Interesting fact about Indian Yellow used for "Yellow Roses"

#art history
One of the colours I used for my yellow roses oil painting was Indian Yellow.
This is a wonderful rich yellow - reminiscent of curry!

palette for the painting of yellow roses which included Indian Yellow

 

Indian yellow came to England in 1786 and its method of production was kept secret.  No surprise why, as it was made by heating the urine of cows fed on mango leaves (nothing else)!
The poor cows wasted away because of their diet. The method became public in the late 19th century. It was subsequently stopped in 1908.

A great way to get over health and safety when I taught regular watercolour classes was to relate this tale.  Those that sucked their paint brushes to get a nice point soon stopped!!!!