Tattoo ink

Tattoo inks consist of pigments combined with a carrier, and are used in tattooing.

Tattoo inks are available in a range of colors that can be thinned or mixed together to produce other colors and shades. Most professional tattoo artists purchase inks pre-made (known as pre-dispersed inks), while some tattooers mix their own using a dry pigment and a carrier.
Tattoo ink is generally permanent. Tattoo removal is difficult, painful, and the degree of success depends on the materials used. A recently developed ink InfinitInk is comparatively easy to remove. Unsubstantiated claims have been made that some inks fade over time, yielding a "semi-permanent tattoo."
In the United States, tattoo inks are classified as a cosmetic or color additive, and is thus subject to regulation by the U.S. Food and Drug Administration (FDA);Some tattoo parlors have incorrectly claimed that their inks have such an approval.Although the pigments are not regulated, the FDA and medical practitioners have noted that many ink pigments used in tattoos are “industrial strength colors suitable for printers’ ink or automobile paint.”
In California, Proposition 65 requires that Californians be warned before exposure to certain harmful chemicals; tattoo parlors in California must warn their patrons that tattoo inks contain heavy metals known to cause cancer, birth defects, and other reproductive harm.
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.[6] 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.
A carrier acts as a solvent for the pigment, to “carry” the pigment from the point of needle trauma to the surrounding dermis. Carriers keep the ink evenly mixed and free from pathogens, and aid application. The most typical solvent is ethyl alcohol or water, but denatured alcohols, methanol, rubbing alcohol, propylene glycol, and glycerine are also used. When an alcohol is used as part of the carrier base in tattoo ink or to disinfect the skin before application of the tattoo, it increases the skin's permeability, helping to transport more chemicals into the bloodstream.
A variety of medical problems, though uncommon, can result from tattooing.

Medical workers have observed rare but severe medical complications from tattoo pigments in the body,and have noted that people acquiring tattoos rarely assess health risks prior to receiving their tattoos.