Cobalt

The colourant

Cobalt is the source of almost all the blues in Jingdezhen porcelain. Fired at high temperature, a small amount produces a stable blue that, depending on the ore, its preparation, the glaze and the firing, ranges from pale greyish tones to a deep violet-blue. The prepared pigment is traditionally called 青料 (qīngliào).

Ways of using cobalt

The same colourant appears in very different forms. In blue-and-white, cobalt is painted onto the body beneath a clear glaze. In sacrificial-blue glaze, the cobalt is carried by the glaze itself, so that the whole surface reads as one deep tone. In Sǎlán, powdered cobalt is blown onto the body before glazing. And in some glazes, such as the Jingdezhen sky-blue glaze, a small addition helps bring out a blue cast.

Historical sources

The cobalt used at Jingdezhen changed over the centuries. Blue Fir records the historical sources separately: Sumaliqing, associated with Yuan and early Ming blue-and-white; domestic Ming cobalt; refined Qing cobalt; and modern industrial cobalt.

Blue Fir objects

An object is linked to this page only where the maker’s description refers to cobalt. Other blue glazes and techniques are connected here through their own records.