They are mainly based on carbon, hydrogen, and nitrogen and can be classified in three main groups: azo pigments, polycyclic pigments, and anthraquinone pigments. They are all artificially synthetic organic compounds. The organic pigment has no affinity to the colored substance, instead being attached to the surface of the colored substance through adhesive or film-forming material to achieve the purpose of coloring the object. Organic pigment is a class of insoluble organic compounds of high coloring strength. The so-called insolubility means that they have extremely small solubility in water, organic solvent, and various kinds of media. Organic pigments are mainly applied in the ink (50%), paint (25%), plastics (12%) and rubber (10%), four areas with other areas only accounting for about 3%.