China painting

China painting, or porcelain painting, is the decoration of glazed porcelain objects, such as plates, bowls, vases or statues. The body of the object may be hard-paste porcelain, developed in China in the 7th or 8th century, or soft-paste porcelain (often bone china), developed in 18th-century Europe. The broader term ceramic painting includes painted decoration on lead-glazed earthenware such as creamware or tin-glazed pottery such as maiolica or faience.

Typically the body is first fired in a kiln to convert it into a hard porous biscuit or bisque. Underglaze decoration may then be applied, followed by glaze, which is fired so it bonds to the body. The glazed porcelain may then be painted with overglaze decoration and fired again to bond the paint with the glaze. Most pieces use only one of underglaze or overglaze painting, the latter often being referred to as "enamelled". Decorations may be applied by brush or by stenciling, transfer printing and screen printing.

Porcelain painting was developed in China and later taken up in Korea and then Japan. Decorated Chinese porcelain from the 9th century has been found in the Middle East. Porcelain for trade with this region often has Islamic motifs. Trade with Europe began in the 16th century. By the early 18th century European manufacturers had discovered how to make porcelain. The Meissen porcelain factory in Saxony was followed by other factories in Germany, France, the UK and other European countries. Technology and styles evolved. The decoration of some hand-painted plates and vases from the 19th century resembles oil paintings. In the later part of the 19th century china painting became a respectable hobby for middle-class women in North America and Europe. More recently interest has revived in china painting as a fine art form.

The Chinese define porcelain as a type of pottery that is hard, compact and fine-grained, that cannot be scratched by a knife, and that resonates with a clear, musical note when hit. It need not be white or translucent. This porcelain is made from kaolin. The clay is mixed with petuntse, or more commonly feldspar and quartz. The glaze is prepared from petuntse mixed with liquid lime, with less lime in the higher-quality glazes. The lime gives the glaze a hint of green or blue, a brilliant surface and a sense of depth. Hard-paste porcelain is fired to temperatures of 1,260 to 1,300 °C (2,300 to 2,370 °F).

Soft-paste porcelain was invented in Europe. Soft-paste porcelain made in England from about 1745 used a white-firing clay with the addition of a glassy frit. The frit is a flux that causes the piece to vitrify when it is fired in a kiln. Soft-paste porcelain is fired to 1,000 to 1,100 °C (1,830 to 2,010 °F). The kiln must be raised to the precise temperature where the piece will vitrify, but no higher or the piece will sag and deform. Soft-paste porcelain is translucent and can be thinly potted. After firing it has similar appearance and properties to hard-paste porcelain.

The use of calcined animal bones in porcelain was suggested in Germany in 1689, but bone china was developed in England, with the first patent taken out in 1744. Bone china was perfected by Josiah Spode (1733–1797) of Stoke-upon-Trent in England. The basic formula is 50% calcined cattle bone, 25% Cornish stone and 25% china clay. The stone and clay are both derived from granite. The stone is a feldspathic flux that melts and reacts with the other ingredients. The resulting material is strong, white and translucent, and resonates when struck. It is fired at a medium temperature, up to 1,200 °C (2,190 °F), which gives it a much better body than soft-paste objects with a glassy frit. The firing temperature is lower than for hard-paste porcelain, so more metal oxides can retain their composition and bond to the surface. This gives a wider range of colors for decoration.

Earthenware pottery including tin-glazed pottery, Victorian majolica, Delftware and faience. Earthenware is opaque, with a relatively coarse texture, while porcelain is translucent, with a fine texture of minute crystals dispersed in a transparent glassy matrix. Industrial manufacturers of earthenware pottery biscuit-fire the body to the maturing range of the body, typically 1,100 to 1,160 °C (2,010 to 2,120 °F), then apply glaze and glaze-fire the piece at a lower temperature of about 1,060 to 1,080 °C (1,940 to 1,980 °F).

With stoneware and porcelain the body is usually biscuit fired to 950 to 1,000 °C (1,740 to 1,830 °F), and then glost or glaze fired to 1,220 to 1,300 °C (2,230 to 2,370 °F). Because the glost temperature is higher than the biscuit temperature, the glaze reacts with the body. The body also releases gases that bubble up through the glaze, affecting the appearance.