Blue Dye Crossword Clue

Blue Dye Crossword Clue. A crossword question on May 25, 2017

The answer is ANIL for 4 letters, or WOAD or INDIGO for 6
letters

Indigo dye is an organic compound with a distinctive blue color (see indigo). Historically, indigo was a natural dye extracted from the leaves of certain plants, and this process was important economically because blue dyes were once rare. A large percentage of indigo dye produced today – several thousand tons each year – is synthetic. It is the blue often associated with blue jeans.

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 trousers 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. About 20 thousand tons are produced annually, again mainly for blue jeans. It is also used as a food colorant, and is listed in the United States as FD&C Blue No. 2.