dye
Substance that, applied in solution to fabrics, stains with a permanent colour. Different types of dye are needed for different types of fibres. Direct dyes combine with cellulose-based fabrics like cotton, linen, and rayon, to colour the fibres. Indirect dyes require the presence of another substance (a mordant), with which the fabric must first be treated, to ensure that the dye will remain ‘fast’ during washing. Vat dyes are colourless soluble substances that on exposure to air yield an insoluble coloured compound that is resistant to water.
Naturally occurring dyes include indigo and madder (alizarin), which are extracted from plants; logwood, produced from wood; and cochineal, a red dye made from crushed insects. Industrial dyes are usually synthetic and are derived from coal or petroleum. English chemist William Perkin developed the first synthetic dye, mauve, in 1856 and by the early 20th century a wide range of synthetic dyes was available.
