Commercial manufacturers combine pigments with carriers such as ethyl alcohol or distilled water to create liquid inks.
[14] Titanium dioxide is slightly abrasive and can cause microscopic bits of nickel and chromium to wear off tattoo needles and get into the skin.
[16] Tattoo ink manufacturers often blend metal pigments and/or use lightening agents (such as lead or titanium) to reduce production costs.
[20][21] Glow-in-the-dark tattoo ink absorbs and retains light, and then glows in darkened conditions by process of phosphorescence.
[28] The world's oldest tattoos known to date, those of the Tyrolean Iceman known as Ötzi, were applied 5300 years ago with soot and/or ground charcoal based pigments.
[31] Some ink was made by combining soot and sugarcane juice, left to ferment for a short time to develop some alcohol.
[33] Inuit women have a tradition of kakiniit, tattoos historically made with qulliq lampblack[34] and seal suet.
[37] This ink is made with soot from burning particular woods, bound with animal glue, and the method of application results in a greenish black color in the skin.
[38][39] In amateur "stick and poke" tattoos done for amusement or as a hobby, people often use improvised ink, which adds risk of infection and scarring.
[27] Components of tattoo ink may cause allergic reactions in skin, including red, green, yellow and blue pigments.
[8] Many of the particles used in tattoo inks are less than 100 nanometers in diameter, making it easier for them to penetrate cells and possibly cause cancer.
[3] However, a review article in 2012 said "The number of skin cancers arising in tattoos is seemingly low, and this association has to be considered thus far as coincidental.
"[45] After application of a tattoo, a portion of the ink is carried away by blood vessels and the lymphatic system, and some of it may be excreted or stored elsewhere in the body.
[51][52] In rare cases, a person undergoing a magnetic resonance imaging (MRI) exam may feel temporary discomfort or irritation around tattoos made with iron oxide pigments.
[58] The FDA does not generally exercise this regulatory authority because of other higher priorities and insufficient evidence of specific color additives causing safety problems in tattoo ink.
[15] A judge ordered two of the companies to put warning labels on their products and in their catalogs to tell California customers that tattoo inks contain heavy metals known to cause cancer, birth defects, and other reproductive harm.
[17] People who continue to practice traditional tattooing methods and styles may make their own pigments or purchase manufactured ink.
[61] One of the oldest known examples of human tattooing is the 5,300-year-old ice mummy known as Ötzi, discovered in 1991 near the border between Austria and Italy.
[63] Found in southern Peru, in the Chiribaya cultural area, a 1000-year-old mummy of a woman showed decorative and symbolic tattoos made with soot and plant material.
[27] Sailor Jerry, who started working as a tattoo artist in the 1930s, mixed D&C dry color pigments (approved for use in drugs and cosmetics) with isopropyl alcohol and benzalkonium chloride.
[71] Anderson co-founded a company called Freedom-2 to bring the ink to market[72] with assistance from Edith Mathiowitz, Joshua Reineke and A. Peter Morello of Brown University.
[75] Mehndi body art involves applying henna dye externally to create a temporary tattoo on the surface of the skin, typically producing a brown color that fades in a few weeks.
Health Canada and the US FDA have advised against the use of "black henna" pigment that contains para-phenylenediamine (PPD), an ingredient in hair dyes.
[76][59] Allergic reactions to PPD include rashes, contact dermatitis, itching, blisters, open sores, scarring and other potentially harmful effects.
[78] This dye is derived from a Central and South American fruit (Genipa americana) traditionally used for a variety of purposes including medicine and body art.