Indigo

A deep blue pigment prepared from the leaves and branches of a small shrub; it is transparent, tolerably permanent, and mixes well with other pigments, forming excellent greens and purples. A deep brown, known as indigo brown and a deep red resin, known as indigo red, may be extracted by purifying the blue colour obtained from this dye. The old blue dye of the aboriginal Britons was produced from woad (is at is tinct or i a). ( Fairholt. ) (See Intense Blue.)