Coloured pigments and effect pigments
Complex inorganic coloured pigments cover a wide range of colour and chemical composition. This group of pigments represents crystal classes which can be widely found in nature – principally rutile and spinell. Those crystal lattices host metals, which are the reason of colour effects and crystal (chemical) stability. Important metals are nickel, cobalt, trivalent chromium, zinc, manganese, iron, titanium and antimony. Those metals lose their toxicological and ecological properties once incorporated into the crystalline host lattices. The toxicities of the pigments are equal to those of the host crystals. The colour spectrum obtained ranges from yellow to green, blue and black.
Effect pigments are a group of pigments, which receive their optical properties by reflection rather than absorption. The combination of transparent layers on a suitable support leads to interference and optically variable pigments. Combinations of effects results in colour effects dependant of the angle of observation. Metallic effect pigments are the basis of many automotive coatings extensively seen today. Special types are used in printing inks and plastic articles.
Complex inorganic coloured pigments and effect pigments are light and weather resistant and permit high temperature applications. Due to their high refractive index those inorganic pigments are often used in combination with organic pigments, especially when high hiding power is required.
This group of pigments is produced by a variety of companies, a number of which has specialized on certain products. For further information please see members (full description).
Technical, ecotoxicological and legislative information can be found in the brochures "Safe handling of pigments" and "Colourants for food contact plastics".