Glossary of Terms Evans Ceramics


The following is a brief glossary of terms and their definitions for our clay, ceramics, and pottery industry.

Glossary of Terms




The degree of moisture that will soak into plaster when casting, or into bisque when glazing or decorating with nonfired colors.
Accenting Refers to the process of emphasizing an area with lighter or darker colors, by shading or outlining.
Add-Ons Greenware parts that are added to the main casted piece (Example: handles to cups).
Adherence The ability of a fired or non-fired color to stay in place on a given surface.
Aging Refers to the process of allowing newly mixed casting slip to set, undisturbed, for several days. This process allows the ingredients to homogenize for best casting qualities.
Airbrushing The process of applying color with the use of a small air-pressure gun. Used for shading and general decorating.
Antiquing A decorating process in which you remove applied color to accentuate detail.
Antiquing Gels Nontoxic, nonfired, water-based colors that can be used to antique over all Duncan nonfired colors.
Antiquing Solvent A thinner for airbrushing nonfired, oil-based colors. Antiquing Solvent can also be used as a cleaner/conditioner for brushes used with oil-based colors.
Applique A type of ceramic add-on.
Banding Refers to applying color to ware in decorative bands. Usually done with the aid of a banding wheel.
Banding Wheel A hand-operated turntable used in banding and other types of decorating.
Binder Material, such as gum arabic, added to hold ceramic ingredients together.
Bisque Fired, unglazed objects of clay. Generally, bisque is clay that has been fired to a kiln setting of cone 04.
Blistering Refers to the appearance of broken bubbles found on the glazed surfaces of fired ceramic pieces.
Body The term used to describe any formula of clay. Often called clay body. The composition of any clay body will change depending on where the clay is mined.
Casting The process of filling a plaster mold with casting slip (liquid clay) to create a clay object. Once the plaster mold is removed, the clay object is known as greenware or unfired clay. (See pouring.)
Clay Carbon Carbonless paper used for transferring designs onto greenware (unfired clay).
Cleaning Greenware The process of removing mold seam lines and imperfections from unfired clay objects.
Cratering Refers to moon-like craters that may appear on a glazed surface.
Crawling Refers to a glaze defect in which the glaze pulls away or crawls away from the bisque, leaving bare bisque areas.
Crazing Refers to a glaze defect in which hairline cracks appear on a fired glaze surface.
Crosshatch A decorating technique that calls for applying alternate coats of color at perpendicular angles.
Decal A design, printed with ceramic colors on special paper, which can be applied to the surface of ware and fired for permanency.
Dipping A method of applying glaze by immersing a piece in a container of glaze.
Drybrushing An effect achieved by applying nonfired color very lightly with an almost dry brush.
Dryfooting Refers to leaving the bottom of a piece unglazed so that stilting is not necessary.
Embossment A raised design on a clay piece.
Ferrule The metal band of a brush just below the bristles.
Firing The process of maturing ceramic products by varying degrees of heat. Firing usually takes place in a kiln.
Flash The undesirable transference of a soft glossy sheen onto unglazed ware when high-fired glazed and unglazed ware are fired together.
Flashing Refers to shiny edges on ware, often produced by overfiring.
Flow The term used when referring to the running or moving qualities of a glaze.
Flowing Coat The term used to describe applying color with a well-loaded brush.
Foot Refers to the bottom of ceramic item.
Furniture are implements used to make full use of a kiln’s capacity (shelves, posts and stilts).
Glaze A fired finish consisting of a prepared mixture of frit that produces a glass-like surface when fired.
Glaze Brush A brush with long full hairs for the application of glazes and underglazes.
Glaze Butting The term used to describe placement of two or more glazes in proximity on the same piece.
Glaze Trailing Refers to the use of a fine-tip squeeze bottle to trail one glaze over another to create a design.
Graining The process of creating a wood-grained effect using thinned, nonfired colors applied in long, uneven patterns.
Greenware The term used for unfired clay articles.
Greenware Drill A small tool with a threaded point used for drilling holes in dry greenware.
Greenware Preparation The removal of mold seam lines and imperfections from unfired clay objects. (See Cleaning Greenware)
Greenware Saw A small tool having a serrated edge for cutting dry greenware.
Grit Cloth An abrasive cloth used for cleaning greenware or bisque.
Grit Sponge A square sponge that has an abrasive surface on one side.
Hard Bisque Ware that has been fired to witness cone 04 or hotter. (See Soft Bisque.)
Hard Spots Areas that will reject color, and sometimes cause ware to have bare spots. Commonly caused by improper greenware casting.
High-Fire Refers to ceramic articles or glazes that are fired to witness cone 4 or higher (stoneware and porcelain).
Immature Bisque Ware that has been fired cooler than witness cone 06.
Incising Refers to the technique of cutting a clay surface to create a design.
Kiln A heating chamber for hardening and maturing clay and glazes.
Kiln Furniture Implements used to make full use of a kiln’s capacity (shelves, posts and stilts).
Kiln Wash A coating used on the tops of kiln shelves and kiln floors to protect them from glaze drippings.
Lace Tool A long, pointed tool used when applying thin strands of clay.
Leather-Hard The term used to describe clay items that are damp but firm enough to handle without losing their shape.
Liner Brush A brush used for fine lines and design work.
Loading Refers to completely filling a brush with color.
Luster An overglaze that imparts an iridescent surface to the ware.
Majolica Technique Refers to applying underglazes in a design over an unfired, nonmoving glaze.
Maturing Point The temperature needed to mature glaze or clay.
Modeling Clay Prepared clay used for hand modeling.
Mold A hollow plaster-of-paris form in which articles are reproduced using clay slip.
Nonmoving Glazes Ceramic glazes that move or flow very little in the glaze firing.
Nontoxic The term used to describe paint products conforming to U.S. standard ASTM D-4236 to contain no materials in sufficient quantities to be toxic or injurious to humans.
Opaque Refers to nontransparent color.
Overglaze A decorative finish applied over a fired glaze surface and made permanent by firing.
Overglaze Compatible A glaze that will accept overglazes for a third firing. Glazes that contain copper for added color are not overglaze compatible.
Palette Knife A flexible knife with no sharp point used for mixing or stirring color.
Pinholes Tiny holes penetrating a glazed surface.
Plasticity Refers to the pliability of modeling clay.
Porosity Refers to the permeability of fired or unfired clay.
Posts Columns of refractory material used to support shelves inside the kiln. (See Furniture, Kiln.)
Pouncing A technique in which you apply color with quick up-and-down movements with a brush or sponge.
Pouring The process of filling a plaster mold with casting slip (liquid clay) to create a clay object. Once the plaster mold is removed, the clay object is known as greenware or unfired clay. (See Casting.)
Pyrometer An instrument that indicates temperature in the kiln.
Rolling Consistency Refers to the consistency to which glazes are thinned for rolling inside ware.
Rolling Glaze A method of covering the inside area of ware by rolling thinned glaze inside.
Running Refers to the fluidity of a glaze at the point of maturity before cooling and hardening.
Score Refers to the process of scratching tiny criss-cross lines on areas of greenware that will be fastened together with Duncan’s Patch-A-Tatch or clay slip.
Scrub-coat A priming coat of thinned opaque underglaze or glaze.
Sea Wool Sponge See Wool Sponge
Sealers Spray or brush-on coatings for use over nonfired colors to protect the surface and enhance the colors.
Seam A ridge formed in greenware where mold pieces join.
Sgraffito Refers to the process of creating a design in ware by gently scratching through applied color to reveal the color or the clay body beneath it or to create carved designs.
Shelf Supports are columns of refractory material used to support shelves inside the kiln. (See Posts, Furniture, Kiln.)
Shelves are flat slabs of special high-temperature materials on which ware is placed inside kilns. (See Furniture, Kiln.)
Shivering occurs when the glaze or underglaze and the clay body are incompatible. The clay body shrinks more than the color, causing the color to peel or break away.
Shrinkage The reduction in size of a clay object as a result of firing.
Silk Sponge Used for decorating. It has short hairs on its surface and is soft when wet.
Slip The term used for clay in liquid form.
Slip Trailing The process of applying slip in an applicator bottle to flow on design for a raised effect.
Smoking Refers to the greying or discoloration of a glaze, caused by underfiring.
Soaking The process of holding a certain temperature in the kiln chamber for an extended period.
Soft Bisque Ware that has been fired to witness cone 06-05. (See Hard Bisque.)
Solvent A dissolving agent used in antiquing and to clean brushes used with oil-based colors.
Spattering A method of applying small flecks of color to ware, usually with a bristle brush.
Sponging Refers to the use of a sponge to apply colors directly to the surface of a piece.
Staggering Refers to the process of applying separate successive coats of glaze by fractions of an inch to prevent glazes from flowing together.
Stencil Refers to the process of using paper perforated with a design through which color can be brushed or sponged onto a surface.
Stilts are supports used to separate a glazed article from a shelf during firing. (See Furniture, Kiln)
Stippling A method of applying color by pouncing the tip of a brush loaded with color against the ware.
Terra-Cotta A natural low-fired clay. Terra-cotta is also a color name.
Thermal Shock Refers to extreme temperature change, usually caused by removing fired pieces too soon from the kiln.
Tint The process of lightly apply diluted colors over a base coat or coloring a product with another product.
Tipping Touching tip of loaded brush with other colors for muted shading or accenting.
Translucent Refers to transparent color, allowing color underneath to show.
Underglaze A ceramic color used under a glaze.
Utility Items Functional, rather than purely decorative items. Examples of utility items would be plates, vases, pitchers, bowls and planters.
Viscosity Refers to the rate of resistance to flow.
Vitreous The term used to describe an impervious or waterproof surface.
Wash The term for a color and water solution used for shading and antiquing.
Water-Based Antiquing Gels Nontoxic, nonfired, water-based colors for antiquing over all Duncan nonfired colors.
Wool Sponge An open textured sponge and soft when wet.