One of the most important visual factors of carpet is color. Generally, chromogenic substances can be categorized as follows :

1-     Pigments :

These are soluble in organic solvents and are not used in dyeing.

2-     Chromatins (bases) : 

Chromatic substances absorbed by materials either via the absorbtion phenomenon or through diffusion (penetration). They are soluble in water and are divided into two natural and chemical types.