The two basic atmospheres, oxidation and reduction, affect the color of the final piece. Glaze A coating of material applied to ceramics before firing that forms a glass-like surface. Glazes can be colored, opaque, translucent or matte. Kiln The furnace in which ceramics are fired. Kilns can be electric, natural gas, wood, coal, fuel oil or propane.
Some potters introduce chemicals into the kiln to influence the effects of the firing.
Famed ceramist Beatrice Wood achieved a lustre effect by throwing moth balls into the kiln. A firing atmosphere with ample oxygen. An electric kiln always gives an oxidizing fire. In a wood or gas firing, the mixture of fuel and air is perfectly adjusted to give a clean burn. Acoma whiteware is fired in oxidation.