ALKALINE GLAZES
Glazes containing alkaline oxides as fluxes. See fluxes.
ASHES
Non-combustible remains of animal and vegetable matter used in pottery bodies and glazes as fluxes See fluxes.
ATMOSPHERE
Air surrounding pots during making and firing. See reduction.
BISCUIT
Pottery fired once at around 980°C.
BISQUE
Industrial method of firing pottery a first time at a higher temperature than for the glaze fire.
BALL CLAY
Highly plastic clay of the secondary type, containing few impurities. See sedimentary clays.
BASALT WARE
Black unglazed stoneware developed by Josiah Wedgwood.
BODY
Material from which pottery is made. In porcelain often referred as paste.
BONE CHINA
European porcelain containing bone ash, petuntse and kaolin.
BURNISHING
Polishing unfired pottery with a hard tool to render it waterproof after firing.
CELADON
Feldsphatic glaze ranging in colour from grey-green to brown-green, stained with iron oxide and reduction fired. See reduction.
CERAMICS
Clay products made permanent by heat.
CHAMOTTE
French term for grog. Finely ground refractory clay used to give mechanical strength to plastic clay.
CHINA
Term used to describe English porcelain and white earthenware.
CHINA CLAY
See kaolin.
CHINOISERIE
European eighteenth century decorating fashion inspired by Chinese ornaments.
COBALT
Mineral usually used in the form of oxide, carbonate or aluminates to produce blue colours on pottery.
COILING
Making of a pot with clay coils applied one on the top of the other.
COPPER
Metallic element used in the form of oxide or carbonate to produce turquoises in alkaline and greens in lead glazes. In reduction firings produces a bright red.See Sang de Boeuf.
CHROME
Metallic element used in the form of an oxide to produce green and yellow colours.
CREAMWARE
Cream coloured earthenware covered with a lead glazed developed by Josiah Wedgwood in 1760.
CRACKLE
Glaze covered with a network of thin cracks, due to a different shrinkage rate between clay and glaze.
DELFTWARE
Tin glazed earthenware with cobalt blue decoration originally made in Delft, Holland.
EARTHENWARE
Porous pottery body fired at below 1100°C
ENAMEL
Paint made from powdered glass and metallic oxides. It is applied over the fired glaze mixed with oil or resin, and fused into place at around 700°C.
ENGOBE
See slip.
FAYENCE
French word for low temperature ware, mostly white firing bisquit.
FELDSPAR
Group of crystalline minerals used as fluxes in bodies and glazes. A main ingredient in the production of porcelain.
FAMILLE ROSE, FAMILLE VERTE
Chinese porcelain decorated with predominantly pink resp green enamels.
FIRING
When clay is turned into ceramic, usually in a kiln.
FLAMBé
Reduction fired copper glaze streaked with blue or black. First developed by the Chinese in the Sung Dynasty (960-1280).
FLUXES
Oxides or organic matter used in clays and glazes to lower the melting point of silica (powdered glass). See ashes and alkaline glazes.
FRIT
Part of a glaze that has been melted and reground. A way to render unsoluble and harmless alkali and lead oxide.
GILDING
Covering an object with a thin layer of gold. In pottery gold powder is mixed with a resin and applied with a brush. By firing in the kiln at ~650°C the glaze begins slightly to melt and resin burns leaving the gold on the surface of the pot.
GLAZE
Glassy coating applied to ceramics to give it waterproof qualities.
GRAND FEU
French term for high temperature glazing.
HARD PASTE
True porcelain made with kaolin and petuntse and vitrified at up to 1400°C.
HAND BUILDING
Making of a pot totally by hand. Techniques include coiling, slab building and pinching.
IRON
Metallic element used in glazes in the form of an oxide to produce brown and yellow colours.
JIGGER AND JOLLEYNG
Casting of pots in hollow moulds mounted on a spinning wheel.
KAOLIN
Fine white feldspathic clay from the primary type.See residual clays.
LUSTREWARE
Pottery decorated with metallic paints and fired in reduction atmosphere.
MAIOLICA
Italian tin-glazed earthenware painted with overglaze colours.
MAJOLICA
Moulded earthenware decorated with bright coloured lead glazes, popular in Victorian England.
MANGANESE
Metallic element used to produce purple and brown colours.
OVERGLAZE
Decoration applied over the glaze.
PETIT FEU
French name for low temperature or enamel colours.
PETUNTSE
Feldsphatic rock essential in the production of porcelain.
PORCELAIN
Hard translucent and vitrified pottery fired at up to 1400°C.
POTTERY
Term used to describe all types of ceramics.
PRESS-MOULDING
To cast a vessel into a hollow mould.
RAKU
Low temperature lead glazed, reduction fired Japanese pottery.
REDUCTION
Firing with reduced oxygen in the kiln. The flames suck oxygen from the glaze, changing its composition.
RESIDUAL CLAYS
Clays from the primary type, which have remained in their place of origin, and have been decomposed from their rock state by the action of underground water. See kaolin.
SALT GLAZING
Pitted stoneware glaze obtained by throwing salt into the firing chamber.
SANG DE BOEUF
French for ox blood. See copper and flambé.
SEDIMENTARY CLAYS
Clays of the secondary type, which have been moved from their original position, by the action of the elements. See ball clay.
SGRAFFITO
Decoration scratched through a layer of slip on a pot's surface, showing the colour of the clay underneath.
SLIP
Liquid clay.
SLIPWARE
Earthenware decorated with coloured slips.
SLIP CASTING
Casting of pots in hollow moulds using liquid clay.
SLAB BUILDING
Making of a pot with slabs of plastic clay.
SOFT PASTE
Eighteenth century first attempts at recreating hard paste porcelain produced in France and England. It fired up to 1150°C, and was made with silica (powdered glass) instead of petuntse.
SPRIGGING
Moulded relief decoration.
SPONGEWARE
Pottery decorated with a sponge impregnated in colour.
SPRAY BOOTH
A booth in which glazes are sprayed onto pots, with a spray gun and a compressor.
STONEWARE
High temperature pottery body. Fires at up to 1280°C, when vitrification occurs.
TIN GLAZE
Opaque, white, low temperature glaze made with tin oxide.
TRANSFER PRINTS
Printed decoration transferred from a copperplate engraving, via transfer paper to pottery.
TRANSLUCENCY
The propriety of porcelain to let light shine through, when thin walled.
VITRIFICATION
When a pottery body stops being porous. See stoneware and porcelain.