between different print jobs from different users, bulk printers often used ASCII art to
The Autochrome Lumière is an early color photography process. Patented in 1903 by the Lumière brothers in France and first marketed in 1907, it was the principal color photography process in use before the advent of subtractive color film in the mid-1930s.
Autochrome is an additive color "mosaic screen plate" process. The medium consists of a glass plate coated on one side with a random mosaic of microscopic grains of potato starch dyed red-orange, green and blue-violet (an unusual but functional variant of the standard red, green and blue additive colors) which act as color filters. Lampblack fills the spaces between grains, and a black-and-white panchromatic silver halide emulsion is coated on top of the filter layer. Unlike ordinary black-and-white plates, the Autochrome was loaded into the camera with the bare glass side facing the lens, so that the light passed through the mosaic filter layer before reaching the emulsion. The use of an additional special orange-yellow filter in the camera was required, to block ultraviolet light and restrain the effects of violet and blue light, parts of the spectrum to which the emulsion was overly sensitive. Because of the light loss due to
Cast iron is iron or a ferrous alloy which has been heated until it liquefies, and is then poured into a mould to solidify. It is usually made from pig iron. The alloy constituents affect its colour when fractured: white cast iron has carbide impurities which allow cracks to pass straight through. Grey cast iron, or grey iron, has graphitic flakes which deflect a passing crack and initiate countless new cracks as the material breaks.
Carbon (C) and silicon (Si) are the main alloying elements, with the amount ranging from 2.1 to 4 wt% and 1 to 3 wt%, respectively. Iron alloys with less carbon content are known as steel. While this technically makes these base alloys ternary Fe-C-Si alloys, the principle of cast iron solidification is understood from the binary iron-carbon phase diagram. Since the compositions of most cast irons are around the eutectic point of the iron-carbon system, the melting temperatures closely correlate, usually ranging from 1,150 to 1,200 °C (2,102 to 2,192 °F), which is about 300 °C (572 °F) lower than the melting point of pure iron.
Cast iron tends to be brittle, except for malleable cast irons. With its relatively low melting point, good fluidity,
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. Under natural condition, the cotton balls will tend to increase the dispersion of the seeds.
The plant is a shrub native to tropical and subtropical regions around the world, including the Americas, Africa, and India. The greatest diversity of wild cotton species is found in Mexico, followed by Australia and Africa. Cotton was independently domesticated in the Old and New Worlds. The English name derives from the Arabic (al) qutn قُطْن, which began to be used circa 1400 AD.
The fiber is most often spun into yarn or thread and used to make a soft, breathable textile. The use of cotton for fabric is known to date to prehistoric times; fragments of cotton fabric dated from 5000 BC have been excavated in Mexico and the Indus Valley Civilization (modern day Pakistan). Although cultivated since antiquity, it was the invention of the cotton gin that so lowered the cost of production that led to its widespread use, and it is the most widely used natural fiber cloth in clothing today.
Current estimates for world
Engraving is the practice of incising a design on to a hard, usually flat surface, by cutting grooves into it. The result may be a decorated object in itself, as when silver, gold, steel, or glass are engraved, or may provide an intaglio printing plate, of copper or another metal, for printing images on paper as prints or illustrations; these images are also called engravings.
Engraving was a historically important method of producing images on paper, both in artistic printmaking, and also for commercial reproductions and illustrations for books and magazines. It has long been replaced by various photographic processes in its commercial applications and, partly because of the difficulty of learning the technique, is much less common in printmaking, where it has been largely replaced by etching and other techniques.
Traditional engraving, by burin or with the use of machines, continues to be practised by goldsmiths, glass engravers, gunsmiths and others, while modern industrial techniques such as photoengraving and laser engraving have many important applications. Engraved gems were an important art in the ancient world, revived at the Renaissance, although the term traditionally
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects. The process of filmmaking has developed into an art form and industry.
Films are cultural artifacts created by specific cultures, which reflect those cultures, and, in turn, affect them. Film is considered to be an important art form, a source of popular entertainment and a powerful method for educating – or indoctrinating – citizens. The visual elements of cinema give motion pictures a universal power of communication. Some films have become popular worldwide attractions by using dubbing or subtitles that translate the dialogue into the language of the viewer.
Films are made up of a series of individual images called frames. When these images are shown rapidly in succession, a viewer has the illusion that motion is occurring. The viewer cannot see the flickering between frames due to an effect known as persistence of vision, whereby the eye retains a visual image for a fraction of a second after the source has been removed. Viewers perceive motion due to a
Glass is an amorphous (non-crystalline) solid material. Glasses are typically brittle and optically transparent.
The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica (SiO2) plus sodium oxide Na2O from soda ash, lime CaO, and several minor additives. Often, the term glass is used in a restricted sense to refer to this specific use.
In science, however, the term glass is usually defined in a much wider sense, including every solid that possesses a non-crystalline (i.e., amorphous) structure and that exhibits a glass transition when heated towards the liquid state. In this wider sense, glasses can be made of quite different classes of materials: metallic alloys, ionic melts, aqueous solutions, molecular liquids, and polymers. For many applications (bottles, eyewear) polymer glasses (acrylic glass, polycarbonate, polyethylene terephthalate) are a lighter alternative to traditional silica glasses.
Silica (the chemical compound SiO2) is a common fundamental constituent of glass. In nature, vitrification of quartz occurs when lightning strikes sand, forming hollow, branching rootlike structures called
Laid paper is a type of paper having a ribbed texture imparted by the manufacturing process. In the 19th century its use diminished as it was largely supplanted by wove paper. Laid paper is still commonly used by artists as a support for charcoal drawings.
In pre-mechanical papermaking (from the 12th century into the 19th century), the laid pattern was produced by the wire sieve in the rectangular mold used to produce single sheets of paper. A worker would dip the mold into a vat containing diluted linen pulp, then lift it out, tilt it to spread the pulp evenly over the sieve, and, as the water drained out between the wires, shake the mold to lock the fibers together. In the process, the pattern of the wires in the sieve was imparted to the sheet of paper.
Modern papermaking techniques use a dandy roll to create the laid pattern during the early stages of manufacture, in the same way as applying a paper watermark. While in the wet state, the paper stock (a dilute dispersion of the cellulose fibers in water) is drained on a wire mesh to de-water the stock. During this process, a dandy roll with a laid mesh pattern is pressed into the wet stock, displacing the cellulose fiber. This
Artworks:Portrait after a Costume Ball (Portrait of Mme. Dietz-Monnin)
Metallic paint, also called polychromatic or (incorrectly) "metal flake" paint, is used on the majority of new automobiles sold. Metallic paint can reveal the contours of bodywork more than non-metallic, or "solid" paint, Close-up, the small metal flakes included in the paint create a sparkling effect.
Metallics nearly always consist of a base coat with a clear lacquer or urethane top coat for protection and extra gloss. Historically, it was difficult to achieve an invisible repair if the paint was damaged because it is critical at which angle the flakes in the paint lie. Modern techniques have more or less eliminated this problem.
Two rarer variations are pearlescent paint, which appears as subtly different colours depending on the angle and intensity of the light, and "flip" colours where the colour changes more radically (e.g. from purple to orange) depending on the viewing angle. Flip colours have been used by Nissan on some special bits, and are frequently associated with TVR cars.
A final variation, hardly ever used on automobiles but common on bikes and motorcycles, is "flamboyant" or "candy apple" paint. This consists of a metallic silver base coat covered with a
A pencil is a writing implement or art medium usually constructed of a narrow, solid pigment core inside a protective casing. The case prevents the core from breaking, and also from marking the user’s hand during use.
Pencils create marks via physical abrasion, leaving behind a trail of solid core material that adheres to a sheet of paper or other surface. They are noticeably distinct from pens, which dispense liquid or gel ink that stain the light colour of the paper.
Most pencil cores are made of graphite mixed with a clay binder, leaving grey or black marks that can be easily erased. Graphite pencils are used for both writing and drawing, and the result is durable: although writing can usually be removed with an eraser, it is resistant to moisture, most chemicals, ultraviolet radiation and natural aging. Other types of pencil core are less widely used. Charcoal pencils are mainly used by artists for drawing and sketching. Coloured pencils are sometimes used by teachers or editors to correct submitted texts but are more usually regarded as art supplies, especially those with waxy core binders that tend to smear on paper instead of erasing. Grease pencils have a softer crayon-like
Petrified wood (from the Greek root petro meaning "rock" or "stone"; literally "wood turned into stone") is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree or tree-like plants having completely transitioned to stone by the process of permineralization. All the organic materials have been replaced with minerals (mostly a silicate, such as quartz), while retaining the original structure of the stem tissue. Unlike other types of fossils which are typically impressions or compressions, petrified wood is a three-dimensional representation of the original organic material. The petrifaction process occurs underground, when wood becomes buried under sediment and is initially preserved due to a lack of oxygen which inhibits aerobic decomposition. Mineral-laden water flowing through the sediment deposits minerals in the plant's cells; as the plant's lignin and cellulose decay, a stone mould forms in its place.
In general, stem tissue takes less than 100 years to petrify. The organic matter needs to become petrified before it decomposes completely. A forest where such material has petrified becomes known as a Petrified
Photographic film is a sheet of plastic (polyester, PET, nitrocellulose or cellulose acetate) coated with an emulsion containing light-sensitive silver halide salts (bonded by gelatin) with variable crystal sizes that determine the sensitivity, contrast and resolution of the film. When the emulsion is sufficiently exposed to light (or other forms of electromagnetic radiation such as X-rays), it forms a latent (invisible) image. Chemical processes can then be applied to the film to create a visible image, in a process called film developing.
In black-and-white photographic film there is usually one layer of silver salts. When the exposed grains are developed, the silver salts are converted to metallic silver, which blocks light and appears as the black part of the film negative.
Color film uses at least three layers. Dyes, which adsorb to the surface of the silver salts, make the crystals sensitive to different colors. Typically the blue-sensitive layer is on top, followed by the green and red layers. During development, the exposed silver salts are converted to metallic silver, just as with black-and-white film. But in a color film, the by-products of the development reaction
Artworks:FREE BEER (The Act of Drinking Beer with Friends is the Highest Form of Art)
A refrigerator (colloquially fridge) is a common household appliance that consists of a thermally insulated compartment and a heat pump (mechanical, electronic, or chemical) that transfers heat from the inside of the fridge to its external environment so that the inside of the fridge is cooled to a temperature below the ambient temperature of the room. Cooling is a popular food storage technique in developed countries. Lower temperatures in a confined volume lowers the reproduction rate of bacteria, so the refrigerator reduces the rate of spoilage.
A refrigerator maintains a temperature a few degrees above the freezing point of water. Optimum temperature range for perishable food storage is 3 to 5 °C (37 to 41 °F). A similar device that maintains a temperature below the freezing point of water is called a freezer. The refrigerator is a relatively modern invention. It replaced the icebox, which was a common household appliance for almost a century and a half prior. For this reason, a refrigerator is sometimes referred to as an icebox.
Freezer units are used in households and in industry and commerce. Food stored at or below 0 °F (-18 °C) is safe indefinitely. Most household freezers
Tapestry is a form of textile art, traditionally woven on a vertical loom, however it can also be woven on a floor loom as well. It is composed of two sets of interlaced threads, those running parallel to the length (called the warp) and those parallel to the width (called the weft); the warp threads are set up under tension on a loom, and the weft thread is passed back and forth across part or all of the warps. Tapestry is weft-faced weaving, in which all the warp threads are hidden in the completed work, unlike cloth weaving where both the warp and the weft threads may be visible. In tapestry weaving, weft yarns are typically discontinuous; the artisan interlaces each coloured weft back and forth in its own small pattern area. It is a plain weft-faced weave having weft threads of different colours worked over portions of the warp to form the design.
Most weavers use a naturally based warp thread such as linen or cotton. The weft threads are usually wool or cotton, but may include silk, gold, silver, or other alternatives.
First attested in English in 1467, the word tapestry derives from Old French tapisserie, from tapisser, meaning "to cover with heavy fabric, to carpet", in turn
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite (often called TCP/IP, although not all applications use TCP) to serve billions of users worldwide. It is a network of networks that consists of millions of private, public, academic, business, and government networks, of local to global scope, that are linked by a broad array of electronic, wireless and optical networking technologies. The Internet carries an extensive range of information resources and services, such as the inter-linked hypertext documents of the World Wide Web (WWW) and the infrastructure to support email.
Most traditional communications media including telephone, music, film, and television are reshaped or redefined by the Internet, giving birth to new services such as Voice over Internet Protocol (VoIP) and Internet Protocol Television (IPTV). Newspaper, book and other print publishing are adapting to Web site technology, or are reshaped into blogging and web feeds. The Internet has enabled and accelerated new forms of human interactions through instant messaging, Internet forums, and social networking. Online shopping has boomed both for major
Tracing paper is a type of translucent paper. It is made by immersing uncut and unloaded paper of good quality in sulfuric acid for a few seconds. The acid converts some of the cellulose into amyloid form having a gelatinous and impermeable character. When the treated paper is thoroughly washed and dried, the resultant product is much stronger than the original paper. Tracing paper is resistant to oil, grease and to a large extent impervious to water and gas.
Tracing paper is named as such for its ability for an artist to trace an image onto it. When tracing paper is placed onto a picture, the picture is easily viewable through the tracing paper. Thus, it becomes easy for the artist to find edges in the picture and trace the image onto the tracing paper. Pure cellulose fiber is translucent, and it is the air trapped between fibers, that makes paper opaque and looks white. If the fibers are refined and beaten until all the air is taken out, then the resulting sheet will be translucent. Translucent papers are dense and contain up to 10% moisture at 50% humidity. This type of paper is roughly 25% lighter than regular paper.
The sizing in production will determine whether it is for
Artworks:The Bride Stripped Bare By Her Bachelors, Even
Varnish is a transparent, hard, protective finish or film primarily used in wood finishing but also for other materials. Varnish is traditionally a combination of a drying oil, a resin, and a thinner or solvent. Varnish finishes are usually glossy but may be designed to produce satin or semi-gloss sheens by the addition of "flatting" agents. Varnish has little or no colour, is transparent, and has no added pigment, as opposed to paints or wood stains, which contain pigment and generally range from opaque to translucent. Varnishes are also applied over wood stains as a final step to achieve a film for gloss and protection. Some products are marketed as a combined stain and varnish.
After being applied, the film-forming substances in varnishes either harden directly, as soon as the solvent has fully evaporated, or harden after evaporation of the solvent through certain curing processes, primarily chemical reaction between oils and oxygen from the air (autoxidation) and chemical reactions between components of the varnish. Resin varnishes "dry" by evaporation of the solvent and harden almost immediately upon drying. Acrylic and waterborne varnishes "dry" upon evaporation of the water