Dyes and Pigment

Dyes/Dyestuff:
     Dyes are colored ,unsaturated organic chemical compounds capable of giving color to substrate.

why dye molecule are colored?
     Dye molecule are colored because they are selectively able to absorbed and reflect incident light.

     Dyes contain chromophore and auxochrome group.

     Chromophore gives the dye molecule it's particular color. A molecule processing no chromophore would be colorless.
     Auxochromes are organic radicals intensify the hue of the dye molecule's color ,makes the dye molecule more water soluble and improve the color fastness property of the dyed or printed fiber.

Pigment:
      Pigment are insoluble coloring matter mostly organic and inorganic(mineral origin) have been used for the coloration of metal wood,stone and textile material. Pigment molecule contain chromophore group but no auxochrome group,so they have no directly affinity to textile fibers. They are fixed on textile material with the help of resin binder. This binder which is usually  mixed  with the pigment ,acts like an adhesive. The two most common uses for pigments are printing operation and solution dyeing of polymer melt prior to extrusion of some synthetic fiber.

Difference between dyes and pigment:

Dye	Pigment
Water solubility 70%	100% water insoluble
Auxochrome persent	Auxochrome  not present
No binding agent required	Bindine agent required