Organic pigments are insoluble organic compounds that are usually added to a substrate in a highly dispersed state to give it colour.
The fundamental difference between dyes and dyes is that dyes dissolve in the dye used, whereas pigments do not dissolve in either the medium in which they are used or the substrate in which they are coloured.
Many pigments and dyes have the same chemical structure, and they can be converted into each other by different methods. For example, some VAT dyes and sulphide VAT dyes can be used as fiber dyes if they are reduced to a leucochromatid.
If not reduced, it can be used as a pigment for advanced inks.
Organic pigments are widely used in ink, paint, coating, raw material of synthetic fiber, pigment printing of fabric, plastic, rubber, leather, etc., among which ink pigments are used the most.
At present, organic pigments account for about a quarter of dye production.