It involves extracting indigo precursors from freshly harvested plants by submerging them in a large tank . These precursors are hydrolyzed by heat and/or fermentation and subsequently alkalized and oxidized to produce insoluble indigo pigment, which precipitates and settles before being filtered and dried .

How is Neel made?

Historically, the Japanese have used another method which involves extracting indigo from the polygonum plant. In this process the plant is mixed with wheat husk powder, limestone powder, lye ash, and sake. The mixture is allowed to ferment for about one week to form the dye pigment which is called sukumo.

How was indigo made?

Historically, indigo was a natural dye extracted from the leaves of some plants of the Indigofera genus, in particular Indigofera tinctoria; dye-bearing Indigofera plants were commonly grown and used throughout the world, in Asia in particular, as an important crop, with the production of indigo dyestuff economically ...