underglaze iron en

Refers to a ceramic decoration technique in which iron oxide-based pigment is diluted in water and typically applied with a brush onto a vessel'€™s surface before glazing. When fired in reduction, the decoration appears black or brown. In Korea, the technique was applied to Goryeo cheongja (Goryeo celadon) and later to buncheong sagi (buncheong ware) and white porcelain. It became especially widespread in the 17th century as an alternative to cobalt-blue underglaze painting. When the pigment is applied over the entire surface it is called "€œcheolchae" (iron coloring), but when only motifs are painted it is called "€œcheolhwa" (iron painting).