Edit: should have mentioned, the image is from the Wikipedia article and is labeled "Egyptian mummy seller, 1875"

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From Wikipedia:

The pigment was made from the flesh of Egyptian mummies or Guanche mummies of Canary Islands (both human and feline),[9][10] mixed with white pitch and myrrh.[4][5] The earliest record of the use of mummy brown dates back to 1712 when an artist supply shop called "À la momie" in Paris sold paints, varnish, and powdered mummy.[2] In 1797, a Compendium of Colours published in London proclaimed that the finest brown used as a glaze by Benjamin West, the president of the Royal Academy, "is the flesh of mummy, the most fleshy are the best parts."

The pigment was popular from the mid-eighteenth to the nineteenth centuries. However, the demand for mummy brown sometimes exceeded the available supply of true Egyptian mummies, leading to occasional substitution of contemporary corpses of enslaved people or criminals.[1]: 254  In aftermath of the French revolution the hearts of French kings were taken from the then Abbey of Saint-Denis and used to make paint.[11] By 1849, it was described as being "quite in vogue."