Manufacturers are not required to reveal their ingredients or conduct trials, and recipes may be proprietary. Professional inks may be made from iron oxides (rust), metal salts, plastics. Homemade or traditional tattoo inks may be made from pen ink, soot, dirt, blood,or other ingredients.
Heavy metals used for colors include mercury (red); lead (yellow, green, white); cadmium (red, orange, yellow); nickel (black); zinc (yellow, white); chromium (green); cobalt (blue); aluminium (green, violet); titanium (white); copper (blue, green); iron (brown, red, black); and barium (white). Metal oxides used include ferrocyanide and ferricyanide (yellow, red, green, blue). Organic chemicals used include azo-chemicals (orange, brown, yellow, green, violet) and naptha-derived chemicals (red). Carbon (soot or ash) is also used for black. Other compounds used as pigments include antimony, arsenic, beryllium, calcium, lithium, selenium, and sulphur.
Tattoo ink manufacturers typically blend the heavy metal pigments and/or use lightening agents (such as lead or titanium) to reduce production costs.