Cochineal is a brilliant red dye from parasitic insects feeding on cacti. Requires 25,000 live or 70,000 dried insects for one pound of dye. Ancient Mesoamericans cultivated insects on cacti since 2nd century BCE. Production spread through Spanish colonial plantations in Mexico and South America
Allura Red AC is a dark red powder with CAS number 25956-17-6. Maximum absorbance occurs at about 504 nm. Soluble in water, slightly soluble in 95% ethanol. Available as sodium, calcium, and potassium salts
Green S is a synthetic coal tar triarylmethane dye with formula C27H25N2O7S2Na. Has E number E142 as food dye. Used as vital dye for staining living cells