ABSTRACT
Abstract: Vat dyes retain C=O chromophore in structure, which renders water insolubility. Dyes are reduced and solubilised for application from aqueous media, when the dye shows affinity and substantivity for cellulosics. Rate of exhaustion is excellent with higher strike rate which raises chances of unlevelled dyeing. Shades possess all round colourfastness and are brilliant. All hues are available with high tinctorial power. Reduction process is little complicated; any mishandling may over-reduce dye changing hue and shade. Sodium hydrosulphite (Na2S2O4) used for reduction of vat dyes increases wastewater load abruptly, forcing to search for alternate reducing systems.
