Glossary
enamel
A vitreous, usually opaque, protective or decorative coating made from silica heated in a kiln or furnace, and fused on to metal, glass, or ceramic ware. It is often applied as a paste which solidifies during firing as areas of color. Also, an object, usually very small, having such a coating, as in a piece of champlevé, cloisonné, bassetaille, or plique-a-jour. In ceramics, specially prepared low-firing colors with a high flux content.
C.P.
Chemically pure. This designation is sometimes applied to commercial pigments which are entirely free of extenders or any added inert pigments.
cadmiums
A metal found in several compounds: cadmium oxide, cadmium carbonate, cadmium chloride, cadmium sulfate, and cadmium sulfide. In paints, inks, enamels, glazes, and dyes, brilliant and permanent pigments are prepared from cadmiums, mostly cadmium sulfate. It is also used in electroplating, in solder for aluminum, as a constituent of easily fusible alloys, as a deoxidizer in nickel plating, in process engraving, and in nickel-cadmium batteries. Cadmiums are toxic.
calcagnolo
A claw chisel with two long points. This is the Italian name for what in France is called a pied debiche.
See Also: bush hammer
calendering
In paper-making, the process of pressing paper in order to give it a smooth surface, running it between rollers under strong pressure. Supercalendering produces an even smoother, polished finish.
caliper (or calipers)
An instrument used to measure thickness or distance, consisting of two metal or wooden arms with curved, pointed ends, hinged together; or having a fixed and a movable arm on a graduated stock.(pr. cal'e-per)
calligraphy
Careful hand lettering, or the decorative art of lettering in an ornamental style using brushes or pens.
calotype
An early photographic process, it was patented in 1840 by William H.F. Talbot (English, 1800-1877), the first process to employ a negative to produce a positive image on paper. Also known as Talbotype.
camaïeu
A painting technique, in which the painter creates a monochromatic image by employing two or three tints of a single pigment without regard to local or realistic color. Or, a woodblock print that imitates highlighted drawings on tinted paper.
cameo
A small-scale low relief in a stratified or banded material, usually a gemstone such as onyx or sardonyx, but also in calcite alabaster or shell or glass, in which the ground is of one color and the figure in relief in another color or colors.
camera lucida
A device much like an opaque projector, which replaced it, using a prism and mirrors to project the image of an external object onto a flat surface so that its image may be traced. Replacing the camera obscura, it was invented in the 17th century, but not widely used until the 19th. Literally, "lighted room."
camera obscura
The origin of the present day camera. In its simplest form it consisted of a darkened room with a small hole through one wall. Light rays could pass through the hole to transmit onto a screen, an inverted image of the scene outside. It was first mentioned by Aristotle in the fourth century BC, and developed through the centuries as an aid to drawing. Literally, "dark room."
See Also: camera lucida
canvas
Commonly used as a support for oil or acrylic painting, canvas is a heavy woven fabric made of flax or cotton. Its surface is typically prepared for painting by priming with a ground. Linen-- made of flax-- is the standard canvas, very strong, sold by the roll and by smaller pieces. A less expensive alternative to linen is heavy cotton duck, though it is less acceptable (some find it unacceptable), cotton being less durable, because it's more prone to absorb dampness, and it's less receptive to grounds and sizings. For use in painting, a piece of canvas is stretched tightly by stapling or tacking it to a stretcher frame. A painting done on canvas and then cemented to a wall or panel is called marouflage. Canvas board is an inexpensive, commercially prepared cotton canvas which has been primed and glued to cardboard, suitable for students and amateurs who enjoy its portability. Also, a stretched canvas ready for painting, or a painting made on such fabric.
canvas scraper
A tool used to scrape oil or acrylic paint from a canvas. A canvas scraper has a curving blade so that its effect is evenly distributed, avoiding cuts and grooves.
capital
An architectural element which acts as the crown of a column. The architectural orders are based on the various styles of capitals.
Example: Papyrus, Cushion, and Still-Leaf are all styles of capitals.
carbon
A common non-metallic element that occurs in many inorganic and in all organic compounds, exists freely as graphite and diamond, and as a constituent of coal, limestone, and petroleum, and is capable of chemical self-bonding to form an enormous number of chemically biologically, and commercially important molecules. It is an important ingredient in steel and other alloys. Its elemental symbol is C; atomic weight 12.01115. The specific gravity of amorphous carbon is 1.8 to 2.1, of diamond 3.15 to 3.53, and of graphite 1.9 to 2.3. Also, may refer to a sheet of carbon paper, or an image produced by marks made to carbon paper.
carbon dioxide
A colorless, odorless, tasteless, non-explosive and inert gas, CO2, formed during respiration, combustion, and organic decomposition and used in food refrigeration, carbonated beverages, inert atmospheres, fire extinguishers, and aerosols. Tank sizes available are 20 and 50 pounds. Also called carbon dioxide, carbonic acid, and, in aqueous solution it's called carbonic acid gas. Solid carbon dioxide, or dry ice, is a refrigerant. Toxic if inhaled in large amounts.
carbon paper
A paper that is coated on its underside with a dark pigment, and used to transfer writing and drawing to other surfaces. When marks are made with sufficient pressure upon its upper side, their likeness is transferred to the surface placed below the carbon paper with the pigments from its underside.
See Also: transfer paper
carborundum
Another name for silicon carbide, this is a hard crystalline substance used as an abrasive and in refractory compounds.
See Also: corundum
card stock
Card in the form it is received from a manufacturer, or a stored supply of card.
See Also: paper
cardboard
A stiff paper which may be of any of many thicknesses, typically made of pressed paper pulp or pasted sheets of paper. Sometimes cards are made from plastics. Cardboard has many uses. For example, it is employed as a material in making two- and three-dimensional work, and as a surface on which to mount other work. Card may also refer to a greeting card, post card, business card, playing card, trading card, credit card, etc. In the fiber arts, to card is to comb out fibers with a wire brush (also called a card).
See Also: bristol board, carding, card stock, foam core, matboard
cardboard relief
A collage made up of pieces of cardboard. Cardboard reliefs can be used in relief block printing.
carding
Combing out fibers with a wire brush, usually in preparing fibers for spinning. Also, combining fibers between two such brushes for the same purpose.
caricature
A representation in which the subject's distinctive features or peculiarities are deliberately exaggerated to produce a comic or grotesque effect. Also, the art of creating such representations. It is most common in drawings and editorial cartoons, but Honoré Daumier (French, 1808-1879) made several sculptural examples.
carrageenan
Sold in a powdered form, this seaweed-based material is used to size paper before marbling to keep the colors from running and bleeding, or used as a bath to float marbling colors on. It is also referred to as Irish moss.
carte de visite
Separate photographs made on a single negative and mounted on a card the size of a standard calling card. In the 19th century, this was an inexpensive means of creating mass-produced prints (pr. kart duh-vee'zeet")
cartoon
A kind of drawing done to get people thinking, angry, laughing, or otherwise amused, often accompanied by a caption. A cartoon usually has simple lines, uses basic colors, and tells a story in one or a series of pictures called frames or panels.
cartridge paper
A British term for almost any inexpensive paper. These may be of almost any weight or finish. Such paper is unlikely to be of archival quality, because it is probably not acid-free. Cartridge paper is typically used for sketches.
carving
The technique of cutting and abrading the surface of a block of material to shape it into a particular form. Among the materials appropriate for carving in schools include clay, chalk, plaster, soft salt blocks, artificial sandstone, soap, and wax.
See Also: subtractive, erasure, hollow carving, modeling, sculpture, solvent, marble
casein engraving
A technique in which a piece of Masonite board is built up to about 1/16 inch thickness in multiple layers of casein. This is then used as a plate for engraving. The engraved surface should be sealed before inking.
casein paint
A paint much like opaque watercolors in which casein-- a milk glue-- is its binder. Casein is a white, tasteless, odorless protein precipitated from milk by rennin. Casein is the basis of cheese, and is used to make plastics, adhesives, and foods, as well as paints. Casein paint can be used on paper or board for light impasto, for underpainting, wall decoration, etc. Casein paint is too inflexible for use on canvas. It dries quickly with a waterproof surface, and may be varnished.
cast
To form (molten metal, or liquid plaster or plastic, for example) into a three-dimensional shape by pouring into a mold; or something formed by this means. Also, an impression formed in a mold or matrix.
See Also: hollow casting, lost wax casting
catalyst
A substance which provokes a chemical reaction in other materials without itself changing. For example, an egg will emulsify water and oil by acting as a catalyst. In resin sculpture, a catalyst must be added in order to cause the resin to harden. An accelerator, usually already added to the resin, reacts with the catalyst and heat is generated which sets off the hardening process.
caustic
Corrosive. Be careful to read all warning labels, and take all precautions necessary with materials noted as caustic.
See Also: toxic
celadon
A ceramic glaze containing iron. It must be fired by the reduction method, with its red iron oxide (ferric) reduced to black (ferroso-ferric). The final color of the glaze is either olive green, gray-green, or gray. Celadon ware was developed and perfected during the prosperous Sung [or Song] dynasty (960-1279). It was valued by the Chinese largely because of its resemblance to jade. The pigment known as celadon green is also called green earth, the main ingredient of which is celadonite, an iron silicate. Chinese and Korean celadon porcelain was named for the resemblance of its color to this pigment. The word originated as the name of a character in the 1610 story by Frenchman Honoré d'Urfé, L'Astrée.
cellocut
In graphic arts, a plastic plate-- typically acetate, Lucite, or Plexiglas. Or, a plastic varnish used to add thickness to or texture a design.
cellophane
A thin, flexible, transparent acetate film available in colorless as well as colored sheets and rolls. It is made from cellulose, generally obtained from wood pulp. Cellophane was originally a trade mark, but is no longer.
See Also: acrylic plastics, cell, plastic
celluloid
One of the earliest invented plastics, celluloid is used form photographic films. It is a cellulose nitrate which is tough and flammable, generally obtained from wood pulp.
cellulose
A substance obtained from plant cells, which is one of the basic materials used in the manufacture of plastics.
cement
A powdered substance made by grinding calcined limestone and clay, which can be mixed with water and poured to set as a solid mass or used as a binding ingredient in mortar or concrete. Sometimes called Portland cement after an important early site of its manufacture. Also, may refer to substances that harden to act as an adhesive; glue, or to glue. (pr. se-ment')
See Also: aggregate
centimeter
A unit of distance measurement equal to 1/100 of a meter, or to 10 millimeters. To convert centimeters into feet, multiply them by 0.03281; to inches, x 0.3937. To convert cubic centimeters into cubic inches, multiply them by 0.06102; into pints (US liquid), x 0.00211. Abbreviated cm.
centrifugal casting
A means of casting employing the force achieved in a spinning apparatus to push the casting material into a mold. (Refers to centrifugal force-- moving away from an axis; the opposite being centripetal force-- moving toward an axis.)
ceramics
Pottery or hollow clay sculpture fired at high temperatures in a kiln or oven to make them harder and stronger. Types include earthenware, porcelain, stoneware, and terra cotta.
chalk
Pigments mixed with gum and pressed into a stick form for use as crayons. Pastel is similar, but less tightly bound.
chamfer
To cut through the thickness of a material at an angle, giving a sloping edge. Also, an oblique face or bevel cut at the corner of a board or post. Or, to cut grooves or fluting into an edge, such as the furrows or grooves in a column.
champlevé
A engraved, etched, or otherwise grooved area on metal that is filled with enamel. Once fired, the enamel is polished down.
See Also: cloisonné
chaplet
In lost-wax casting, a core pin or refractory spacing block connecting the core placed within a wax model to its surrounding mold. There are often many employed for each work, and may vary in size from thin wire to thick bars of metal, depending on the scale of the model. When the wax is melted from the mold, the chaplets keep the core from shifting. When molten metal is poured in, they are incorporated into it, and when the investment is broken off, they protrude from the surface of the metal. When they are made of the same alloy as the cast, they are difficult to find once they have been filed down. If they fall out when the core is removed, they leave holes which must be filled.
chasing
The process of finishing and refining a metal surface of metal object 's surface by denting rather than engraving it with steel tools such as tracers, ciselets, punches, and matting tools. Chasing might be done in order to remove the imperfections and rough spots on a bronze cast which necessarily form in the casting process. Chasing might also be done in order to ornament metal surfaces by embossing or hollowing with tools.
See Also: beader
cherub
Within the hierarchy of celestial beings, a cherub is a winged angel-child. Cherubs, or putti, were popular images in the Renaissance and Baroque periods.
Example: Andrea del Sarto's Madonna of the Harpies, 1517
chiaroscuro
A word borrowed from Italian ("light and shade" or "dark") referring to the modeling of volumes by depicting light and shade by contrasting them boldly. This is one means of strengthening an illusion of depth on a two-dimensional surface, and was an important topic among artists of the Renaissance.
Example: Leonardo da Vinci's Virgin of the Rocks, c. 1485
chisel
A cutting tool consisting of a metal shaft beveled at one end to form the cutting edge. A chisel is specially designed for cutting a particular material-- wood, metal or stone.
See Also: adze, chipping out, ciseau, ciselet, drove, gouge, pick, point
chroma
One aspect of colors (other than those in the black-white scale): hue and saturation, or degree of vividness.
chromatic pigments
All the pigments which are neither black, white, nor gray--the achromatic pigments.
See Also: chroma
chrome
A hard, brittle, bluish-white metal used chiefly in stainless steel and for electroplating other metals. Although chromium is an element, chrome can be either pure chromium or an alloy of it. Chromium's elemental symbol is Cr; atomic number 24; atomic weight 51.996; melting point 1,890°C; specific gravity 7.18; valence 2, 3, 6.
chromolithography
A lithographic process using several stones or platesone for each color, printed in register. The result is color prints, to be distinguished from colored prints that have the color hand-applied after printing.
chuban
In Japanese art tradition, a size of paper, used for prints, measuring c. 11 x 8 inches, sometimes smaller.
chum
A metal turning lathe attachment for placing leather-hard hollow ware over to hold it while turning. Also applies to a turned dome of clay, over which leather-hard articles are placed, prior to turning.
cinnabar
A red. Literally, red mercuric sulfide, sometimes used as a pigment. It is the ore from which mercury is derived.
circular saw
A circular toothed blade which is power driven. A bench circular saw is used for cutting timber by feeding the wood into the blade, to cut across or down the length.
See Also: carving, crosscut saw, ripsaw
circumference
The length of a line which is at the outside edge of a circle; periphery of a circle. Mathematical formula for circumference of a circle: two times pi (3.14159), or diameter times pi.
circumscribe
To draw a line or lines around something; to encircle, as when enclosing (perhaps a polygon or polyhedron) within lines, curves, or surfaces. To determine the limits of; to define or restrict.
ciseau
A chisel that cuts or engraves the surface of metal. From the French, and distinguished by them from a ciselet. (pr. see-zoh')
ciselet
A chasing chisel or tracer which dents rather than cuts a metal surface. From the French, and distinguished by them from a ciseau. (pr. see'zeh-lay")
cissing
In painting, an application of color that would have resulted in a flat area of paint (covering with an even thickness), but resulted instead in running streaks and bare spots, usually because of poor wetting of the surface. (pr. kissing)
cladding
A decorative, protective, or insulating layer attached to the outside of a building or other structure. Various metals and stones are often used for cladding. Examples include steel, aluminum, limestone, and marble. Also, a technique of construction with wood: a solid shape is formed by bending thin sheets of Masonite or plywood over a wooden framework.
See Also: veneer
clamp
In architectural construction, a device, usually metal, used to hold together blocks of stone of the same course. Also called a cramp.
claw chisel
A stoneworking chisel with the blade fashioned into small teeth. It is used for shaping and leaves striations in the stone surface. A claw chisel with two long points is known as a calcagnolo (Italian) or as a pied de biche (French).
See Also: bush hammer
claw hammer
The head of a claw hammer has a flat striking face on one side and two heavy metal prongs on the other used to trap and lever out nail heads.
clay
Mud; moist, sticky dirt. In ceramics, clay is the basic material, usually referring to any of a certain variety of mixtures of such ingredients-- fine-grained, firm earthy material that is plastic when wet, brittle when dry, and very hard when heated. The most common types of ceramic clays are earthenware's (terra cotta is an example), stoneware's, and porcelain. Also, a hardening or no hardening material having a consistency similar to clay, often called modeling clay or plasticize.
clay body
A balanced blend of clay, minerals and other non-plastic ingredients which make up the pottery structure.
cloisonné
Enamels fused inside a wire enclosure (a cloison) on a metal or porcelain ground, forming chambers (cloisons) to receive vitreous enamel pastes. Used earliest and commonly by the Byzantines, with excellent examples dating from before the 11th century. A rarer type of cloisonné is that in which the wire enclosures surround inlaid stones. (pr. klwah'zo-nay')
CMYK
Cyan Magenta Yellow blacK. A system for reproducing color in print-- "four-color printing", creating the color spectrum using cyan, magenta, yellow, and black.
coarse
Of low, common, or inferior quality. Lacking in refinement or delicacy. Indecent or vulgar. Or, consisting of large particles, not fine in texture. Do not confuse it with course, which is pronounced identically. (pr. kohrs)
coat
A layer of material covering something else, which might also be termed a coating. Or, to cover with a layer, as of ink, paint, or silicone rubber. Something described as coating well is thoroughly opaque with the application of one layer.
cobalt
A metal resembling nickel from which a range of pigments is made. An example of a work in which cobalt was used for its color:
coils
Long, snake-like ropes of clay that are used in making pottery. The coil method of making pottery involves building the walls of a pot with a series of coils into the required shape. Once the desired height has been reached the surfaces can either remain coil-textured or they can be smoothed. Much pottery in primitive cultures was made this way, and remains one of the principle hand-building techniques potters use.
collage
A picture or design created by adhering such basically flat elements as newspaper, wallpaper, printed text and illustrations, photographs, cloth, string, etc., to a flat surface, when the result becomes three-dimensional. Introduced by the Cubist artists, it was widely used by artists who followed, and is a familiar technique in contemporary art. (pr. kuhl-lahzh')
collaring
Part of the ceramic technique of throwing a pot on a potter's wheel. Collaring is constricting the top of the pot to prevent the wet clay from flaring out. Not to be confused with a collograph.
collodion wet plate
A photographic process invented in 1851, involving the use of a thick glass plate on which to create a negative, exposing it in the camera with its emulsion still wet. Also called wet plate and wet collodion process. It was the standard photographic process for a time, replaced in the 1870s by the gelatin dry plate process.
collograph
A print made from an image built up with glue and sometimes other materials. The inked image is transferred from plate to paper and is simultaneously embossed. The name derives from collage. Not to be confused with a collagraph or a collotype.
collotype
A photographic printing process in which a glass plate whose surface has been coated with gelatin carries the image to be reproduced. Also called a photogelatin process.
color
Produced when light strikes an object and then reflects back to your eyes. An element of art with three properties: (1) hue or tint, the color name, e.g., red, yellow, blue, etc.: (2) intensity, the purity and strength of a color, e.g., bright red or dull red; and (3) value, the lightness or darkness of a color. Photographers measure color temperature in degrees Kelvin (K).
color correction
The process of altering colors as they appear in a digital image or in print to insure they accurately represent the work depicted.
color separation
A process used by commercial artists which separates the primary colors in a color picture. A printing plate is then made for each of the colors-- one for yellow, one for blue (cyan), one for red (magenta), and also one for black. When these colors are printed one on top of the other, the full color original picture is reproduced.
color temperature
Important in color photography, the color temperature of a source of light is measured in Kelvin units in order to match it to the appropriate film, sometimes using filters, some of which are assigned what are called decamired values. Kelvin units are often referred to by their abbreviation K.
color wheel
A radial diagram of colors in which primary and secondary, and sometimes intermediate colors are displayed as an aid to color identification, choosing, and mixing. The complement to each color is the color opposite that color on the color wheel.
compass
A mechanical tool that has two hinged, adjustable legs for drawing different sixes of circles and arcs. One of the legs has a sharp steel point that is placed on one spot on the paper. The other can hold either a pencil, a pen or a blade that rotates around the pointed end.
complementary colors
Colors that are directly opposite each other on the color wheel, such as red and green, blue and orange, and violet and yellow. When complements are mixed together they form the neutral colors of brown or gray. Note that this term is spelled differently than the word "complimentary," which means gift.
composition
The plan, placement or arrangement of the elements of art in a work, usually according to the principles of art. The design of a composition should either be pleasing or otherwise expressive.
Example: Painter Piet Mondrian is considered a master of composition.
composition leaf
An economical substitute for genuine gold or silver leaf made from brass or aluminum. Composition leaf may tarnish and should be protected by a final varnish.
See Also: gilding, leaf, fire gilding, oil gilding, water gilding
conté crayon
The common and brand name for a drawing medium comparable to colored chalk. It is available in several colors. Most common are red-brown (called sanguine, French for blood), black, grays, and white.
See Also: crayon
continuous representation
A technique popular in European Medieval art which shows stories from a narrative set side by side on a continuous background.
Example: Paolo Ucello's The Miracle of the Host, 15th century
contour
The outline of a shape which defines a form or figure. Sandro Botticelli is considered a master of line and contour with his whimsically drawn figures.
Example: Sandro Botticelli's Birth of Venus, c. 1482
contrapposto
The position of a human figure in painting or sculpture in which the hips and legs are turned in a different direction from that of the shoulders and head; the twisting of a figure on its own vertical axis. Especially a way of sculpting a human figure in a natural pose with the weight of one leg, the shoulder, and hips counterbalancing each other. Thus it is sometimes called "weight shift." This technique was developed late in the Greek period.
Example: Kritios Boy, c. 490 B.C.
contrast
A large difference between two things; for example, hot and cold, green and red, light and shadow. Closely related to emphasis, a principle of art, this term refers to a way of combining art elements to stress the differences between those elements. Thus, a painting might have bright colors which contrast with dull colors, or angular shapes which contrast with rounded shapes. Used in this way, contrast can excite, emphasize and direct attention to points of interest.
cool colors
Colors often associated with water, sky, spring, and foliage, and suggest coolness. These are the colors which contain blue and green and appear on one side of the color wheel opposite the warm colors. Psychologically, cool colors are said to be calming, unemphatic, depressive; optically, they generally appear to recede.
See Also: analogous colors
coping
A method of splitting away stone from a block preliminary to shaping a carving. Small punches are driven into a block and hit in sequence until the stone splits between them.
copper
A ductile, malleable, reddish-brown metallic element. It is used either pure or in alloys such as brass and bronze.
core
A hollow wax sculpture to be cast in metal is filled with clay or plaster with grog (refractory material). The wax can be modeled directly over a preformed core, and after the sculpture is cast, the core is generally removed in order to make the sculpture less heavy. A core might be either an original model pared down, or it might be poured into a hollow wax cast. A core may contain an armature, and it may hold chaplets.
See Also: direct casting, indirect casting, lost wax casting
core pin
A chaplet. In lost-wax casting, core pins connect the core placed within a wax model to its surrounding mold. Typically many are employed for a work. They vary in size from thin wire to thick bars of metal, depending on the scale of the model. When the wax is melted from the mold, core pins keep the core from shifting. When molten metal is poured in, they are incorporated into it, and when the investment is broken off, they protrude from the surface of the metal. When they are made of the same alloy as the cast, they are difficult to find once they have been filed down. If they fall out when the core is removed, they leave holes which must be filled. A possible substitute for core pins are refractory spacing blocks.
Corinthian
One of the three main architectural orders which describes the style of the capital of a column. The Corinthian column is decorated with rows of acanthus leaves, and is the most ornate order.
Example: The façade of Andrea Palladio's San Giorgio Maggiore, 1565
cornice
An architectural element which acts as the uppermost part of the entablature in Classical buildings. It is the molding crowning the outside of the structure.
Example: The buildings of the Acropolis in Athens, Greece all include cornices.
corundum
A very hard mineral, crystallized alumina or aluminum oxide, used as an abrasive and polish.
See Also: carborundum, emery
countersinking
A method of keeping the head of a screw or bolt, used to join sections of a work, below the outer surface of the materials.
cover
The capacity of a pigment to obscure an underlying surface; or, its hiding power. Alternatively, its capacity to extend by given volume over a surface.
crackle
In ceramic glazes, a network of fine craze lines, produced intentionally or accidentally, especially associated with oriental and modern porcelain. Also, in oil painting, when the paint's surface is broken by a network of small cracks.
See Also: crazing
craft
Technical skill, manual dexterity, considered apart from the fine arts, or from the cerebral, expressive, or aesthetic aspects of them. Also, any of the manual activities performed by artisans or craftspeople, as distinguished from the specific group of techniques that are practiced by artists in the making of fine art. Although there have been tensions resulting from differentiations between the art and the craft, especially since the onslaught of mechanization in the industrial era, support for the notion of craft has been undercut. However, there have been certain revivals and other movements which have served to counterbalance this trend.
crayon
Traditionally, any drawing material made in stick form, including chalk, pastel, Conté crayons, charcoal, lithographic and other grease crayons, as well as wax crayons. To children, the term invariably refers to these last sticks of color made of paraffin, and patented under various trade names, available in several sizes and shapes, either water-soluble or not, usually in a paper wrapper.
crazing
A network of cracks which sometimes forms in ceramic glazes; crackle. It may be desirable or not, depending on the artist's wishes. It is caused by the glaze and clay body contracting at different rates as they cool after firing. A similar pattern in the surface of oil paints is known as crackle instead of crazing. Crackle in oil paintings is less likely when the painter follows the rule of fat over lean -- when oil colors will be applied in layers (coats), the first layer should be leanest (least oil) followed by layers with progressively more fat (more oil.) Following this principle results in a work less likely to crack in aging. Similarly, in order to encourage crazing, later coats should have less oil than earlier ones. Desirable in crackle glazes, but not for functional earthenware.
crosscut saw
A saw with fine teeth set and angled to cut transversely through the grain of a dense material, usually wood.
See Also: circular saw, ripsaw
crucifixion
The image of Christ nailed to the cross. This was a popular image in the sixteenth and seventeenth-centuries.
Example: Masaccio's Holy Trinity, c. 1428
curvilinear
Describing the state of having curved lines.
Example: Spanish architect Antonio Gaudi's casa Mila, Barcelona, Spain, 1907
cyan
The blue-green subtractive primary color which absorbs red and transmits blue-green; that is, white light minus red.
cyanotype
A very direct photographic process resulting in monochromatic images in tints and tones of blue. It first appeared in 1842.
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