Glossary of Common Terms for Ceramics Painters

- the process of applying paints to an item using a compressed-air spray gun.

Antiquing - the process of applying a paint and then wiping it off, leaving varying amounts of color on the design or item.

Banding Wheel - a flat and stable surface on a revolving base used to rotate an item while painting.

Bisque - (sometimes spelled "bisq") - a greenware item (see Greenware below) that has been fired to a degree of hardness which removes all moisture from the piece. This creates a stable substance, less likely than greenware to break or chip, and providing an adequate surface to apply glazes and paints.

Casting- the process of filling a mold with slip (liquefied clay), allowing it to sit for a carefully monitored length of time, and then pouring out the liquid. A layer of slip will have dried to "leather" consistencey and conformed to the inner contours of the mold. After additional drying time, the parts of the mold are separated and the dry "greenware" is removed and touched up by hand before being bisque fired.

Ceramics - in a general sense, the art of creating items out of clay. This includes earthenware, stoneware, porcelan and bone china.

Ceramist - any person dabbling in the practice of creating ceramic items.

China Paint - a concentrated paint/color pigment applied to fired, glazed china or porcelain bisque which is then re-fired to harden and fuse to the item.

Cleaning - the process of removing seams and flaws from greenware.

Cone - pyrometric devices made of specially formulated clay designed to melt at specific temperatures, used to monitor the firing temperatures of kilns. The coolest cone number is 022 and the hottest is 42. In these days of digital controls, fewer people actually use cones, but they are still a useful way of expressing kiln pemperatures. Here is our own chart of cone numbers and kiln temperatures.

Crawling - a flaw in a fired glaze where the glaze pulls away from the surface of the item leaving an area of bare bisque.

Crazing - a flaw where glazes have a web-like cracking in the surface of the finished piece. Prevalent in vintage ware, though a continuing problem with modern ceramists.

Decals - colored painted designs on a thin film like base which are applied to fired glaze surfaces and then re-fired to fuse to the surface of the item. The filmy base is fired away just leaving the design.

Deflocculant - a chemical such as sodium silicate or sodium carbonate which reduces the amount of water needed to make slip fluid - consequently reducing shrinkage after it is applied to the clay.

Drybrushing - The process of using a stiff bristled dry brush and small amounts of paint to gradually add color to a base-coated item through dragging the brush cross-wise over the raised details of the design, or by a pouncing to create a softer cloth-like finish.

Dryfoot - the practice of leaving the bottom of a ceramic piece unglazed so that it can be fired standing on the kiln shelf without being stilted. Some molds are specifically designed to produce ware that can be dryfooted. Stoneware and porcelain are always dry footed.

Earthenware - a low-fire blend of clay, usually porous, used worldwide for domestic ware.

Engobe - a colored decorating slip, often opaque. Concentrated color is added to liquid slip and then applied to greenware before firing. Many underglazes are Engobes.

Glaze - liquid composed primarily of silica which creates a glassy coating that is fused onto the surface of the clay when fired. Glazes may be matte or glossy, depending on their chemical makeup.

Greenware - any unfired clay object.

High-Fire - the firing of a clay body to the range of cone 2 up to cone 13. Ware fired at cone 2 and up is usually referred to as Stoneware. Here is our own chart of cone numbers and kiln temperatures.

Kiln - the oven used to fire or bake clay or glass items.

Kiln sitter - the part of a kiln that holds the firing cones and gauges the temperature then automatically shuts off the kil.

Lace Draping - the process of dipping cotton lace into slip and applying it to an unfired item and then firing it. The lace burns away, leaving the delicate clay design.

Low-fire - the firing of a clay body to the range between cone 015 and cone 1. Ware fired at low temperatures is usually referred to as Earthenware.

Majolica - a glaze technique of applying an opaque satin/matte glaze to bisque, then colors are painted on this and fired to fuse the two together and create a bright, colorful surface.

Maturation Point - the firing point at which a clay body reaches its maximum hardness and non-porosity.

Mold - a plaster form which is used to shape and model clay.

Opaque - solid color, not transparent in any way. (You cannot see through an opaque color!.

Open Pour Mold - a one piece mold that can be used for casting slip or pressing clay into it.

Overglaze - colored paint-like surface decorations which are applied on top of a previously fired glazed piece which is then fired again at very low temperatures. Most common are gold, mother of pearl, decals and china paint.

Peephole - the hole/s on the side of a kiln used to view the inside during firing and to allow the exchange of oxygen and gasses during the firing process.

Pinholes - a small pore in a glaze surface which is caused by escaping gases.

Polished Underglaze - the process of rubbing damp underglazes to a sheen prior to firing them.

Porcelain - a blend of clay, usually white, which is fired to a high temperature at which the clay body vitrifies and becomes translucent.

Pour gate - the opening of a plaster ceramic mold where the slip is added.

Press mold - a mold used by pressing clay into it.

Reverse Dry-brushing - the same as dry-brushing except color is built from a dark base and each layer is increasingly lighter. The lightest color is the last, top most layer.

Semi-Transparent - the ability to see through color slightly with some distortion. In the case of glazes, color deepens in crevices and details of item and is lighter on the high points.

Semi-Opaque - Dense color that has a very slight translucenc.

Slip - liquefied clay used for casting ceramic molds. A finely sieved mixture of clay and water, either white or colored, which can be applied to clay surfaces in one or more layers.

Slip Trailing - the method of decorating ware by squeezing thickened slip from a bottle or nozzle onto the surface of the pottery to create raised lines.

Spare - the clay waste which is trimmed from the pour gate of a mold before the greenware is removed from the mold.

Spray fix - a clear spray used to give a protective finish to stained, non-fired items.

Stain - most commonly referring to non-fired painting techniques.

Stoneware - a blend of clays, usually brownish in color, which is characteristically fired to a high temperature at which the clay body becomes vitrified and non-porous, but not translucent.

Terra cotta - a type of clay whose name translates as 'baked earth' ranging in color from yellow to orange to red.

Transparent - clear or color you can see through. Transparent glazes generally 'settle' into detailed areas, making them slightly darker and bringing the detail to view.

Underglazes - a liquid containing a clay or chemical base with colored agents which are used under a glaze. Most commonly indicates colors used to decorate greenware and bisque before a protective clear glaze is applied.

Viscosity/viscous - the fluidity of ceramic slip.

Vitrification - the point at which a clay body or glaze reaches a glassy, dense, hard and non-absorbent condition.

Wax resist - a wax emulsion especially created to repel underglazes and glazes applied over them. The wax is burned off during firing, revealing the designs protected from other paints applied around them.

Wet-brushing - similar to dry brushing only using slightly larger amounts of paint, enhancing the color at a faster rate resulting in filling in the design details somewhat more than the drybrushing technique.

Wetware - any clay item that is freshly removed from a casting mold or still wet.