ART 130 Ceramics Vocab

Bisque

Clay that has gone through its first firing to harden while remaining porous to accept glaze (low firing cone 06-04)

Greenware

Unfired clay in any of its states of dryness or wetness.

Leather Hard

Unfired clay that has stiffened up enough to be workable but is not completely bone dry.

Bone Dry

Clay that is completely dry but has not yet been fired.

Slip

Watered-down soupy clay used to attach pieces of clay together. (leather hard to leather hard or wet clay to leather hard)

Engobe (Underglaze)

Slip containing stains or oxides used to paint on the surface of leather hard clay.

High Firing

A ceramic firing that reaches cone 7 or higher, such as cone 10.

Low Firing

A ceramic firing that ranges between cone 06 (or lower) and cone 1.

Reduction Firing

A kiln atmosphere lacking sufficient oxygen, allowing certain oxides in clay and glazes to change color.

Majolica

A low-temperature decorating technique where oxides or stains are painted on a raw glaze prior to firing.

Oxides

Heavy metal materials used as colorants in glazes, such as copper (GBR), iron (R/black), tin or titanium (white/pink)

Pyrometric Cones (Low Range)

Cones 010, 09, 08, 07, 06, 05, 04, 03, 02, 01, and 1.

Pyrometric Cones (Medium Range)

Cones 1, 2, 3, 4, 5, and 6.

Pyrometric Cones (High Range)

Cones 7, 8, 9, and 10.

Low temp firing clays & glaze

• Vitrify (become glass and non-porous) before cone 1

• Fired in oxidation, which is when the atmosphere inside the kiln has sufficient oxygen to burn fuel efficiently

• Glazes brighter, more colorful and more reliable

• The clay body less durable

High temp firing clays & glaze

• Vitrify at higher temperature-cones 7-10

• Glazes darker/earthier, considered in terms of textures > color

• Glazes generally fired in reduction

• Glazes generally greater variation than low fire and offer a wider palette