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Columbia Encyclopedia entry: indigo
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.
Wikipedia search results for: Indigo
From Wikipedia, the free encyclopedia
Indigo is the color on the electromagnetic spectrum between about 420 and 450 nm in wavelength, placing it between blue and violet. Although traditionally considered one of seven divisions of the optical spectrum, modern color scientists do not usually recognize indigo as a separate division and generally classify wavelengths shorter than about 450 nm as violet. Those who do accept indigo as a separate spectrum color regard its wavelength as being from approximately 420 nm to 450 nm. Like violet, whether indigo is considered a shade of purple depends on context. Common English usage defines a purple color as any color between red and...more »
Columbia Encyclopedia search results: indigo
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  • woad

    Woad, name for a perennial plant (Isatis tinctoria) of the family Cruciferae (mustard family) and for a blue dye obtained from its leaves. The plant is believed to be native to S Russia, but w...

  • dye

    Dye, any substance, natural or synthetic, used to color various materials, especially textiles, leather, and food. Natural dyes are so called because they are obtained from plants (e.g., aliza...

  • bunting

    Bunting, common name for small, plump birds of the family Fringillidae (finch family). Among the American buntings are the indigo bunting, in which the summer plumage of the male reflects sunl...

  • Baeyer, Adolf von

    Baeyer, Adolf von (Johann Friedrich Wilhelm Adolf von Baeyer), 1835–1917, German chemist. He taught at Berlin and Strasbourg and in 1875 succeeded Liebig at Munich. For his work in organic che...

  • Schliemann, Heinrich

    Schliemann, Heinrich, 1822–90, German archaeologist, discoverer of the ruins of Troy. He accumulated a fortune in the indigo trade and as a military contractor and retired from business in 186...

  • Georgetown, cities, United States

    Georgetown. 1 Town (1990 pop. 11,414), Scott co., N central Ky., in the bluegrass country; settled 1776, inc. 1790. In a rich agricultural, dairying, and livestock area, Georgetown also has li...

  • Mitchell, Joni

    Mitchell, Joni, 1943–, Canadian songwriter, singer, guitarist, poet, and painter, b. MacLeod (now Fort Macleod), Alta., as Roberta Joan Anderson; married musician Chuck Mitchell (1965–67). She...

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    Racer, name for several related swift, slender snakes, especially those of the genus Coluber. All of the racers are nonpoisonous, nonconstricting, day-active snakes. The black racer, C. constr...

  • Ellington, Duke

    Ellington, Duke (Edward Kennedy Ellington), 1899–1974, American jazz musician and composer, b. Washington, D.C. Ellington made his first professional appearance as a jazz pianist in 1916. By 1...

  • Guizhou

    Guizhou or Kweichow, province (1994 est. pop. 33,800,000), c.66,000 sq mi (170,940 sq km), SW China. Guiyang is the capital and chief city; Zunyi and Duyun are important towns. Guizhou is almo...

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