The pigment plays a significant role in the ink, and it has a direct impact on some characteristics of the ink.

Pigments are colored, black or white high-dispersion powders that are insoluble in water and organic solvents. According to their source and chemical composition, they are divided into two categories: organic pigments and inorganic pigments.

① Inorganic pigments are oxides of non-ferrous metals, or some metal insoluble metal salts. Inorganic pigments are divided into natural inorganic pigments and artificial inorganic pigments. Natural inorganic pigments are mineral pigments.

②Organic pigments are colored organic compounds, which are also divided into two categories: natural and synthetic. Nowadays, synthetic organic pigments are commonly used. There are many varieties of organic pigments, more complete colors, and better performance than inorganic pigments.

Dyes are organic compounds, which are soluble in water and sometimes in organic solvents. From certain dyes, insoluble colored precipitates, called lake pigments, can be prepared for printing inks.

The pigments used in printing inks have high requirements, especially the color, dispersion, light resistance, transparency, etc. The color pigments are required to have a hue close to the spectral color, and the saturation should be as large as possible. The magenta, cyan, and yellow used in the three primary color inks The transparency of the pigment must be high. All pigments must not only be water-resistant, but also be quickly and evenly combined with the binder. The oil absorption capacity of the pigment should not be too large. The pigment should preferably have alkali resistance, acid resistance, alcohol resistance and potential resistance.