What is cloisonne? I am interested in enamel artefacts from China, and keep coming across this term used for what appear to be enamel objects - yet they sell for far higher prices. What is the story behind the art form? WHAT THE EXPERT SAYS: 'Cloisonne is a complex process, that includes enamelling,' explains Pola Antebi, director of Chinese ceramics and works of art at Christie's auction house. 'It's a unique method of decorating metal vessels, cast from either copper or bronze, with coloured glass paste enamel applied within copper wire enclosures. These enclosures, known as cloisons, were flat, thin strips bent and shaped to form various patterns that were then either glued or soldered to the surface of the vessel. Once the outline of the decorative design was complete, a variety of colourants were mixed with glass paste and applied with a brush in the small pools formed by the raised cloisons. 'The vessel would then be fired at a temperature of about 800 degrees Celsius to make the glass paste melt and harden. This process was repeated many times as the enamels shrank in the firing and did not completely fill each cloison. 'Once the surface was fully enamelled and void of any gaps, the surface was rubbed so that both enamel and wire enclosures created a smooth, even surface. 'Finally, the metal cloisons and rims were then gilded in gold leaf.' A POTTED HISTORY OF THIS GLASS-ON-METAL FORM The appearance of cloisonne differs greatly, according to the age of the piece and its usage, says Antebi. In China, glass inlay and glass paste inlay are known to have been used from the Shang dynasty (1600-1100 BC) onwards. Cloisonne enamel on bronze was a technique that reached a high level of refinement during the Emperor Xuande's reign (1426-1435) in the early Ming dynasty (1348-1644) and continued through to the 18th century. The most prolific era of production was during the Qianlong period (1736-1795) of the Qing dynasty (1645-1911) - when pieces were made to decorate the numerous imperial palaces and reception halls of the day. Vases of all forms are most commonly found on the market today; but there are also items for the scholar's desk as well as decorative objects, including animals of all sorts and, more rarely, even furniture. Many vessels imitate classical shapes and designs borrowed from Chinese antiquity. The most favoured decorative motifs were flowers, birds, landscapes and dragons. Cloisonne vessels were also commissioned for Buddhist ritual purposes or to be placed on temple altars. These would have been most commonly decorated with Buddhist symbols and lotus scrolls. Production continues today, and modern pieces are available in Chinese arts and crafts shops throughout China. NEW COLLECTOR TIPS: At the time they were made, cloisonne enamel vessels cost small fortunes, as the production was immensely labour intensive. However, notes Antebi, when compared to other decorative ware produced at the same time, such as ceramic or jade objects, cloisonne enamelled pieces are much more affordable, in part because there are fewer collectors at present. 'Prices vary based on the age of the piece and its rarity,' she adds, 'with 15th-century cloisonne vessels of imperial provenance having sold for millions and new ones for several hundred dollars. 'As always, it is best to purchase items through reputable dealers or auction houses.' Antebi recommends the Taipei National Palace Museum exhibition catalogue, Enamel Ware in the Ming and Ch'ing dynasties by Chen Hsia Sheng, available at Tai Yip bookstore at the Hong Kong Museum of Art.