India's Blue Gold

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Indigofera Tinctoria.L is  a leguminous shrub that grows to the height 1.5metres in height, it is cultivated widely in the tropical regions of India. Many sources record the plant as being native to India and the Malaysian archipelago and now naturalised through cultivation in pats of Africa and temperate Asia. The plant is propagated through seeds. The leaves are pinnate and flowers are pink to purple.

A leguminous plant, it is known for its high nitrogen content and is grown as groundcover for improving soil quality. It is also cultivated as green manure for use in rice cultivation in regions of India and the Phillipines. The plant is known world over for its ability to produce a fast blue dye, Indigo.

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History

Carl Linnaeus, father of taxonomy, has described Indigofera L. as the largest genus of the tribe Indigofereae of the Fabaceae family. Indigofera tinctoria or true indigo have been described by Linnaeus as the primary source of blue dye.

Marco Polo , a 13^th century Italian explorer has recorded in his book the “Travels of Marco Polo”, about the preparation of Indigo in India. The Greek historian Herodotus has recorded in 450 BC that indigo was imported from India in “cakes “

Persian scholars used indigo inks and paints and so did ancient European artists. Ayurvedic texts prescribe Indigo for treating conditions of hair, skin, cancer, problems of liver, skin, insect and animal bites. Chinese medicine suggests indigo for the treatment of fever, inflammation and purification of blood and the liver.

Modern research has also recorded the ability of Indigo to cure and treat several ailments.

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Indigo Dye

Production Method - Kongarapattu region, Villupuram District, Tamil Nadu.

The plant is allowed to reach the height of around a metre and is harvested before its begins to bloom. Harvest takes place in the early hours of the day just after sunrise. The freshly harvested stems are transported to a dye production unit within the farm itself. The production unit usually consists of 2 -3 large tanks built out of concrete. The harvested stems are dropped into tanks filled with water and allowed to ferment for 12 hours or so. The fermented indigo stems are then manually aerated with a specific kicking action by men, who stand in the tanks and kick rhythmically. The water turns blue as the invisible indigotin pigment oxidises. The blue water from the tank is allowed to run into the second collection tank after the blue sludge like indigo pigment settles down into the bottom of the tank. The indigo sludge  is scooped manually and collected into big steel pots and cooked in a vessel for a few hours. Once it reduces to a thick clayey paste, the indigo paste is allowed to cool and cut into squares.

The indigo cakes are then ready for dyeing and are exported all over the world. The dye cakes are then used added into special fermentation vats by Indigo dyers who carefully tend their vats and dip dye fabric or yarn to get a lasting blue.

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Please refer to the video below to view the actual harvest and dye cake making process, filmed by Dolmann pictures, Auroville , shot at KMA Farms, Kongarapattu Village, Villupuram  district, Tamil Nadu.

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