Page 68 - The colours of each piece: production and consumption of Chinese enamelled porcelain, c.1728-c.1780

CHAPTER 2 The Production of Enamelled Porcelain and Knowledge Transfer

the term ‘under-glaze’ means that the decorative pattern is made on the raw clay body

surface, which is then covered with a clear glaze, and subsequently fired at a high

temperature in one session, a process which requires the pigment to withstand high

temperatures in the kiln, and turn into an effective, colourful glaze. Iron, cobalt and

4
copper are among the main ingredients that can withstand such high temperatures. It
should be mentioned that underglaze porcelain only requires one firing. In contrast,

with under-glazed decoration, over-glaze porcelain has been decorated with

decorations over the glaze, as the name states. This technique creates more colours

than under-glaze painting; it involves the use of several colours on the top of the glaze.

Porcelain with over-glaze decorations requires at least two firings, because the first

firing was at a high temperature for the initial glaze and the second firing was at a

much lower temperature for the over-glaze enamels.

The technique of applying enamels over the glaze can be dated back to the

thirteenth century in northern China. Some small stoneware dishes have been found

in the Cizhou kilns, Hebei province, northern China, decorated with green and red,

5
yellow enamels, all fired at lower temperatures. Despite the decorative potential of
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the technique, only a few of these early examples of good quality have been found.

By the end of the fifteenth century, Jingdezhen potters were able to use six enamel

colours: red, yellow, green, turquoise, aubergine, and black. The combined use of the

full range of over-glaze enamels effects led to a new style, known as wucai (五彩,

4 For a general introduction of Chinese under-glaze porcelain, see Margaret Medley, The Chinese
Potter: A Practical History of Chinese Ceramics (third edition, Oxford: Phaidon, 1989), pp.176-
191.
5 For an analyses of Cizhou over-glaze enamels, see Nigel Wood, Chinese Glazes: Their Origins,
Chemistry and Recreation (A&C Black: London, University of Pennsylvania Press: Philadelphia,
1999), pp.230-235.
6 Ibid.
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