Mechanism of reduction of oxidation of indigo dyes

Figure 1: Mechanism of reduction of oxidation of indigo dyes

Below the figure shows these dyes have to be reduced before coloration to be transferred into the water-soluble form which have to toward fibers and which after absorption into the fibers to be dyed, must be re-oxidized to the pure water-insoluble dye pigment make the fibers.

Figure 2: Mechanism of reduction of oxidation of VAT dyes.

In a conventional system, most of the dyes mechanism is used as above. Below I want to show the worldwide dyes consumption of cellulosic fibers.

Figure 3: Mechanism of reduction of oxidation of sulfur dyes.