Colorant compound:

A substance used for coloring a material. Colorants are used in many industries - to colour clothes, paints, plastics, photographs, prints, and ceramics. 

Colorants can be either dyes or pigments. Dyes are soluble coloured organic compounds that are usually applied to textiles from a solution in water. They are designed to bond strongly to the polymer molecules that make up the textile fibre.Pigments are insoluble compounds used in paints, printing inks, ceramics and plastics. They are applied by using a dispersion in a suitable medium. Most pigments used are also organic compounds.