What is green glaze washing?

Washing green glaze is a famous tradition of porcelain and glass in China. Also known as "celadon glaze". The color of green glaze is not pure green. The ancients often referred to cyan, green and blue as "cyan".

China ancient green glazes used iron as the main coloring element and calcium oxide as the main fluxing agent. The colored glazes with iron oxide were burnt into yellow in the oxidation flame and turned into cyan after reducing flame. On the other hand, the content of iron oxide in glaze has a great relationship with the color of glaze. For example, the celadon oil of Guyue kiln and Wuzhou kiln contains iron, and the glaze color is dark, showing bean blue or wormwood color; The iron oxide content of European kiln celadon glaze in Tang Dynasty is that the glaze is light blue; Deqing kiln uses purple mud with high iron content to prepare black glaze, so that the iron content in the glaze is as high as possible, so the color is black as paint.