In the coloring of paint , ink , plastic , fabric and
other material, a pigment is a dry colorant, usually
an insoluble powder. There are both natural and synthetic pigments,
both organic and inorganic ones. Pigments work by selectively absorbing
some parts of the visible spectrum (see light )
whilst reflecting others.
A distinction is usually made between a pigment, which is insoluble,
and a dye , which is
either a liquid, or is soluble. There is a well-defined dividing line
between pigments and dyes: a pigment is not soluble in the vehicle
(or matrix) while a dye is . From this follows that a certain
colourant can be both a pigment and a dye depending on in which vehicle
it is used. In some cases, a pigment will be made by precipitating
a soluble dye with a metallic salt. The resulting pigment is called
a " lake ". Fugitive
pigments are non-permanent pigments.
