biology, pigment is any material resulting
color in plant or animal cells which is the result of
selective absorption. Some biological material has so-called
structural color, which is the result of selective reflection
iridescence, usually done with multilayer structures.
Unlike structural color, pigment color is the same for all
viewing angles. Nearly all types of cells, such as
hair contain pigment. Butterfly wings typically contain
structural color, although many of them contain pigment
as well. Creatures that have deficient pigmentation are
Because pigment color is the result of selective
absorption, there is no such thing as white pigment. A white
object is simply a diffuse reflecting object which does
not contain any pigment.
In the coloring of
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 no well-defined dividing
line between pigments and dyes, however, and some coloring
agents are used as both pigments and dyes. In some cases,
a pigment will be made by precipitating a soluble dye with
a metallic salt. The resulting pigment is called a "lake".
List of pigments