Indigo is a deep and rich color close to the color wheel blue (a primary color in the RGB color space), as well as to some variants of ultramarine, based on the ancient dye of the same name. The word Indigo comes from the Latin for “Indian”, as the dye was originally imported to Europe from India.
The primary use for Indigo is as a dye for cotton yarn, which is mainly for the production of denim cloth for blue jeans. On average, a pair of blue jean pants requires 3-12 g of Indigo. Small amounts are used for dyeing wool and silk. Indigo carmine, or Indigo, is an Indigo derivative which is also used as a colorant.
