Ceramic colors are powdered metal oxides and other mixtures used in ceramic glazes to decorate ceramics, porcelain, and terracotta, and also in porcelain enamel to decorate metalware. Most ceramic  colors are off-white when in powder form; their rich, intense colors emerge when the piece is fired in a ceramic kiln or pottery kiln. Ceramic colors usually contain fluxes and certain ingredients that make them unfavorable for painting. Ceramic colors are called porcelain pigments in the UK.
The preparation process of ceramic colors:
1. mix
The final color tone of the colorant is greatly affected by other ingredients added to the colorant. Therefore, in order to make each batch of colorant emit the same hue, it is necessary to weigh and mix the raw materials with the same composition quality.
2. Calcination
Calcination is an important process for making ceramic  colors, and its purpose is to stabilize them. During the calcination process, different reactions occur due to the different properties of the raw materials and the different desired colorants. The minimum calcining temperature should be the same as the use temperature of the final product of the colorant.
3. Washing
After the calcined pigment is pulverized, it should be washed with water in order to remove all soluble substances. The pigment using chromate must be washed with hot water. If there is soluble chromate left, there will be uneven shades around the chrome. If the borate is not removed, it will produce a thin film on the color.
4. Crushing
After washing with water, use a disc mill or ball mill to grind to the required fineness by wet method. Although there is no specific regulation on the particle size requirements of ceramic  colors, it is generally required to pass through a 300-mesh sieve. Insufficient crushing will make it difficult to use due to uneven particle size, and lack of covering power will cause spots after firing. On the contrary, if the crushing is too fine as dust, it cannot be fully fused in the glaze and becomes the cause of rolling glaze.