The difference between pigments and dyes

The use of a dye to see color can also be achieved because they dissolve directly in the plastic or ink system. The color of pigments depends on spreading finely insoluble solids in the paint solvent, without first dissolving them to achieve the goal. A useful example is the yellow substance flavanthrone (Indanthrin Yellow), which has exactly the same chemical composition and can be used as a dye or as a pigment.

When used as a dye, they are first chemically reduced to an alkali-soluble reduced form or a leucorform. This solution is then applied to textiles, oxidized, and fixed. On the fabric, reworking produces insoluble flavan2hrone. But when used as a pigment, flavanthrone is in a granular insoluble form and is directly dispersed in the oil or plastic body.

This dual nature of the colored matter, in terms of color index (CI), is the same in both cases, but has a different name, depending on the application. For example CI42040, there is a distinction between basic green 1 and Pigmentgreenl.