Where does indigo dye come from?
Asian plants, mostly Indigofera tinctoria (aka
Indigofera sumatrana) were the original source for the
dye, with several thousand square kilometers of the plants grown in
India around 1900.
A variant found in the Americas is Indigofera suffruticosa, known as añil in the West Indies. The name for now-synthetic aniline dyes comes from this name.
The use of indigo, which is a dye that can come from at least 5 different plants, was first used in the 7th century, BC. The plants from which indigo dye came were most likely weeds. No one knows who may have started raising plants containing indigo, as it was so long ago. Today, man-made indigo dye (not from plants) is the color used in blue jeans.
Indigo has to be converted to the leuco-base form in a dye bath because indigo is insoluble in water and has to be converted to a water-soluble form through an oxygen-reduction process. This action produces luecoindigo which it used to dye clothes. The clothe can be converted back to an indigo form thereafter by air drying.
The traditional dye for jeans is indigo. Natural Indigo dye is uncommon in that it does not require a mordant. The thread (fibre) or in some cases the woven cloth is soaked in a vat of the dye. Repeated submerging result in a darker colour. For complete instructions and further information see the related link below.
Indigo has been used by various historical cultures. In the East, indigo was used for batik fabrics. The indigenous tribes of the Americas used indigo for painting and as mummy shrouds. In North and West Africa, indigo-dyed cloth symbolizes wealth and fertility; powerful people use indigo for clothing and skin dye.