Indigos

Indigos refer to topics related to the color indigo and to the dyes produced from certain plant species. In color theory, textiles, and culture, the term is used for both a hue and the substances that yield it.

The color indigo lies in the visible spectrum between blue and violet, with roughly 445 to 464 nanometers wavelength. It is traditionally listed as one of the seven rainbow colors. In contemporary design, the web colour indigo is commonly represented by the hex value #4B0082.

Indigo dye is historically obtained from plants in the genus Indigofera, especially Indigofera tinctoria. Leaves are processed to release indican; through fermentation and oxidation, indigo precipitates as a deep blue dye suitable for vat dyeing. A synthetic version of indigo, developed in the late 19th century, now dominates production, but natural indigo remains produced in some regions. Other natural sources include Isatis tinctoria (woad) and Polygonum tinctorium (Japanese indigo).

Indigo dyes have played a significant role in textile history, notably in denim and traditional garments across various cultures. The association of indigo with deep blue fabrics has influenced fashion, art, and symbolism, and the color indigo is used in branding and design to convey depth and mood.