A colourant is something added to something else to cause a change in colour. Colourants can be dyes, pigments, inks, paint, or chemicals. For example, this could be adding white to tint a paint, or black to shade a paint, ultimately changing the colour or value.
In foods, colourants are food additives, and as such are given a uniform identification code called an E Number. Not all materials with E Numbers are colourants, just those that are in the range E100-E199.
