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N - O - P -Q - R - S - T - U - V - W - X - Y - Z

bstract art An art form in which the emphasis is placed on the arrangement of forms, lines, and colors to produce a desired effect. Although the forms are derived from physical objects they do not necessarily resemble them. Art that does not attempt to represent the appearance of objects, real or imaginary.

Accent To emphasize or accentuate a part of a picture by means of value, shape or color contrast.

Acetate    A transparent or semi transparent sheet in varying thicknesses, especially useful as an overlay in color separation. Used for friskets in retouching, animated drawings, displays, etc. Treated acetate is specially prepared so that it will take paint and inks.

Acetic acid An organic acid used in testing acid resistance of glass enamels.

Acid resisting Resistant to, but affected by, acids.

Acid polishing Means of polishing glass by immersion in a mixture of concentrated sulphuric and hydrofluoric acids.

Acrylics Thermoplastic and thermosetting types of resins or coatings. These are based on polymers or co polymers of acrylic and methacrylic acid.

Acutance 1) Resolution of a printed shape. 2) clarity of detail. 3) ability to hold edge.

Adhesion The molecular attraction exerted between the surfaces of materials in contact.

Advancing colors Colors which appear to come forward such as red, orange and yellow.

Aesthetic Pertaining to the beautiful, particularly in art.

Agate burnishes An agate tipped tool used in rubbing down and polishing silver and gold decorations.

Alcohols A class of solvents in addition to the hydrogen and carbon elements, as in hydrocarbon solvents. Alcohols also have oxygen, in the form of an OH group

Alkali resisting Resistant to, but affected by, alkalis.

Alkali A compound of metal containing an OH group. It is basic in chemical reaction and is measured at above 7 pH; acids are less than 7 pH. Any base of hydroxide having the following properties; solubility in water, the power of neutralizing acids, the property of altering the tint of many colors.

Alla prima "all at once" a very direct way of painting, with little or no reworking.

Analogous Colors closely related to one another, such as blue, blue green and green.

Aniline colors Brilliant colors derived from coal tar. (They tend to fad after a period of time)

Annealing point The temperature at which the internal stress is substantially relieved in 15 minutes.

Annealing The treatment of glass by controlled heating and cooling in order to remove strains.

Aquatint Etching process producing tonal effects.

Aarabic A gum used with paint and glaze as a binder.

Arc A portion of a curved line.

Aromatic solvents Organic liquids having a cycle or ring of hydrocarbon structure and KB values over 40. e.i. toluol and xylol

Art Anything produced by skill and taste that moves people to see beauty in it or experience emotions resulting from its impact on their senses and intelligence.

Art Nouveau A decorative style (1890's) with a preference for asymmetry, linearity, and flowing organic structure.

Art Deco A decorative style of the 1920's and 30's marked by bold geometric shapes and the use of plastic and steel.

Art Brut "rough" or "raw" works of art that are intended to be "free of artistic culture"

Ascenders The parts of lower case letters that project above the body, as in h, d, f, etc .

Ashcan School American realist painters who rejected officially approved styles and subject matter. Although identified as radicals, they usually avoided serious issues in their work, concentrating on the picture squeness of their subject.

Asymmetrical Not symmetrical or formal in balance. also see symmetry

Atmosphere A mixture of gases usually within a lehr or kiln. Also a unit for expressing pressure, equal to 14.7 pounds per square inch or 760 mm of mercury.

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Balance A pleasing arrangement of the different parts and opposing elements. In informal balance these parts or elements are not arranged symmetrically. In formal balance the parts are arranged symmetrically.

Ball mill Rotating cylinder in which ceramic materials are wet, or dry ground, generally using pebbles or porcelain balls as grinding media.

Balopticon A projector used by artists for enlarging or reducing photos, sketches, etc. It projects the image onto the drawing surface.

Balsam of Capaiba A natural resinous liquid used as a color vehicle.
banding Application of banded decorations to glass or ceramic items.

Banding wheel A revolving disk on which a decorator sets the ware while it is being banded. Can be self centering, and motor driven.

Barbizon school A group of 19th century French artists who delighted in landscape for its own sake.

Baroque An ornate dramatic style of the 17th and early 18th century.

Bias relief Sculpture or carving in which the forms project less than one half of their true proportions from the surface.

Batch The raw materials properly proportioned and mixed for delivery to a furnace.

Batch type furnace (periodic furnace) A firing kiln that is loaded with ware through its cycle and shut down for removal of the ware. See kiln and lehr.

Bauhaus A 20th century German movement urging that design of any object should be dictated by its function.

Belleek A fine glossy transparent type ware requiring a very light fire. (after Belleek, a town in northern Ireland)

Benday A process of breaking up solid areas unto dots, lines or patterns.

Bent glass Flat glass that has been shaped while hot into cylindrical or other curved forms.

Biscuit An unglazed piece of clay that has been fired.

Bisque Unglazed ceramic ware that has been fired once.

Bit (Binary Digit) The smallest unit of information in a computer.

Blank A glass or ceramic object to be decorated.

Bleed through The condition resulting from a color which comes through a second color that has been applied over it.

Bleed Printing a picture without leaving any margin between the picture and the page edge. also term to describe the over lap of one color over an adjacent block of color.

Blending A method of painting or drawing in which one color or tone merges into another. The process of incorporating or mixing one color with another one.

Blister A defect consisting of a bubble that forms during fusion and remains when the enamel solidifies. A bubble in a glass article.

Bloom A film which forms on glass, enamels or precious metals as a result of an atmospheric action. Bloom cannot be wiped or washed off.

Blurring A condition where the graphics are indistinct or appear out of focus.

Bond The degree of adherence to glass or ceramics of an unfired color.

Bone china A porcelain made without feldspar with the addition of bone ash.

Borate glass Glass in which the essential glass former is boron oxide instead of silica.

Borax glass Vitreous anhydrous sodium tetraborate ( Na2 B4 O7 )

Borosilicate glass Any silicate glass having at least 5% of boron oxide ( B2 O3 )

Bright gold A metalo organic compound of gold dissolved in suitable solvent systems, which furnishes a bright gold when fired on the ware.

Brilliance The combined effect of brightness, strength, and/or purity of color tone. Apparent color strength.

Bristle brush A hog's hair brush used for oil painting

Bristol board A drawing surface of fine tough flexible cardboard, available in a variety of thicknesses and surface finishes.

Burn off Removal of organic media from applied colors in a kiln.

Burnish gold A suspension of gold particles which must be polished or burnished after firing to produce gloss.

Byte A unit of measure equal to eight bits of digital information
( 2 ). the standard unit measure of file size.

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Calcine To heat a ceramic batch material or mixture to a temperature below the melting or fusion point causing loss of moisture and /or other changes.

calibration bars On a negative, proof or printed piece, a strip of tones used to check printing quality.

Calibration Setting equipment to a standard measure to produce reliable results.

Calligraphy The art of elegant writing or penmanship.

Cameo paper Paper with a dull, smooth finish used for carbon and graphite pencil drawings.

Camera lucida An instrument with prism lenses, used for reducing or enlarging art work. An image of the art appears to be projected on to the drawing surface and can be traced by the artist.

Camera ready art Any art work or type that is ready to be prepared for printing.

Canvas board Cardboard covered with cloth which is used as a painting surface for oils.

Canvas A cloth surface used for painting in oil usually made of linen or cotton.

Casting The act of pouring slip into a mould.

Ceramic Pertaining to products manufactured from inorganic non metallic substances which are subjected to high temperatures during manufacture or use.

Chamfer To remove sharp edges, as from a mold to reduce chipping.

Chiaroscuro A term used to describe light and shade effects in painting. Generally applied to a dramatic use of contrasting light and shade.

Chroma The strength and purity of a color, determined by its degree of freedom from white or gray; color intensity. Also referred to as saturation.

Classic A work of art of high order and acknowledged excellence.

Clear coat Protective coating applied over imprint to carry the color from the paper to the substrate. Also referred to as covercoat.

Coefficient of thermal expansion (linear) The change in length per unit length of material with 1 degree C. change in temperature.

Color symbolism The use of color to signify or suggest an emotion, idea or characteristic.

Color wheel A circular color diagram.

Color separation The division of an image into its component colors (each color a negative or a positive film) for printing.

Color transparency A full color photograph on transparent film.

Color proof A representation of what the final printed composition will look like.

Color correction The process of adjusting an image to compensate for scanner deficiencies or for the final printed composition.

Color scale A series of colors that exhibits a regular change or gradation in intensity, hue or value.

Color dimensions Hue, value, and intensity; the three ways of measuring any given color.

Color interval The degree of visual difference between two colors, measured in steps of hue, value, and intensity.

Combustion Burning or raid oxidation.

Complementary colors Any two opposite hues on the color wheel, such as red and green.

Cone A three sided pyramidal form of clay and chemicals made to bend at a specific temperature.

Continuous tone A copy or image containing a range of tones from light to dark such as found in photographs, which blend smoothly into lighter or darker adjacent tones without visible boundaries, and without being photographed through a halftone screen.

Contrast To make use of strong differences in form, line texture or color for emphasis. The degree of tonal graduation between highlight and shadow areas.

Cool colors Blues, grays and greens, not suggesting warmth, rather cool places, such as water, ice and sky.

Covering power The ability of any given amount of paint to cover what is underneath.

Crackle An intentional effect that is given to ware to heighten its age and give a particular design to the cracks and lines.

Crawl A pulling away of the enamel from the surface of the glaze or glass. Caused by: 1) grease or foreign matter on the ware. 2) colors which do not have correct physical characteristics.

Crawling A condition which occurs when a glaze becomes extremely viscous in its molten state. At this time , the surface tension forces that are present overcome the adhesion or wetting tension, and the glaze collects in heaps.

Crazing The cracking that occurs in fired glazed or other critical tensile stresses
create To produce organize, or invent a piece of art inspired by the inner personality and imagination of the artist, as contrasted with mere mechanical effort.

Crop To cut off. In preparing art for reproduction, to indicate where the picture edges should be.

Crosshatch Parallel lines drawn to cross other parallel lines to obtain the effect of tone.

crystal ice A crushed and sized flux or frit used in decorating.

CT (Continuous Tone) Computer term for a file format used for exchanging high level information.

Cubism A semi abstract style by which the artist aims to express a sense of structure through arrangement of geometric shapes derived from real objects. A movement begun in France in the first decade of the 20th century, which by rejecting naturalistic tradition revolutionized painting and sculpture.

Cullet Waste or broken glass, suitable as an addition to raw batch.

Cyan Blue green color, complimentary to red and one of the three primary subtractive pigment colors, the other two being yellow and magenta. Cyan reflects blue and green light, while absorbing red.

Cylinder press A printing press that prints by the action of a cylinder pressing the paper against the ink.

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Dada A movement (1916-1921) which expressed revolt against conventional values in art and life. Bizarre constructions and deliberately inartistic materials were favored.

De Stijl A 20th Dutch movement ("The Style ") that took abstraction to the extreme.

Decal, heat release A decal printed in reverse sequence and applied face down for transfer from carrier paper to substrate by means of heat and pressure.

Decal Abbreviated form of decalcomania, the French designation of a design printed on a special paper for transfer to a substrate.

Decal, water slide A decal, usually manufactured face up, which is release from its paper carrier by water and transferred in a lateral motion as a free film onto the substrate.

Decorated Adorned, embellished, or made more attractive by means of surface detail, using color and/or third dimensional effects.
definition 1) Resolution, and acutance of a printed shape against the substrate or background. 2) clarity of detail. 3) ability to hold edge. 4) A subjective measure of the overall quality.

Densitometer A devise sensitive to the density of light transmitted or reflected by paper or film.

Density The degree of opacity of a photographic image on paper or film.

Depth The illusion of distance or a third dimension in a picture.

Descenders Parts of lower case letters that descend below the main body, as in g, p, q, etc.

Devitrification A surface defect manifested by the loss of gloss as a result of crystallization. A change from a vitreous to crystalline state; crystallization in glass.

Dimple A small depression in an applied coating.

Ding An indentation that can be felt (such as a dent or nick)

Distortion Picturing a subject so that it appears changed or twisted out of its natural shape. Used in art to heighten emotional effect.

Dominant wavelength A calorimetric quantity used to designate hue. One of three quantities used in the C.I.E. specification of color.

Dot gain The tendency of the printed halftone dot to change in size at the moment of ink printing, thus changing the overall visual quality of the print. Due to a number of variables, the printed dot will be larger than its film counterpart. Also called Dot Growth or Dot Spread.

Dpi (dots per inch) A measure of the output resolution produced by printers, imagesetters or monitors.

Drop out halftone A halftone reproduction in which the screen dots are eliminated in white areas. Drop out halftones are also called highlight halftones
drop out A term used for the loss or the reduction of small highlight dots.

Dry foot Ware with no glaze on the foot. Leaving the base of any item unglazed.

Dry edging Rough edges and corners of glazed ceramic ware due to insufficient glaze coating.

Dunting The cracking that occurs in fired ceramic bodies due to thermally induced stresses. (cooling faster than ware can accommodate)

Duplex paper A special paper used in preparing decalcomanias. This consists of two sheets stuck together, the top sheet being thinner and having a special coating of water soluble gum.

Durometer An instrument for measuring the degree of hardness of rubber or plastic, as in squeegee blades or rollers. Hardness is described as Shore Durometer Hardness. Average hardness is 70 Durometer. Lower numbers indicate a softer material.

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arth colors Pigments such as ochre, Venetian red, Indian red, the siennas, or umber, all made from earth minerals

Earthenware A glazed or unglazed nonvitreous ceramic whiteware, having an absorption of more than 3%.

Edge acutance The sharpness of the printed image, controlled by the screen stencil, screen tension, ink thixotropy and related factors.

Edit element/numbers - Aromatic solvents Borosilicate ph


Ellipse The shape of a circle when viewed at an angle.

Elliptical dot A halftone screen dot with an elliptical rather than circular shape, which sometimes produces better tonal gradations.

Embossed A decoration in relief or excised on the ware surface.

Emulsion The coating of light sensitive material on film.

Enamel A mixture of frit and pigment in powder form, which is formulated for application to various substrates.

Englobe A slip or liquid clay used for decorating.

Entrapped carbon Dark carbon film between enamel film and glass, usually due to rapid fire or lack of oxygen in the lehr.

Essences Special thinners for use with luster and liquid bright precious metal compositions.

Etch To attack the surface of glass with hydrofluoric acid or other agents generally for marking or decorating.

Esters A class of organic liquids used as solvents which are products of reaction between organic acids and alcohols.

Expressionism A movement begun in Germany before WW1, which stresses the free expression of the artists emotion and reactions rather than the literal representation of things. These include distortion, aggressively stylized forms, violent and evocative color combinations.

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Faience ware Earthenware having transparent glaze.
fat A term applied to color and oil mixtures. If the mixture flows well, it is said to be fat.

Fauvism An early 20th Century movement stemming from impressionism, favored striking color contrasts, distortions and strong personal emotion in painting. (Fauves fr.. wild beasts)

Feldspar Fusible rock that can be added to clay.

Feldspar (feldspar) A mineral widely distributed and usually of a foliated structure, consisting of silica and alumina, with potash, soda, or lime. A principal constituent in all igneous and metamorphic rock, as granite, gneiss, porphyry, greenstones, trachyte, etc. There are several varieties, common feldspar or orthoclase is the type of acid group containing 7 10% potash. A large percentage of clays is derived from the decomposition of the felspars, including kaolin, an important material in the manufacture of pottery and porcelain

Fettle To remove fins, mold marks, and rough edges from dry, or nearly dry ware.

Film A transparent material coated with a light sensitive substance.

Film negative A piece of film with a reverse image, in which the dark areas appear white and vice verse.

Fine art Art which is an end in itself and which is a personal expression of the artist who creates it.

Firing zone That portion of a lehr, through which the ware passes while remaining at, or near, the required firing temperature.

Firing time The period during which ware remains in the firing zone of a lehr to mature the coating.

Firing Fusing ceramic colors onto the substrate to which they have been applied. The controlled heat treatment of ceramic ware in a kiln or furnace during the process of manufacture to develop desired properties.

Firing temperature The peak temperature reached in a cycle. It may be expressed as lehr (or air) temperature or, if measured, actual ware temperature.

Firing cycle The time/temperature curve in a lehr or kiln.

Firing range The range of firing temperature within which a ceramic composition develops properties which render it commercially useful. The time/temperature interval in which porcelain enamel or ceramic coating is satisfactorily matured.

Fish eye A circular defect in the printed ink, causing uneven disbursement of pigment resulting in non uniform deposit of color.

Fit Usually refers to the relation or affinity of the glaze and the clay body. If the glaze and the body shrink in different proportions while firing they will crack.

Flat tone An area of uniform or even value .

Float glass Glass which is manufactured by a process in which a ribbon of molten glass is floated on a bath of molten tin to obtain surface flatness and a high polish.

Flood bar A device on a screen printing machine or a press which moves the color so as to maintain a supply in front of the squeegee.

Flood coat The thin coating of ink applied to the top of the printing screen by the flood bar, prior to the printing stroke.

Flux A material or mixture that promotes fusion. (such as lead, lime, or borax)

Focal point Center of interest.

Foreshorten To shorten forms, figures or objects viewed at an angle, according to the laws of perspective.

Form The three dimensional shape and structure of an object or figure.

Four color process printing A method of reproducing full color art work by photographically separating the art into three subtractive primary colors; yellow, magenta, and cyan plus black and then printed through a set of color separated halftone screens to produce a wide variety of colors.

Frisket A semi transparent paper used to shield portions of the art while retouching.

Frit A smelted mixture of soluble and insoluble materials forming a glass which, when quenched in cold water, is shattered into small friable pieces. Frit is used in Aluminum enamels, glass enamels and overglaze colors.

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Gang up To group separate pieces of art to be printed together.

Glass An inorganic product of fusion which has cooled to a rigid condition without crystallizing.

Glass blowing The shaping of hot glass by air pressure.

Glass enamels Colored glass flux or enamel used to decorate glass

Glaze A mixture of complex borates and silicates, compounded to produce a covering for ceramic bodies when fired at specific temperatures.

Gloss The surface shine or luster of a ceramic glaze, enamel or other decorative coating.

Glost kiln A kiln for firing glaze on ceramic ware.

Glost fire To kiln fire bisque ware to which glaze has been applied.

Gold caratage Measure of purity, or fineness of gold. 24 karats represents pure gold.

Gold eraser A material used for removing defects on fired gold without harming the ware.

Gouache French word for opaque water color.

Gradation A smooth gradual change of value, tint or color.

Graphic arts Pictorial arts, as in drawing, painting etc. on a two dimensional surface.

Grayscale The depiction of gray tones between black and white.

Green ware Formed ceramic articles in the unfired state.

Grog small particles of sand, bisque, or quartz that are added to a clay body to give it strength .

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Halftone A process for reproducing tonal images by photographing through a screen, in which details and light and dark tones are represented by dots of varying sizes in relationship to the tones and shades which they must reproduce. Small dots form light tones and larger dots form darker tones.

Halo Hazy area around a fired decoration.

Hardening on A heat treatment not in excess of 600 C. which fires organic matter in surface colorants onto ceramic ware.

Harmony A pleasing arrangement of the picture elements, due to similarity of one or more of their qualities, such as color size or shapes.

Haze A cloudy or frosty appearance on the surface of a precious metals decoration that usually can be wiped or washed off. see bloom

Heavy metals Generally toxic metallic elements contained in some pigmented materials, Ie. arsenic, chromium, cadmium, lead etc.

Highlight halftones A halftone reproduction in which the screen dots are eliminated in white areas. (also called drop out halftones)

Homogeneous Describes a substance that is uniform in its composition throughout its whole.

Horizon line An imaginary horizon line representing the height of the observers's vision.

Hue The name by which we distinguish a color, such as red, red orange, orange, green, purple etc. The first quality of a color distinct from its other characteristics, such as "value" and "intensity".

Humidity control A means of regulating the amount of moisture in the air by drawing through a condenser type unit which withdraws excess moisture, discharging the dried air for recirculation or conversely, adding water vapor to a given atmosphere when necessary.

Hygroscopic The quality of absorbing moisture.

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Imitation etch A fired on enamel which produces a matte or satin surface.
impervious That degree of vitrification evidenced visually by complete resistance to dye penetration.

Impressionism Late 19th century French school of painting based on the theory and practice of expressing broadly, simply and directly, visual impressions without minute analysis and detail. It favored the use of broken color technique.

Incised Decorated by cutting or indenting the ware surface inglaze decoration A ceramic decoration applied on the surface of an unfired glaze and matured with the glaze.

Inorganic pigment A pigment which is derived from mineral sources, some containing metal.

Intensity The degree of strength, saturation, or purity of a color. Also known as chroma.

Ishihara test A vision test for determining color blindness.

ISO The acronym for the International Organization for Standardization.

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Jigger A partly or fully automatic devise that looks like a potters wheel and is used to make plates by lowering an outline device onto the back of a revolving mold.

jolly Similar to a jigger, but used in production of cups.

juxtaposition The placement of colors or forms side by side or close together to accentuate each other.

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kaolin A clay.

key plate The plate to which all other plates are registered. Usually the black plate in a color series.

key A section of a scale of values or tones. "high key" indicates light values; "low key" indicates dark values.

kiln A furnace usually capable of temperatures higher than commonly used in lehrs.

kilo A unit of weight equal to 1.000 grams (2.2 lbs.)

kilobyte (K, KB) A unit of measure of digital information corresponding to 1024 bytes.

knockout A shape or object printed by eliminating (knocking out) all background colors.

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lacquers A family of various clear or pigmented synthetic organic coatings that typically dry to form an extremely durable and flexible film by evaporation of a volatile constituent or a solvent.

LAN (local area network) A group of connecting computers in a small area that share access to printers and other peripheral devices.

layout The art of organizing all of the elements to be printed; such as type, illustration and spacing, which have been carefully delineated. (for client approval)

leather hard Clay that is dry enough to hold its shape but damp enough to work with tools.

lehr A long tunnel shaped oven for firing or maturing a decoration.

linear perspective The science of representing objects in three dimensional space on a two dimensional surface.

liquid bright gold A complex organic resinate of colloidal gold, fluxes, organic resins, and organic solvents suitable for application to glass or china. Firing at high temperature develops a bright mirror finish. Liquid bright platinum and palladium are similar products.

liquid burnish gold Liquid bright gold modified with gold powder so that the fired film is thicker and can be burnished or polished.

lpi (lines per inch) A measure of the frequency of a halftone screen (55 to 200 horizontal and vertical lines).

luminosity A value corresponding to the brightness of a color.

luster A solution of organic pigments modified with suitable oils resins, and solvents which when fired produce an iridescent surface appearance on the ware.

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majolica A type of pottery with opaque white glaze and overglaze colored decorations. (in the tile industry, the term faience is used.

Mannerism A 16th century Italian style marked by the idealization of form and by extravagant effects.

matte finish Dull, satiny finish; not glossy or reflective.

mechanical Working guide for the printer which has all the elements shown in the layout pasted down in their correct positions.

medium The organic solvents and resins used as a vehicle and temporary binder in which the colors are empasted for printing to a substrate prior to firing.

megabyte A value of measure of stored data corresponding to 1,024 kilobytes, or 1,048,576 bytes.

mesh count The number of openings in a screen per linear inch.

micron One millionth of a meter (0.000001m). A term used to express the size of a pigment particle, used also to express the wavelength of light.

model The original creation from which a mold is made.

moire A pattern caused by superimposing one or more benday or halftone screens over another. (in printing, by misaligned screens).

mold A negative shape of the model which when cast with slip will make a hollow positive.

mono chrome picture A drawing or painting rendered in one hue but in which intensity and value may vary.

muffle kiln or furnace A kiln, or lehr, so constructed that the ware is not subjected to direct radiant heat from the elements (if electric fired) or to direct flame from the burners (if oil or gas fired).

Munsell color system A system of color analysis and identification in which color is said to have three components or measurable dimensions. They are hue, value, and chroma. Hue is the name of a color; red yellow or blue. Value measure the lightness or darkness of a color; a red, yellow or blue may be light or dark. Chroma measures the strength of a color; a light red hue may be weak or strong (also referred to as intensity).

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neutral color 1) color which lacks hue and intensity; Ie: black or the grays. 2) A color to which complimentary color has been added causing it to become relatively gray or brown. (Such a neutralized color may also be referred to as a tertiary color) 3) An earth color such as umber or a sienna.

nuance A subtle gradation.

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off contact The preset distance between the screen and the substrate that is to be printed.

Op Art An art form using the device of arbitrary patterns of shape, color and value to create optical illusions or effects to suggest movement.

opaque Having the quality of not permitting light to pass through; not transparent or translucent.

organic The term applied to any substances that are compounded from raw materials of animal or vegetable origin, but not mineral origin. It refers to chemical structures based on the carbon atom.

over glaze A complex compound of lead borosilicates or alkali borosilicates which is applied over a previously fired glaze, and then refired at approximately 1250 F to 1580 F. The overglaze material (liquid or in the form of a decal) is usually colored with inorganic ceramic pigment.

overlap To cover a part of one shape or line with another.

overlay A sheet, usually transparent and taped over the key art, on which are indicated the parts of the drawing to be printed in color. Also, a sheet containing instructions and taped over the original art.

oxide colors Inorganic or mineral based pigments used in porcelain and glass enamel colors.

oxidizing atmosphere A furnace atmosphere with an over supply of oxygen which tends to oxidize materials placed in it.

oxides Ceramic colors used for decoration, compound of = copper, cobalt, iron, manganese, etc.

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paint mill A mixing unit used to combine a vehicle with pigment in the manufacture of inks, by means of a succession of rollers through which the mixture passes.

pantograph A device used to reduce or enlarge pictures proportionately.

paste up See mechanical

PCE Abbreviation for Pyrometric Cone Equivalent.

peak firing temperature The highest temperature reached in a decorating firing cycle. To obtain a given result, the actual peak temperature.

perspective The means by which a sensation of three dimensional space is created on a flat picture surface.

petuntze (petuntse) A powdered form of feldspar or partially decomposed granite, used in China in the manufacture of porcelain.

pH (pH value) The ph scale is used to measure the acidity or alkalinity of a solution. The pH values run from 0 to 14, with 7 representing neutrality. Numbers less than 7 increase in acidity; numbers greater than 7 increase in alkalinity.

pica Printers unit of measure equal to twelve points, which is one sixth of an inch.

pigment Particles that absorb and reflect light and appear colored to our eyes. The substance that gives ink its color.

pin holes (pinholing) Small holes in the decoration extending through the color to the glass (or glaze).

pixel (picture element) The smallest distinct unit of a bitmapped image displayed on the screen.

PMS (Pantone Matching System) A commonly used system for identifying specific ink colors.

pointillism A technique of suggesting light effects by means of applying tiny dots of pure color to the canvas that are visually blended by the beholders eye, producing more vibrant color effects than if the pigments had been physically mixed together.

Pop Art A "popular" type of art in which common objects are reproduced or employed, such as consumer goods and comic strips.

porcelain A highly fired, fine, white translucent ceramic ware.

potters lead Transparent enamel composed of lead sulfide.

pottery A porous earthenware that may be glazed or not.

Postimpressionism Movement in painting advancing from impressionism toward composition based on the arrangement of solid forms.

ppi (pixels per inch) A measure of the amount of scanned information (the finer the optics of the scanner the higher the scan resolution).

PPM Abbreviation for " Parts Per Million".

primary colors In the additive color system, the primary colors are considered to be red, green and blue. In the subtractive color system, the primary colors are yellow, magenta and cyan.

primitive art Unsophisticated art characterized by an ignorance of, or disregard of, the laws of perspective, balance or other traditional art rules.

printing stroke The movement of the squeegee across the printing screen which has the function of forcing the ink through the stencil and screen to form the imprint on a substrate below.

process color reproduction A combination of halftone plates, usually red, yellow, blue and black, when printed in perfect register, superimposed on one another, combine to produce a full color reproduction.

progressive proofs In four color process work these proof sheets show the order of the printing and the shade of the inks.

proof A printed impression submitted for examination or correction.

PVC The abbreviation for Polyvinyl Chloride, a plastic used in the manufacture of some screen printing stencil materials.

pyrometer An instrument used to measure surface temperature; may utilize either the Fahrenheit or Celsius scales.

pyrometric cones small pyramidal shapes of ceramic materials used to measure the heat in a lehr. Designated by numbers as to temperature at which they will deform; several, each with different temperature numbers are usually used simultaneously.

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RAM (random access memory) - The memory a computer needs to store the information it is processing at any given moment. This is short term memory and is lost when the power is shut off.

rasterization The process of converting mathematical and digital information into a series of dots by an imagesetter for the production of negative or positive film.

realism A 19th century movement in many arts, directed or recording life objectively, with no idealization.

receding colors Colors which appear to move away, or create the illusion of distance; blue, green, and violet.

reducing atmosphere A furnace atmosphere which tends to remove oxygen from substances or materials placed in the lehr or kiln.

reflective art Artwork prepared so that it may be photographed or input into a computer by scanning.

refractory Nonfusible material capable of resisting high temperature.

register A means of printing more than one color, so that the second and all succeeding colors are printed in alignment with each other.

register marks Marks used to key an overlay to the drawing or mechanical, as in color separations. They insure that the various elements will be in register.

Renaissance The revival of classical art and learning in Europe during the 14th and 15th centuries.

reproduction Making one or more copies of an original piece of work.
resolution The relative ability of a stencil to form line pairs of acceptable acutance, at a minimum separation distance. Expressed in line pairs per inch. The ability to discriminate lines and gaps.

RGB (red green blue) The additive primary colors used for computer monitor displays.

rheology A science dealing with the deformation and flow of matter.

rheopectic The opposite of thixotropic, sometimes referred to as anti thixotropic, a characteristic associated with some resins.

RIP (raster image processor) Part of an output device that rasterizes information so that it may be imaged onto film or paper.

rosette The pattern created when all four color halftone screens are placed at the traditional angles.

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sagging The process of heating a sheet of glass placed on a form, causing it to take the shape of the form when exposed to appropriate temperatures.

sandblast A process of abrading glass by means of an abrasive (usually sand or alumina) driven by jet or air.

saturation 1) The degree of intensity of a color (see chroma), freedom of dilution with white. 2) The greatest degree of vapor that ambient air can hold.

sawtooth The effect of stencil material which tends to conform to the meshes of a

screen printing Fabric rather than the cleaner contours of the design on the film positive from which the stencil is produced. The filling in of the meshes produces a notched effect where lines of the design cross the fabric mesh diagonally.

scale Proportions or relative dimensions. To enlarge (scale up) or reduce (scale down) the size of a picture without changing the original proportions.

scanner A device used to digitize images to be manipulated, output, or stored on a computer.

screen angles The angles used to offset the different films in process color

separations Proper screen angles are critical to minimize moire patterns.

screen mesh The number of openings per linear inch of material.

scum Cloudy or frosty appearance on precious metals that cannot be removed.

secondary colors The three colors of orange, green, and violet, which lie halfway between the three primary colors of red, yellow, and blue (the theoretical colors obtained by mixing equal parts of any two primary colors.

shade A term descriptive of a lightness difference between surface colors with the other attributes of the color being essentially constant. A blended or graduated transition from one value to another. Also, a surface in shadow.

shading Lines, values or colors applied to a picture to create form, shadow or pattern.

shear The relative movement of adjacent layers in a liquid or plastic during flow.

shelf life (storage life) The period of time during which a product can be stored under specified conditions and still remain suitable for use.

short A term applied to mixtures of color and vehicles which lack flow.

silica (Silicon Dioxide) Usually quartz, the most common mineral in the majority of sands.

silk screen A method of printing through a stencil applied to a stretched screen of fine mesh fabric through which ink or paint is forced on to a printing surface of paper or board, leaving blank the areas covered by the stencil.

single fire The process of maturing an unfired ceramic body and its glaze in one firing operation. Term also used to describe the use of colors and precious metals in a single decal for overglaze firing.

sintering The formation of a solid mass by heating to fusion, but without complete vitrification.

sketch Unfinished drawing on any type of paper to give basic idea of a design.

slip sheet A sheet of waxed or treated paper placed between finished decals to prevent them from adhering to one another during shipment.

slip A water suspension of ground frit and mill additions which produce a liquid clay used for casting.

slurry A suspension of ceramic materials in a liquid.

soak period The time the ware remains at peak temperature in firing.

soft dot A type of dot in a halftone screen whose edge is not smoothly circular which can create a fuzzier image than a hard dot which has a smooth edge.

soft edge A blending or graduated transition from one value or color to another.

solvent A dissolving agent used to reduce viscosity. Specifically, a liquid that dissolves another substance.

spalling A defect characterized by chipping that occurs upon cooling due to either thermal shock or differential thermal expansion.

specification A clear and accurate description of the technical requirements for a material, a product or a service, which specifies the minimum requirements for quality and/ or construction for the acceptability of that material, product or service.

spectrum For visible radiation, the spectrum is a band of color produced by breaking white light into its component colors of red, orange, green, blue, indigo, and violet (the arrangement of colors side by side as refracted by a prism).
speed lines Extra lines following a moving figure or an object representing the disturbance this movement causes, used in cartoons.

sphere A form, all points on whose surface are equi distant from a point within called the center. A ball.

spit-out A glaze defect (pinhole type) occurring in the decorating kiln, resulting from minute gas bubbles from the body or glaze.

spot color -- Local addition of color in a defined shape and area.

square halftone One which has straight edges and squared corners.

squeegee A plastic or rubber blade used to force ink through the openings of a

screen printing stencil A tool for decal application.

starved glaze A glaze which lacks shine as a result of a thin
application or insufficient firing.

static Lacking in movement; the opposite of dynamic or active.

still life An artist's pictorial arrangement of inanimate objects.

stilt A tripod like setter fir glostware.

stipple Effect obtained by use of a series of dots or flicks in the drawing.

stoneware A vitreous or semivitreous ceramic ware of fine texture, made primarily from nonrefractory fireclay.

strip in To position copy not pasted up on the mechanical, in film, prior to plate making.

stylized Characterized by an emphasis on style and design rather than accuracy of representation.

subordination Subduing part of a picture to make it less important than some other part. The opposite of dominance.

substrate The base material or foundation over which another material is applied.

subtractive color A color produced by subtracting specific amounts of unwanted primary color from white light. The subtractive primary colors are yellow, magenta, and cyan and when the light of these colors are combined, they form black.

suggest To create a realistic impression of a subject without representing it in precise detail.

surface tension The property, due to molecular forces, by which the surface film of all liquids tends to bring the contained volume into a form having the least area.

Surrealism A 20th century art movement that explored the world of fantasy, dreams, and the subconscious.

symmetry Similarity of size, shape, and relative positions of parts on opposite sides of a dividing line.

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tangent touching In a picture when two forms or lines touch, or appear to touch, one another without overlapping, they are said to be tangent.

tempered safety glass Glass that has been strengthened by chemical tempering or by rapidly cooling from near its softening point.

tertiary color Any intermediate hue which contains some part of each of the three primary colors (red, yellow, and blue).

thermal conductivity Ability of a material to conduct heat.

thermal expansion An increase in size due to an increase in temperature expressed in units of an increase in length or increase in size per degree (e.g, inches/inch/degree C.)

thermal shock Sudden reduction or increase of temperature beyond normal rate of change under normal operating conditions.

thermocouple Two wires of different compositions welded together on one end to form a junction. On heating this junction, a low voltage, proportional to temperature, can be measured on the opposite ends.

third dimension Effect of depth or bulk achieved by the artist on a flat surface.

thixotropy That property of a color slurry which causes it to take a set on standing but will reliquefy when agitated.

three quarter view A view of an object halfway between a front and a side view. As three quartered portrait shows a head in a position approximately halfway between profile and full face.

three dimensional Possessing height, width, and depth. This is said of drawn objects that look solid, as opposed to flat.

throwing Making a form or shape on the potters wheel.

tint A mixture of pure color and white. A degree of color lighter than normal.

tonal Having graduations of tone or gray values.

tone A degree of color made darker than the original hue by adding its complimentary color or black.

tone A value. The predominating value of a picture, suggesting its key.

touch plate The use of an additional screen to print a tone or a tint of color of over existing color in process printing.

transfers A European term for decalcomania.

translucent The property of a material that permits light to pass through it but does not permit objects to be clearly seen.

transparency A film positive, either black and white or color.

trapping A prepress technique which allows for variation during press run. Done primarily by allowing an overlap between abuting colors.

trompe l'oell French for "deceiving the eye" An extraordinarily detailed type of realism.

two dimensional Flat without thickness, depth or solid form; having only the dimension of width and height.

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UCR (under color removal) A technique for reducing the amount of any process colors in neutral areas and replacing them with an appropriate amount of black.

underglaze decoration A ceramic decoration applied directly on the (bisque) surface of the ceramic ware and subsequently covered with a transparent glaze.

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value A quality by which a color can be classified as equivalent in lightness to some member of a series of grey samples ranging from white to black (the lightness or darkness of a tone or color).

value scale A compete range of values from white to black.

vanishing point A point in perspective drawing toward which receding parallel lines converge.

vibrating colors Contrasting colors of the same value placed side by side, causing an apparent vibration or "jump" between them.

vignette A photo or halftone so prepared that it has an irregular outside edge fading gradually from tone to pure white.

viscosity A term used to designate the degree of fluidity, or internal resistance to flow, of a compound ranging between liquid and heavy paste (resistance of a fluid to flow).

viscous Describes a material that is thick, resistant to flow.

vitrify To change into a glass by heating.

vorticsm English movement arising in 1914 marked by the expression of energy through abstract forms.

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warm colors Colors associated with heat or fire; red purple, red, orange and yellow.

wash The application of diluted watercolor or ink thinned with water, generally brushed on broadly with a loaded brush.

weft The horizontal fibers that cross the warp from edge to edge (selvage to selvage).

wet film thickness The depth, usually expressed in mils or microns, of an applied coating measured immediately after application.

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xylography A general term for the process of producing a print from a wooden block.

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Zero group A group of Kinetic artists (1957 Germany) whose aims included the direct use of movement and light in art, and the intervention by artists into the environment stressing the importance of working with nature. Unlike other Kinetic groups of the period, they valued the intrusion of the irrational and the subjective and individual identity.

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Glossary of Decorating Terminology SGD 1972, 1976, 1982 Technical
Glossary from Screen Printing Art Dictionary Random House Glossary of
Ceramic Tile 1994, Famous Artist Dictionary, Practical Book of

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