Flambé, Transmutation glaze, Jingdezhen Jun or in its monochrome version - Jun red was another Qing innovation which came about through the Yongzheng emperors interest in various aspects of antiquity. In 1727 the Jingdezhen potters were commissioned by the court in Beijing to re-create the famous classical Jun wares of the Song period.
The potters at the official workshops were challenged to experiment with new techniques and styles. They came up with shapes, clearly influenced by archaic bronze vessels and a new ware on a porcelain body using three distinctly different glazes, one for the blue inside, one for the red outside and a third for the brownish green applied within the foot-rims. The Iridescent blue, purple, or brown splashes and streaks characteristic of this glaze are described as yao bian, or "transmutation glaze" and resulting from transmutation of colloidal copper, iron, or other metallic materials into suffusions breaking up the glaze surface.
During the Qing dynasty and onwards this Flambé glaze was made in red and with blue and other combinations on a white porcelain body. From the mid-18th century and onwards the red one of those glazes became the standardized Jingdezhen Jun red. A typical feature of these later glazes is they being very fluid in high temperatures so that their bases most often needs grinding after firing, to remove excess glaze. The term is still used by the Jingdezhen potters to describe their standard shiny red monochrome porcelain glazes.
Text courtesy of Mike Vermeer, 2014
See also: Jun