Tattoo ink contains pigments suspended in a carrier. According to a November 2007 article in Chemical and Engineering News, some materials used as carriers are witch hazel, glycerin, alcohol and water.
Black ink usually contains iron oxides, carbon or logwood. According to the Museum of Tattoos, it may also contain magnetite crystals, powdered jet, or soot.
White ink may contain lead white, titanium dioxide or zinc oxide.
These inks may contain ochre, iron oxide, napthol, disazodiarylide and cadmium selene-sulfide.
Pigments commonly used for these colors are cadmium yellow, curcuma yellow, chromium oxide, malachite, ferrocyanides and lead chromate.
These may contain azure blue, cobalt blue, Cu-phtalocyanine, manganese violet, dioxazine or aluminum salts.