Yongxing Li and Chen Shen. Adaptation and Innovation: The Imperial Cloisonné Collection
Enamel, or falang, is a paste-like material made by fusing powdered glass to a substrate: compounds of borate and silicates are mixed with a series of chemicals and metallic oxides and then fired at temperatures of 700–900°C. Colourants containing cobalt make a rich blue colour, while manganese and uranium yield purple and orange when they are oxidized. Iron produces colours ranging from light green to brown, and tin makes an opaque white; copper produces a green hue in oxidation and a blue to red in reduction (Barry Till and Paula Swart, Antique Chinese Cloisonné, Victoria, BC, 1983). The term falang qi, or enamelled ware, usually refers to metal vessels or objects with enamelled decoration, although glass and ceramic may also be used.