The divide between synthetic indigo and natural indigo could not be wider. Natural indigo is produced from the indigo plant. Its production by natural composting and fermentation spanning a history of over 4000 years is culturally specific and the dyeing methods just as idiosyncratic. In its purest form, natural indigo production requires no chemicals, the waste water from this sustainable agricultural process is used to water crops, while the remaining solid waste is used as a bio-fertilizer.
On the synthetic indigo side, there are concerted efforts being made to eliminate the need for sodium hydrosulfite in the dyeing process which would greatly improve its environmental profile. Processes to 'green up' the dyeing, such as the use of biotechnology, look promising, but at this point the technology is expensive.
Synthetic indigo production is a huge industry and the path to change is a slow one. That change is consumer driven and with informed demand will come more research and development and then increased supply options, leading to a much cleaner environment.
Indigo dye protects the wearer against skin diseases. Its ability to provide the beautiful blue hue has made it a preferred option for the apparel makers. When applied on clothes it cures giddiness, abdominal dieses and spleen disorder.
Natural Indigo offered us contains a very high percentage of Indigotin (40%).
It is available both in cake and powder form.