A pigment is distinguished from a dye in that a dye is fully dissolved in the medium whilst a pigment is distributed through the medium in suspension. Dyes may be turned into pigments by fixing the dye onto an inert base, coloring that base. The dyed base will then be finely ground and suspended in the relevant medium.
Most pigments used throughout history have been naturally occurring substances. Technological developments have enabled these substances to be synthesized and new pigments to be developed. This has greatly increased the variety of pigments available and reduced their cost.