Porcelain

I

Introduction

Porcelain, a ceramic body comprising white china clay or kaolin (aluminium silicate) and feldspathic rock (see Feldspar) or petunse (aluminium and potassium silicate) that, fired in a kiln at between 1280° and 1300° C (2336°–2372° F), vitrifies to form a white, resonant, and translucent material of greater density and hardness than the pottery bodies, earthenware and stoneware. It was first made by the Chinese in the 7th or 8th century ad but not in Europe until the 18th century.

Soft-paste porcelain (as distinct from hard-paste, or true, porcelain) was the result of European attempts to imitate the Chinese porcelain body with mixtures of white clay and frit (ground glass), fired at lower temperatures. Bone china, produced by adding calcined bones, is harder than soft paste, but not as dense as true porcelain. Perfected in England at the end of the 18th century, it became the standard English porcelain body.

These bodies, or pastes, could be shaped by pressing the soft clay into moulds, often in segments, and then joining the dried-out, contracted, pieces with a liquid clay mixture or slip (press-moulding); by pouring slip into absorbent moulds which soaked up the water, leaving a similarly dried-out, contracted shape (slip-casting); or by working the clay on a potter's wheel (throwing).

Unglazed, once-fired porcelain is known as biscuit or bisque ware; more often, feldspathic glaze was applied to the porcelain body before its first firing, to form a glassy, non-porous surface. Underglaze painting could be applied at the biscuit stage, but before 1800 blue (from cobalt) and purple (from manganese) were the only colours that withstood the high temperatures of porcelain glaze firing. On-glaze, or overglaze, decoration with enamel colours, fixed by a subsequent firing at about 750° C (1380° F), gave the painter greater possibilities. Soft-paste porcelains were usually covered in lead glazes which required a second firing, while the use of on-glaze enamel pigments demanded a third. This made them very expensive to produce.

Other forms of porcelain decoration included incising and moulding patterns in the raw clay surface; undercutting and piercing, and applying separately moulded motifs to the unglazed surface (sprigging). Transfer-printing, allowing multiples of a design to be produced, was an English invention of the 1750s and was of vital importance for the development of the ceramics industry. During the 19th century technical exploration allied to exuberant taste resulted in new porcelain materials like parian ware and Belleek, and decorative processes such as pâte sur pâte, acid gilding, and the intaglio moulded pictures known as lithophanes.

II

Oriental Porcelain

A

China

The emergence of true porcelain in China, nearly 1,000 years before its secrets were unlocked in the West, was a gradual process, built upon a long-perfected tradition of pottery-making and greatly helped by the availability of the ideal natural ingredients. Porcellanous wares are known from the Tang period (618-906), and during the Song period (960-1279) elegantly shaped porcelains with incised decoration and glazes varying from ivory and the palest greens and blues to reddish-brown and even black were being produced. The greenish celadon wares were the most important of these.

Among the earliest exports of porcelain were the bluish glazed Qingpai wares and the lustrous white porcelains of Te Hua, known as blanc de chine. However, the outstandingly influential products of the Chinese potters were the underglaze blue decorated porcelains that appeared in the early 14th century and burgeoned during the Ming period (1368-1644). These high-quality low-priced wares were produced in vast quantities, to be received voraciously in the West.

During this period the Chinese also developed a range of techniques for decorating porcelain with overglaze colours, with or without underglaze blue; sometimes several techniques were combined, while the successful exploration of coloured glazes resulted in some of the most distinguished pots.

The decoration on the blue-and-white and polychrome wares, which was becoming more important than the shapes of the pots themselves, included plants such as peony, prunus, chrysanthemum, pine, and lotus; birds and butterflies, dragons, deer, and other animals of mythological or religious significance. Figurative scenes were derived from old romances or contemporary picture books, and a wide vocabulary of symbolic patterns and motifs was used for all-over designs or for borders and panels.

During the reigns of the emperors Kangxi (1661-1722) and Yongzheng (1722-1735) the enormous output of blue-and-white wares continued, while polychrome wares in a fresh range of palettes known in the West as famille verte (in which green predominated), famille jaune (yellow), and famille rose (pink) were produced both for home consumption and export. Much of the porcelain produced during the 18th century, particularly during the reign of Qialong (1736-1796), consisted of fine-quality reproductions of earlier styles in the Chinese tradition of reverence for the past.

Increasing Chinese intercourse with Europe during the 17th and 18th centuries resulted in the systematic production of porcelain made in China for export to the West. These export porcelains were decorated with colourful scenes derived from European prints, or with the armorial bearings of the families who commissioned them.

B

Korea

While Chinese influence dominated early ceramic development in Korea, distinctive styles both of potting and glazing were apparent from the 12th century onwards. One type was a form of celadon ware in which black and white slips were inlaid into incised decoration in the pottery body before being covered in glaze; another was painted in brown under the celadon glaze. The Koreans introduced underglaze painted decoration in copper-red during the 13th century and produced fine undecorated white porcelains from the 15th. Underglaze blue porcelain was not produced in quantity until the 18th century.

C

Annam

The area of South East Asia which is now North Vietnam played a significant part in porcelain production from the 14th to the 17th centuries, thanks to abundant supplies of feldspar and kaolin near Hanoi. The Annamese were using cobalt as early as the Chinese (14th century) and fine blue-and-white decorated porcelains were produced in Tho-ha and Bat Trang. The earlier wares closely imitated Chinese, but distinctive characteristics of decoration as well as potting technique had emerged by the 15th century when the best Annamese porcelains were produced. Among the distinctive Annamese products were circular covered boxes, and water droppers in the form of animals.