Pigments are materials that change the colour of transmitted or reflected light due to the effect of a wavelength-selective absorption. The physical process that creates colour pigments is different from phosphorescence, fluorescence and other types of luminescence which involves the emission of light by a material.
The materials used as pigments have special properties which are capable of colouring other materials. Pigments should have high tinting strength comparative to the materials they colour.
colourants such as iron oxides and ochres have been used since prehistoric times. Archaeological discoveries showed that paint has been used by early humans for aesthetic purposes, including as body decoration. The period before the Industrial Revolution, there was limited range of colour used for art and decoration. Some of the common pigments in used then were mineral and earth.
- Biological Pigments: A colour pigment of biological origin is difficult to acquire. The botanical material was harvested and then traded over long distances. Some colours were difficult or costly to mix with available pigments. For this reason alone, purple and blue are associated with royalties because of the high cost of producing them. It used to be that the production of biological colour pigments was a big industry secret because of the difficulty of acquiring them.
- Mineral Pigments: Just like biological pigments, a mineral pigment is also traded from faraway places. The deep rich blue colour pigment of ultramarine can only be achieved by the use of lapis lazuli, a semi-precious stone, which was sourced from a remote area.
The Industrial Revolution and Scientific Revolution gave birth to a wide range of synthetic colour pigments. These are pigments that were refined or manufactured from natural materials. The synthetic pigments are used both for artistic and manufacturing applications.
The first modern synthetic colour pigment is the Prussian blue which was accidentally discovered in 1704. The range of blue colours expanded in the 19th century, to include metallic and synthetic blue pigments, including cobalt, French ultramarine and Cerulean Blue.
In the 20th century, the organic pigment Phthalo Blue, which has overwhelming tinting power, was added to the expanding range of blue colour pigments.
The development of dyes and chemical pigments helped brought industrial prosperity to many countries, especially in northern Europe. And the expanding discoveries and developments in colour science have created new industries as well as remarkable changes in taste and fashion.