indigo (redirected from Indigo (colour))

indigo [Span.; from Lat.,=Indian], important blue dyestuff used in printing inks and for vat dyeing of cotton (see dye). It was anciently produced in India and was known in Egypt, probably c.1600 B.C.; mummies of the XVIII dynasty have been discovered wrapped in indigo-dyed cloth. Indigo is obtained from leguminous plants of the genus Indigofera, chiefly from the Asian species Indigofera tinctoria, but also from several other species. The plants contain a colorless, soluble glucoside called indican. When the macerated plants are allowed to ferment in vats of water the colorless form of indigo is liberated; stirring of the liquid causes oxidation of the colorless material to form a blue sediment. The natural indigo gives a strong blue color of great permanence. Use of the natural dye greatly decreased after the synthesis of indigo was accomplished. Adolf von Baeyer was the first to synthesize it, but others developed the methods used for its commercial production from aniline and chloroacetic acid.

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indigo

Blue vat dye, obtained until about 1900 entirely from some species of the indigo plant. Extraction of the dye was important to the economy of colonial America and remained so in India until the early 20th century. Synthetic indigo has replaced the natural dye; it is reduced chemically to the soluble yellow compound leucoindigo, in which form it is applied to textile fibres and reoxidized to indigo (see oxidation-reduction).

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(1) An earlier family of desktop graphics computers from SGI. The low end were the Indy machines, which included their own digital video camera. The high end included a variety of Indigo workstations, with models specialized for graphics functions such as accelerated texture mapping and image processing. See SGI.

(2) The code name of the messaging system in Windows Vista. See Windows Communication Foundation.