Dyes and pigments are substances that impart color to a material. The term colorant is often used for both dyes (also called dyestuffs) and pigments. The major difference between dyes and pigments is the particle size. Dyes are much finer than pigments. Therefore dyes are not UV stable whereas pigments are usually UV stable.

Dyes, also known as colorants in which the coloring matter is dissolved in liquid, are absorbed into the material to which they are applied.