The ink sac of cuttlefish supplies a brown dye called sepia.
Manufacturer / product code: Kremer 12401
Chemical description: 78% melanin, 10% calcium carbonate, 7% magnesium carbonate, 2% alkaline sulfates and chlorides and 0.8% miscellaneous compounds.
Color Index: NBr 9
More info: Kremer PDF
It was used in the 18th century as a brown pigment in ink painting, illustration and calligraphy.