Dyes
Carmine dyes, which give crimson and related red and purple colors, are based on an aluminium and calcium salt of carminic acid. Carmine lake is an aluminium or aluminium-tin lake of cochineal extract, and Crimson lake is prepared by striking down an infusion of cochineal with a 5 percent solution of alum and cream of tartar. Purple lake is prepared like carmine lake with the addition of lime to produce the deep purple tone. Carmine dyes tend to fade quickly.
Carmine dyes were once widely prized in both the Americas and in Europe. They were used in paints by Michelangelo and for the crimson fabrics of the Hussars, the Turks, the British Redcoats, and the Royal Canadian Mounted Police.
Nowadays carmine dyes are used for coloring foodstuffs, medicines and cosmetics. As a food additive in the European Union, carmine dyes are designated E120, and are also called cochineal and Natural Red 4. Carmine dyes are also used in some oil paints and watercolors used by artists.
Read more about this topic: Crimson