underglaze copper-red en

Refers to a ceramic decoration technique in which copper oxide pigment is diluted in water and painted onto the surface of a vessel before glazing and firing. In reduction firing it appears red, while in oxidation it turns green. Achieving a stable color can be difficult due to the high volatility of the pigment, requiring considerable time and skill. In Korea, it was used on some celadon during the late Goryeo Dynasty and on white porcelain from the 18th century onward, during the Joseon Dynasty.