Picture Details
Indigo factory
Partner:
Kew GardensImage reference:
ceb0042Origin:
Indian SubcontinentArtist / Date:
Christopher Rawson, 1900Size:
113 x 151 mmDescription:
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Blue indigo dye is yielded from the green leaves of the plant through a process of fermentation and oxidation. Traditionally the fermentation was carried out naturally by bacteria, harvested plants were packed into tanks and covered with water. The leaves would become saturated after a few hours and then fermentation began. This generated the thick layer of bubbles and scum on the surface of the vat. As soon as the liquid tasted sweet and was a dark blue colour it was siphoned off into another vat at a lower level, leaving the plants behind. The next stage of the process was oxidation, the dark blue liquid needed continuous stirring for several hours to get air into the mixture, this was often done by workers who would get into the vats to tread up and down, stirring it around. Eventually the liquid would change to a yellow-brown colour with the blue indigo patches floating on top, after leaving to rest these insoluble indigo patches would settle to the bottom of the tank as a blueish sludge. The water could then be drained off and filtered to remove impurities and to stop the enzyme reaction which made the indigo.
