Inorganic pigments are usually salts and carbon black such as metallic oxide, sulfide, sulfate, chromate, and molybdate, etc. Since they are from nature, they have good heat resistance, light resistance and strong hiding power, without transference, and they can be used for any plastic. Their disadvantages are their transparency, color and luster, and tinting strength are relatively poorer, and the cadmium toner contains lead, a harmful element to the human body. Therefore, it cannot be used in children's toys. Most of the Rainbow pigments have passed the EN71-3 European standard.