In the West, firing process inspired by traditional Japanese raku firing. In American raku, work is removed from kiln at bright red heat and subjected to post firing smoking by placing in containers of combustible materials, which blackens raw clay and craze cracks in glaze.

Profile of the firing of a kiln, including speed, duration, soaking periods, etc. of both the heating and cooling cycle, as in firing ramp and cooling ramp.

Glazing leather-hard or bone-dry wares for single-firing.

During initial cooling, the formation of microcrystalline or macro crystalline structure in the glaze surface

Pb₃O₄ Former source of lead for glazes. Highly toxic in absorption, inhalation, and ingestion. Remove from studio and dispose of in a responsible fashion.

Brick-red earthenware clay, produced by Cedar Heights Clay Company.

In ancient Greek ceramics, Classical stage of vase painting, featuring figures in red against black background, with highlights painted in black and white.

To induce reduction.

Material such as silicon carbide used in clay or glaze to create localized reducing conditions in an oxidation firing.

Chemical reaction in which oxygen atoms are removed from a compound.

In a fuel kiln, maintaining slight reduction atmosphere during cooling cycle, from maturing temperature down to approximately 1400° F, in order to minimize reoxidation of clay and/or glazes. See reoxidation.

In fuel-burning kilns, firing atmosphere with insufficient oxygen to completely combust fuel, introducing abundance of unoxidized carbon and hydrogen, which extract oxygen molecules from surface of wares, altering appearance of clay and glaze. See climbing reduction.

Any materials highly resistant to the effects of heat. In kiln construction, high-temperature insulating materials, such as firebrick, ceramic fiber, etc. In clay and glaze chemistry, the neutrals or stabilizers that are resistant to melting and that combine with the fluxes (bases) and glass-formers (acids). Primary refractory material in ceramics is alumina, most often introduced in the form of clay (aluminum silicate).

Capable of withstanding very high temperatures.

In plaster slip-casting molds, small rounded depressions carved in each parting face of a mold segment, so that when adjacent segments are cast a corresponding bump will form. In use, the keys allow the mold segments to be aligned and assembled securely after the original prototype is removed. 

In a reduction firing, oxidation that occurs after fuel is shut off at end of firing.

In a wood kiln, the surface effects created by fly-ash settling upon the wares. Effect is maximized by turbulence in firebox, considerable draft through kiln, and/or active stirring of the coal bed. In short wood firings ash doesn't have time to melt, and leaves a rough, crusty surface.

In a well-used salt/soda kiln, the light salt/soda effect that may be obtained by firing wares in the kiln without introducing any additional salt or soda, due to the revolatization of salt/soda from the walls of the kiln.

Material used in glazing and decorating that can be applied to surface to prevent adhesion of slip or glaze.

Variable electric switch often found on forced-air burners to control blower speed. Small inexpensive rheostats used on most power burners are imprecise, and adjustments should always be made on basis of flame at burner tip, preferably with an air- shutter on the blower-intake for fine adjustments.

Wide, flat handheld tool used to shape, smooth, and/or scrape clay surfaces; usually wood, rubber, plastic, or metal, either rigid or flexible, with straight, curved, or profiled edge.

Beveled edge obtained by rolling the outer edge of the foot of a soft leather-hard pot at an angle against a hard flat surface.

Kiln arch that forms a perfect half circle, with the arch beginning and ending on a horizontal surface, using no skew bricks.

Small stamp wheel with raised pattern around the rim, which when rolled along a plastic clay surface leaves a band of relief pattern. Usually formed with damp or dry clay and bisque-fired.

Titanium ore, used as source of titanium dioxide, contains iron, other trace minerals gives tan color, promotes crystallization giving mottled multicolor effects in some HT glazes, or in over glaze stain (very refractory, use sparingly). Gives rich mottled medium blue in some HT glazes. Dark Rutile contains higher percentage of iron.