What Two Qualities Are Needed For A Substance To Be A Dye?

The basic two qualities necessary for a dye are its colour and the affinity it shows to the substance that it dyes. The basic reason why a dye is used is to add colour to another substance and the quality of the dye is determined by the capacity of the dye to stick to the material it is applied to. A dye is considered best when the colour does not leave the material on being washed etc. Several different kinds of dyes exist including acid dyes, basic dyes, mordant dyes, direct or substantive dyes, vat dyes, Azo dyeing, disperse dyes, sulphur dyes etc.

There are food dyes also that are used as additives in food as well and are manufactured using a high standard. Traditionally the Plant Kingdom has been the greatest source of dyes.