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.