Copper oxide (CuO and Cu₂O) is a versatile pigment in ceramics, known for its ability to produce a wide range of colors, from bright greens and turquoises to deep reds and browns. The resulting colors depend on the concentration of the oxide, the glaze formula and kiln conditions (oxidation or reduction).
In oxidizing atmospheres, copper oxide generally produces green and bluish tones. In reducing atmospheres, it is chemically transformed to produce bright reds, such as the famous copper red found in many traditional East Asian ceramics. It can also generate metallic or iridescent hues when combined with other oxides or reactive glazes, where its unpredictable behavior in the kiln creates unique textures and patterns. This makes it a favorite of ceramists seeking to explore experimental decorative effects.
Interesting Fact
Copper oxide has been used in ceramics since ancient times. The ancient Egyptians used it to decorate ceramics and glass, and its use spread to Islamic and European ceramics during the Renaissance.
Helpful Tip
Start with low concentrations (1%-3%) to avoid the color becoming too saturated or the glaze becoming unstable. Wear gloves and a mask, as copper oxide dust can be toxic. Test to determine how it responds in different firing atmospheres and with various glaze combinations.
