Denim Indigo Dyeing – The use of indigo as coloring matter for textile materials is often traced to the past. When natural plants and animal derivatives were the sole known sources of dyes. Wonderful linen fabric with fine indigo-dyed borders has survived to this from Egyptian tombs dating from around 2400 BC.
From these times and until the top of the nineteenth century. Indigo was produced exclusively from various plants. Like Indigofera tinctoria. The primary indigo dyeing procedures used fermented or bacterial indigo dyeing baths. it had been discovered way back that if indigo leaves were left to rot in the urine.
Green Solution – Denim Indigo Dyeing
The colour was realized and a green solution was created. The urine provides both the nutrients to grow the bacteria that reduce indigo and also the ammonia that produces the alkaline solution. When natural textiles like cotton, linen, wool, and silk were impregnated during this dyeing bath, they turned green. However, once they were taken out and exposed to air, the green color quickly changed to blue. Each region of the planet developed its own dyeing methods from this process, which depend especially on the type of indigo bearing plants present also because of the design of its traditional garments.
In the course of your time, various developments were made in fermented indigo dyeing baths. Probably this was achieved so as to avoid or decrease the worst smell caused by urine fermentation. Many substances were introduced in dye baths to make and accelerate the fermentation process, like wheat bran, madder roots, dates, raisins, honey, plant seeds, and glucose.
The alkalinity of the medium was ensured by adding lime or sodium carbonate. Soda ashes were exclusively obtained from plants including glass-wort, saltwort, kelp, and mangrove. The dye bath that was used took a few weeks to ferment. the color of the dyeing bath was light yellow. However, people understood later that if it’s bright yellow, it means an excessive amount of alkalinity, and more indigo should be added. If the color in Denim Indigo Dyeing is just too dark, it needs more lime or another alkali. This vat might be maintained during a functional state for several months.
Indigo bearing plants were the sole source of blue dye within the world. With increasing world trade, demand for blue garments rose. The fermentation dyeing technique was time-consuming. This presented a crucial difficulty in rapidly fulfilling merchants’ orders.
However, since 1730, this example has been improved with the event of the Copperas vat. during this technique, prepared indigo is added to a mix of Copperas (ferrous sulfate) with lime or potash. The reduction to the Leuco indigo proceeded without heating and it took only 24 h.
This lowered the general cost also because of the time of dying. The Copperas vat was exclusively applied for dyeing of cotton skein yarns because it had been too alkaline to be used with wool. Its principal advantage is that it’s easy to organize and confine conditions.