what is the structure of indigo
Indigo is a deep and bright color close to the color wheel blue (a primary color in the RGB color space), as well as to some variants of ultramarine.The color indigo was named after the indigo dye derived from the plant Indigofera tinctoria and related species.he same indigo dye is contained in the woad plant, Isatis tinctoria, for a long time the main source of blue dye in Europe. Woad was replaced by true indigo as trade routes opened up, and both are now largely replaced by synthetic dyes.