Pigment

In biology, pigment is any material resulting in 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 or 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 skin, eyes, fur and hair contain pigment. Butterfly wings typically contain structural color, although many of them contain pigment as well. Creatures that have deficient pigmentation are called albinos.

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 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 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".

List of pigments

Heme/Porphyrin based
Chlorophyll
Bilirubin
Hemocyanin
Hemoglobin
Myoglobin

Light emitting

Luciferin

Lipochromes

Carotenoids
Alpha and Beta Carotene
Cyanins
Anthocyanin
Lycopene
Rhodopsin
Xanthophylls
Canthaxanthin
Zeaxanthin
Lutein

Photosynthetic

Chlorophyll
Phycobilin

Other

Hematochrome
Melanin - Which causes human skin coloration
Phthalocyanine blue
Urochrome
polyene enolates are a class of red pigments unique to parrots.

Painting pigments

Alizarin (Alizarin Crimson)
Bone black (also known as bone char)
Cadmium pigments (Cadmium Green, Cadmium Red, Cadmium Yellow, Cadmium Orange)
Caput Mortuum
Carbon black
Cerulean blue
Chromium pigments (Chrome Green, Chrome Yellow)
Cobalt pigments (Cobalt Blue)
Crimson
Fugitive pigments
Gamboge
Indian Yellow
Indigo
Ivory black
Vine black
Lamp black
Mars black
Lead pigments (Lead white, Naples Yellow, Cremnitz White, Foundation White, Red Lead)
Paris Green
Phthalocyanine (Phthalo Green, Phthalo Blue)
Prussian blue
Quinacridone (Quinacridone Magenta)
Oxide Red
Red ochre
Sanguine
Sienna (Raw Sienna, Burnt Sienna)
Titanium dioxide (Titanium White)
Ultramarine (Ultramarine Green Shade, French Ultramarine)
Umber (Raw Umber, Burnt Umber)
Van Dyke brown
Venetian Red
Verdigris
Vermillion
Viridian
Yellow ochre
Zinc white