Woad was replaced by true indigo as trade routes opened up, and both plant sources have now been largely replaced by synthetic dyes. For a long time, woad was the main source of blue dye in Europe. īlue dye can be made from two different types of plants: the indigo plant, which produces the best results, and from the woad plant Isatis tinctoria, also known as pastel. Before the Revolutionary War, indigo accounted for more than one-third of the value of exports from the American colonies.

In North America, indigo was introduced by Eliza Lucas into colonial South Carolina, where it became the colony's second-most important cash crop (after rice). The English and French subsequently began to encourage indigo cultivation in their colonies in the West Indies. Spanish explorers discovered an American species of indigo and began to cultivate the product in Guatemala. The Ancient Greek term for the dye was Ἰνδικὸν φάρμακον ( indikon pharmakon, 'Indian dye'), which, adopted to Latin as indicum (a second declension noun) or indico (oblique case) and via Portuguese, gave rise to the modern word indigo. It was imported from there in small quantities via the Silk Road. Pliny the Elder mentions India as the source of the dye after which it was named. The earliest direct evidence for the use of indigo dates to around 4000 BC and comes from Huaca Prieta, in contemporary Peru.

Indigofera tinctoria and related species were cultivated in East Asia, Egypt, India, Bangladesh and Peru in antiquity. Main article: Indigo dye § History Extract of natural indigo applied to paper The first known recorded use of indigo as a color name in English was in 1289. It is traditionally regarded as a color in the visible spectrum, as well as one of the seven colors of the rainbow: the color between blue and violet however, sources differ as to its actual position in the electromagnetic spectrum. The word 'indigo' comes from the Latin word indicum, meaning 'Indian', as the plant-based dye was originally exported to Europe from India. Indigo is a deep 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.

Indigo dyes