Powder blue became popular on porcelains in the Kangxi reign. The cobalt blue was blown onto the surface of the unfired porcelain body through a tube with gauze over the end. The effect, when fired, was of a deep, finely mottled or soufflé blue. In some cases the blue covered the whole piece, in others panels were reserved in white and decorated with overglaze enamels in a second firing. The powder blue surface was often embellished with gold designs.