engobe

Slip is an aqueous suspension of a clay body, which is a mixture of clays and other minerals such as quartz, feldspar and mica. The slip placed onto a wet or leather-hard clay body surface by a variety of techniques including dipping, painting, piping or splashing. Principal techniques include slip painting, where the slip is treated like paint and used to create a design with brushes or other implements, and slip trailing, where the slip, usually rather thick, is dripped, piped or trailed onto the body, typically from some device like the piping bag used to decorate cakes. The French term for slip is barbotine, and this term may be used for both techniques, but usually from different periods. Often only pottery where the slip creates patterns or images will be described as slipware, as opposed to the many types where a plain slip is applied to the whole body, for example most fine wares in Ancient Roman pottery, such as African red slip ware (note: "slip ware" not "slipware"). Decorative slips may be a different colour than the underlying clay body or offer other decorative qualities. Selectively applying layers of colored slips can create the effect of a painted ceramic, such as in the black-figure or red-figure pottery styles of Ancient Greek pottery. Slip decoration is an ancient technique in Chinese pottery also, used to cover whole vessels over 4,000 years ago.

Many prehistoric and historic cultures used slip as the primary decorating material on their ware, especially in early periods. These include most prehistoric cultures of the Middle East and much later Islamic pottery, cultures in many areas of Africa, most pottery-making cultures in the Americas, early Japanese (and later Onta ware) and much Korean pottery. Much Mycenean ware, Ancient Greek pottery and Ancient Roman pottery used slip, as did pre-industrialized potters in many areas of Europe, including Great Britain, most notably Thomas Toft in the Staffordshire Potteries. Later potters mostly combined or replaced the use of slip with ceramic glazes and pigments offering a tougher finish and a wider range of colours. But a variety of slipware techniques were revived by various studio pottery movements from the 19th century on. In England Bernard Leach and in America Mary Louise McLaughlin were among the leaders of these revivals.

An example of slipware artifact is the Harvest jug.

• Illustration — Simple slip-trailing in thick blobs, Roman Egypt, 0-200 AD • Illustration — Bowl with strutting bird, Sultanabad ware, Iran, Ilkhanid period, first half of 14th century, earthenware with gray engobe and underglaze painting in blue, black, white slip • Illustration — Korean punch'ong ware pear-shaped wine bottle, Choson dynasty, second half of 15th century, stoneware with glaze and white slip decoration • Illustration — English Slipware mug, ca. 1740 • Illustration — Ashiwi slip-painted jar, She-we-na Zuni Pueblo, 1700-1750 • Illustration — Sugar bowl with combed, slip-marbled decoration, China, c. 1795, porcelain • Illustration — Tile, Hopi Pueblo, late 19th-early 20th century • Illustration — Modern slip-trailed bowl by Takeshi Yasuda • Illustration — A fine Werra ware slip-decorated dish dated 1590. (Germany)