Copperglazed

Copperglazed refers to ceramic ware finished with a glaze that contains copper compounds. The copper in the glaze interacts with the glaze matrix and the firing atmosphere to produce distinctive color effects that can range from greens to reds.

Color outcomes depend on the chemical form of copper (such as copper oxide or copper carbonate), the glaze base, fluxes, and firing conditions. Oxidizing atmospheres commonly yield green or turquoise hues, including celadon-like tones, while reducing atmospheres can produce red or brownish copper-red colors. In some systems, copper can form crystalline patterns or variegated surfaces when cooled slowly or under specific kiln conditions.

Firing temperatures for copperglazed wares vary with the glaze system, often spanning traditional stoneware and porcelain ranges. Achieving reds typically requires a reduced kiln atmosphere and careful control of temperature, while greens are more common in oxidizing conditions. Opacifying or color-modifying additives such as tin oxide or zinc oxide may be used to influence the final appearance.

Historically, copper glazes have been important in East Asian celadon ware, as well as Islamic and Ottoman maiolica and Iznik ceramics, and remain widely used by modern potters. Copperglazed surfaces can be found on stoneware, earthenware, and sometimes porcelain, with contemporary artists exploring color variety and surface texture.

Care and safety considerations include ensuring glaze formulations are lead-free and food-safe for functional ware, accurate firing according to the glaze recipe, and proper handling of copper-containing glazes to avoid staining or inhalation of powders during preparation.