Glossary
waste mold
This term is used in two contradictory ways. In its most common use: a piece mold made from a model (usually of clay or wax) when the model must be broken apart (wasted) in removing it from the mold. The other use: a mold from which only one cast can be taken, because the mold must be broken apart and discarded in order to release the cast. This is how lost-wax casting is accomplished, for instance. The use of this term is highly problematic then, unless the user immediately explains the meaning intended.
gable
The triangular space on a building formed by the two angles of a pitched roof. Gables are integral elements in Queen Ann style and 17th-century Dutch domestic architecture.
gallon
A unit of liquid measurement (US) equal to four quarts, or to eight pints, or to 128 fluid ounces. To convert gallons into liters, multiply them by 3.7854. Abbreviated gal.
galvanized
Galvanizing is a process by which steel is coated with zinc to prevent rusting. Painting on galvanized steel requires a special primer.
gargoyle
A carved stone architectural element which serves as a waterspout on the wall of a building. Gargoyles are shaped as grotesque monsters or beasts, and were particularly popular on Gothic cathedrals.
Example: Chartes Cathedral, Chartes, France, begun c. 1145
gauge
To measure; or, a certain unit of measure. Often refers either to a device used to measure the thickness of sheet metal or thickness of wire, or to the thickness of sheet metal or wire expressed in terms of a standard system. (pr. gayj)
G-clamp
A rounded metal clamp, used to squeeze materials together by adjusting a screw thread, as when drilling, sawing, or gluing.
See Also: adhesives
gelatin
A material made from animal glue which is flexible when warm and can be used for mold-making. Gelatin has largely been supplanted for such uses by latex, silicones and polyurethanes.
See Also: adhesives
gesso
Plaster or a fine plaster-like material made of gypsum, which is also called whiting, used for sculptures. An especially versatile medium in reliefs, gesso can be either the material cast in a mold or the material of a mold, a material to be modeled, or carved, or attached to something else. When used for mold into which molten metal is poured, it must be hardened with sand as a grog. Gesso may also refer to such a gypsum material mixed with an animal-hide glue and used as a ground for painting. For this latter use, it is usually applied to the surface of a wood panel or sculpture to become the surface on which an artist paints. Used by Gothic and Renaissance panel painters, and used today. Like all other dusts, airborne gesso is hazardous to breath-- every user must wear an appropriate face-mask. (pr. jes'soh)
gilding
The practice of applying a thin coat of gold to a painting, sculpture, or piece of furniture. Gilding was heavily used in the work of Late Gothic Italian painters. These artists depicted, among other things, the halos of angels in gold, emphasizing the decorative surface of the panels.
Example: Duccio's Virgin and Child Enthroned with Saints, 1308-1311
See Also: fire gilding, oil gilding, water gilding
glare
A strong or annoying and unwanted light, such as reflected from glass covering a picture. Also, a garishness or gaudiness; something overly conspicuous or obtrusive.
glass
A hard material made of silicates and an alkali fused with other substances. It is brittle, transparent or translucent, and considered to be a supercooled liquid rather than a true solid. It solidifies from a molten state, in an amorphous rather than a crystalline structure. Oxides fused within or upon molten glass can produce brilliant colors. In prehistoric times objects were carved from natural glass such as obsidian and rock crystal. The earliest known manufactured glass is from Egypt, c. 2000 B.C. Much was produced by the artisans of the Roman empire. Following the fall of Rome, however, there was very little glass manufactured in Europe until the 10th century, when stained glass appeared. As in ancient times, glassmakers fuse their materials at high temperatures in fireclay containers. Then the molten glass is boiled, skimmed, and cooled several degrees so that it can be ladled or poured into molds and pressed, or blown, or drawn. In its final shape, the glass is annealed to relieve stresses caused by manipulation, then slowly cooled.
glass fiber
A light but durable sculpture material used to reinforce resin, and hollow cast concrete. Thin filaments of glass are bonded into thin, flexible sheets called mats, strips of tape, or a fine, loosely stranded rope known as roving.
See Also: fiberglass
glaze
A term used in ceramics to describe a thin coating of minerals which produces a glassy transparent or colored coating on bisqueware. The glaze is fixed by baking the bisqueware in a kiln. This makes the surface smooth, shiny, and waterproof. Also, a glaze can be a thin, translucent or transparent coat over a painting, sometimes meant simply to protect the paint underneath, but more often to add a veil of coloration to an area of a picture.
glitter
Sparkle. Also, small pieces of light-reflecting decorative material. And, by extension, superficial attractiveness.
glossy
Surfaces which are lustrous, shiny, extra smooth. For example, satin, polished metals, and typical glass surfaces are glossy, whereas rougher surfaces, fabrics, etc., are more matte or dull. Sometimes used to refer to superficiality.
glue size
Size crystals or powder mixed with water form a gelatinous solution which forms the binder for gesso. Glue size added to plaster retards the drying process, giving the plaster a longer working time.
gold leaf
An extremely thin foil made of gold. It is available in various colors, each with a different proportion of copper or other metal in the alloy. Leaf made of less expensive materials to resemble gold is sometimes referred to as gold leaf. Something to which gold leaf has been applied may be described as gilt.
goo
A creamy paste of cement mixed with water. Goo is the first coat applied to a mold in making a hollow cast concrete sculpture, and forms an even surface layer for the finished cast. Goo is also a brand name for a certain hand cleaning product.
gouache
A heavy, opaque watercolor paint, sometimes called body color, producing a less wet-appearing and more strongly colored picture than ordinary watercolor. Also, any painting produced with gouache. (pr. gwahsh)
gouge
A beveled chisel with a rounded, trough-like cutting edge, generally for carving wood. There are numerous types of gouges, including a V-tool for engraving the surface of wood. Many gouges are designed to be pushed by hand rather than by the hit of a mallet. To gouge is to make a scooping or digging action, as with such a chisel.
gradated wash
A wash that is light or thin in an area where little color has been applied, and gradually becomes darker or heavier into another area, where more color has been applied. A painting technique typically used with watercolors and inks, but possible with any thinned pigments.
See Also: gradation
gradation
A gradual, smooth, step-by-step change from dark to light values or from large to small shapes, or rough to smooth textures, or one color to another.
graffiti
A drawing or an inscription made on a wall or other surface, usually so as to be seen by the public. Generally regarded as vandalism-- defacing public or private property-- and illegal; it may also be regarded as a form of art.
Example: Jean-Michel Basquiat's Zydeco, 1984
graffito
A method in which a line is produced by scratching through one pigmented surface to reveal another.
gram
A unit of weight measurement equal to 0.001 kilogram. To convert grams into ounces (US), multiply them by 0.03527. Abbreviated g.
See Also: kilogram
granite
A hard, coarse-grained igneous rock largely consisting of mica, and quartz. It has been used for sculpture, monuments, and architecture by several civilizations. The name granite is sometimes used loosely to include related igneous rocks such as granodiorite.
granulate
A material which is rough and grainy. Or, to make a material rough and grainy. (pr. gran"yeh-layt')
graph
A diagram that exhibits a relationship, often functional, between two sets of numbers as a set of points having coordinates determined by the relationship. Also called plot. Pictorial types of graphs include the pie chart and the bar graph, often used to express the relationships between quantities, volumes, degrees, etc.
graphic arts (or graphic design)
Visual arts that are linear in character, such as drawing and engraving. Also, art involving printing and printmaking, much of it for commercial purposes-- for such things as packaging, advertisements, signage, books and magazines.
graphics
The arts which include illustrations, diagrams, or designs which are used for printed or commercial materials. This art emerged in the late 19th century with the development of advertising. Pop artists used the power of strong, graphic images in their paintings.
Example: Andy Warhol's Soup Can, 1961-2
graver
A tool used in engraving metal, wood, or stone. A knob-like wooden handle which holds a metal shaft having a sharp beveled point with one size of several possible shapes, either flat, round, multiple, or elliptical. It is generally designed to be pushed by the hand, although there is an electrical tool often called a graver, which has a rotating tip. Another name for graver is burin. Graver may also refer to the technique or style of an engraver's work.
gravure
French for engraving. There are several types of engraving, including copper-plate and wood-engraving, rotogravure and photogravure. In English, gravure has been used broadly to cover any or all of these several types. In the nineteenth and twentieth centuries, prints have been referred to as "art gravures" in order to distinguish them as art prints, rather than as merely commercial-grade prints. The line drawn between the two is a relatively subjective one. Seeing this term ON a print should raise suspicion that it is part of a huge edition, and/or for a relatively mass audience.
gray scale
The range of neutral values, or shades of gray in an image. The gray scales of scanners and terminals are determined by the number of grays, or steps between black and white, that they can recognize and reproduce.
greenware
Generally refers to unfired pottery, although sometimes the term is used to specify Chinese stoneware with a high-fired green glaze.
See Also: bone dry, leather-hard
grid
A framework or pattern of crisscrossed or parallel lines. When crisscrossed, lines are usually horizontal and vertical; and when lines are diagonal, they are usually at right angles to each other. Typically graph paper is a grid of lines. Things which are often gridded: tiles, tessellations, wire screens, chess boards, maps, charts, calendars, and modern street plans.
grind
To crush, pulverize, or reduce to powder by friction, especially by rubbing between two hard surfaces. Or, to shape or refine with friction. [For grinding to occur, bumping is required.]
See Also: abrasive
grisaille
A style of monochromatic painting in shades of gray, used especially for the representation of relief sculpture, or to simulate one. Achromatic painting. May refer to a gray underpainting, laid for subsequent color glazing. Also, a kind of paint which can be fired onto glass. (pr. greez-eye', or griz-eye')
Example: The Vices and Virtues of Giotto's fresco cycle at the Cappella dei Scrovegni, Padova, Italy, c. 1305
grog
Clay which has been fired and ground into fine granules, used as an ingredient in a clay body or as a base on which clay is worked or fired which allows the form to contract freely as it dries. It may also be used for molds and cores and for objects cast and modeled. When added to clay it raises its firing temperature and makes it more stable, but it can also alter its appearance. Sometimes sand is used as a substitute.
grotesque
Ornamental images intended for architecture. These Ancient Roman motifs were discovered in underground ruins, or grottos. Often they depict animals, monsters, and figures.
Example: Lukas Kilian's Neus Gradesco Buchlein, 1607
ground
A surface to which paint is applied or the material used to create that surface. A painting's ground is usually specially prepared on its support. Traditionally, for oil paint on canvas use a ground of oil and white pigment and on wood surfaces either an oil ground or gesso. Within a picture, ground may refer to a surrounding or background area. Also, in etching, it's an acid-resistant compound through which a design is drawn.
Example: Sam Francis often painted on ungrounded canvas.
grout
A paste cement or mortar used for filling and sealing gaps-- cracks, crevices and joints-- especially between tiles.
guilds
A group of artists, craftsmen, and tradesmen from the medieval period. The guilds were structured with layers of apprentices, journeymen, and masters.
Example: The competition for the doors of the Florentine baptistery was supported by the wool finisher's guild.
gum arabic (or gum acacia)
Hardened sap secreted by acacia trees, used as a binder for water-soluble pigments. Water-soluble gums, used as adhesive in glaze or colors.
gypsum
Calcium sulfate dihydrate, found in a variety of forms as natural deposits (such as alabaster), which when heated and deprived of its moisture forms the substance known as plaster of Paris. Gypsum rates an index of 2 on Mohs Scale of Hardness. (pr. jip'sum)
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