Conventional and modern techniques are discussed

Conventional and modern techniques are discussed below:

Conventional technique

Electrochemical reaction: In the coloration of cellulose fibers, vat dying with sulfur dyes still give a relatively maximum part of the dyestuff market. The situation will remain constant also in the upcoming future.

Mainly because vat dyes yield colored fibers of excellent all-round rapidness, particularly to light, washing, and chlorine bleaching. Sulfur dyes are prerequisite for the production of cheap products having average fastness requirements. The dyes are very quick to light and washing, but not to chlorine.

Figure 1: Mechanism of reduction of oxidation of indigo dyes