Chromatic characteristics of copper glaze as a function of copper oxide addition and sintering atmosphere

Abstract

Examined in this study were the effects of copper oxide (II) addition and sintering conditions on the chromatic characteristics of copper glaze. Oxidatively sintered samples exhibited the negative increase of CIEa∗ and the positive increase of CIEb∗ with the increase of CuO concentration, leading to Green and Green-Yellow coloration. On the other hand, CIEa∗ and CIEb∗ of reductively sintered samples were positively increased in direct proportion. The green color of oxidatively sintered samples was originated from the Cu2+ ions formed by the dissolution of CuO. The reductively sintered samples resulted in dull tone red color with low chroma. Such behavior seems to be influenced by the interplay of metal Cu aggregation, metal Cu globule, and Cu2O formed in the glaze layer through the redox interaction of CuO during the sintering process.