Carmine (Cochineal)

These images are carmine's chemical structure, a sample of the raw material and an example of its use from the museums's collection.

Carminic Acid

• The pigment was first used ~700 BCE.
• Carminic acid functions to deter predation by other insects.
• The acid is extracted from insect's body and eggs, and is mixed with aluminium or calcium salts to make carmine dye.
• In Mexico, cochineal scale (Dactylopius coccus) preys on the prickley pear cactus; the dye typically constitutes 17-24% of this insect's dry weight. Aztec and Mayan Indians used the dye extensively.
• Polish cochineal (Porphyrophora polonica) is native to the Polish-Lithuanian-Ukranian region, grows on the roots of knawel, a carnation, and contains 0.6% carminic acid. 
• Today, carmine (which is NOT the USDA red #40) is primarily used as a colorant in food and in lipstick.

These blogs were inspired by a 2017 show at the Indianapolis Museum of Art called CSI: Chemistry of Color.