An innovative approach to indigo dyeing

Indigo, originally derived from plants, is the dye used to produce the colour of denim. The textile industry widely employs sodium hydroxide and sodium hydrosulphite to effect indigo dyeing. Commercial efforts are concentrated in reducing waste, effluent load and consumables so as to apply indigo in a sustainable manner. This and the growing global market for denim dyed using natural indigo fosters current academic research. This paper reports the possible use of benign auxiliaries (thiourea dioxide and sodium carbonate) and evaluates the pad-steam process for dyeing with indigo. Ideal dyeing parameters are outlined. The study concludes that indigo dyeing can be achieved using methods that have a reduced impact on the environment as compared to existing industrial processes