Indian Yellow is a raw pigment which, as the name suggests, originated in India in the 17th century and was used until the early 20th century. Its source remained a mystery for many years. In 1786 the amateur painter, Roger Dewhurst recorded in letters to friends, that Indian yellow was an organic substance made from the urine of animals fed on turmeric (Myers, pg 1). Around this time, the English chemist George Field claimed it was made from camel urine. In 1839, J.F.L. Merimee, denied its association with urine in spite of its odor, citing its origin was a shrub called ‘memecylon tinctorium’ in his book ‘The Art of Painting in Oil and Fresco’, In 1886 the Journal of the Society of Arts in London began a systematic inquiry of the pigment, revealing that Indian yellow was manufactured in rural India (in particular in Monghyr, a city in Bengal) from the urine of cattle fed only on mango leaves and water (Finlay, pg 216-217). The collected urine was heated in order to precipitate the yellow matter, then strained, pressed into lumps by hand and dried, producing foul-smelling hard yellow balls of raw pigment, called ‘purree’ (Mukharji, pg 16-17). European importers would then wash and purify the balls, separating greenish and yellow phases.
It is the mango not the urine that's crucial to the color. The colorant is a magnesium salt of an organic acid released by the mango. Chemically it is magnesium euxanthate, the magnesium salt of euxanthic acid.
Naturally, the cows that were exploited by this process were extremely undernourished. In part because mango leaves did not supply the cattle with sufficient nutrients along with the fact that these leaves contain the toxin urushiol, also found in poison ivy. In 1908, British law (which
applied to colonized India) prohibited the production of Indian yellow, citing the torture of sacred animals.
The pigment is believed to have first been used in Europe by Dutch artists in the 17th...