Glossary of ceramics

Bisque or bisque fired (Biscuit fired) – A piece that has been fired to the first lower temperature firing usually in preparation for glazing.

Burnish – to rub the surface of clay with a smooth object like a spoon or pebble to seal the surface before firing for the first time.

Ceramic – what clay transforms into after firing in the kiln.

Coiling – building in clay using long coils of rolled out clay.

Earthenware – lower firing range 1040C- 1160C

Figurative – easily recognisable as something.

Firing – heating clay in the kiln to transform it into ceramic.

Glaze – the coating that is placed on the surface of ceramic to seal and decorate it.

Greenware – Pieces made of clay before they are fired in the kiln for the first time.

Hand building – all the techniques to make in clay that don’t use any large pieces of equipment or machinery including pinch pots, slab building and coiling.

Kiln – purpose built equipment like an oven that can reach extremely hot temperatures needed to fire ceramics. Can be electric, gas or wood fired.

Mocha – a decorative slip technique that uses ph differences to create tiny fingers of colour in slips.

Oxides – decorative mediums/pigments made from metal oxides, carbonates etc usually in powder form.

Oxide wash – an application of oxide to the surface of a bisque fired piece that is then washed off to leave the oxide in the deeper marks highlighting texture.

Pinch pots – creating pieces from clay by pinching out from the centre of a round shape.

Porcelain – smooth, white, high firing clay with translucent qualities.

Raku – Japanese firing technique that uses a gas kiln that means pieces are removed from the kiln at the top temperature and then treated in different ways depending on the decoration wanted.

Slab building – building in clay using flat slabs.

Slip – watered-down clay that is used to stick clay together.

Slips (decorating or coloured) – coloured liquid clay used for decorating pieces made of clay.

Smoke fire – putting bisque fired pieces in a container and lighting a fire around them so that the piece absorb some of the carbon from the smoke to produce a decorative finish.

Stoneware – medium firing range 1180C – 1260C

Terra-siglata – very fine slip made from just the finest particles of clay that don’t settle in water used for burnishing to an extremely smooth surface.

Throwing – creating pieces in clay on a wheel.

Underglaze – pigments in a liquid or pencil medium that can be used to apply colour to greenware or bisque pieces that has a transparent glaze placed over the top to seal them.

Different types of glazes – celedon (usually a semi-transparent fluid glaze), shino (opaque tonal glazes), float (fluid glazes with a base colour and float layer in a second colour), tenmoku (dark browns), crackle (deliberately crazed glazes), lava/crater (glazes that create a highly textured surface with craters), lichen and crawl (glazes that separate into small pieces showing the clay between), crystal (glazes that have crystalline structures formed during firing).

Glaze properties – transparent (clear glaze that shows what’s beneath), semi-transparent (clear glaze with some colour in it), opaque (solid colour that covers what’s beneath), glossy (shiny glaze surface), satin or satin matt (slight sheen on the glaze surface), matt (no shine at all on the glaze surface).