|Tattoo Ink Chemistry|
The short answer to the question is: You can't be 100% certain! Manufacturers of inks and pigments are not required to reveal the contents. A professional who mixes his or her own inks from dry pigments will be most likely to know the composition of the inks. However, the information is proprietary (trade secrets), so you may or may not get answers to questions.
Most tattoo inks technically aren't inks. They are composed of pigments that are suspended in a carrier solution. Contrary to popular belief, pigments usually are not vegetable dyes. Today's pigments primarily are metal salts. However, some pigments are plastics and there are probably some vegetable dyes too. The pigment provides the color of the tattoo. The purpose of the carrier is to disinfect the pigment suspension, keep it evenly mixed, and provide for ease of application.
Tattoos and Toxicity
This article is concerned primarily with the composition of the pigment and carrier molecules. However, there are important health risks associated with tattooing, both from the inherent toxicity of some of the substances involved and unhygienic practices. To learn more about the risks associated with a particular tattoo ink, check out the Material Safety Data Sheet (MSDS) for any pigment or carrier. The MSDS won't be able to identify all chemical reactions or risks associated with chemical interactions within the ink or the skin, but it will give some basic information about each component of the ink. Pigments and tattoo inks are not regulated by the US Food and Drug Administration. However, the Food and Drug Administration is examining tattoo inks to determine the chemical composition of the inks, learn how they react and break down in the body, how light and magnetism react with inks, and whether there are short- and long-term health hazards associated with ink formulations or methods of applying the tattoos.Tattoo Pigment Chemistry
The oldest pigments came from using ground up minerals and carbon black. Today's pigments include the original mineral pigments, modern industrial organic pigments, a few vegetable-based pigments, and some plastic-based pigments. Allergic reactions, scarring, phototoxic reactions (i.e., reaction from exposure to light, especially sunlight), and other adverse effects are possible with many pigments. The plastic-based pigments are very intensely colored, but many people have reported reactions to them. There are also pigments that glow in the dark or in response to black (ultraviolet) light. These pigments are notoriously risky - some may be safe, but others are radioactive or otherwise toxic.
Here's a table listing the colors of common pigments use in tattoo inks. It isn't exhaustive - pretty much anything that can be used as a pigment has been at some time. Also, many inks mix one or more pigment:
Iron Oxide (Fe3O4)
Iron Oxide (FeO)
Natural black pigment is made from magnetite
crystals, powdered jet, wustite, bone black,and amorphous carbon
from combustion (soot). Black pigment is commonly made into India ink.
Logwood is a heartwood extract from Haematoxylon campechisnum, found in Central America and the West Indies.
|Brown||Ochre||Ochre is composed of iron (ferric) oxides mixed with clay. Raw ochre is yellowish. When dehydrated through heating, ochre changes to a reddish color.|
Cadmium Red (CdSe)
Iron Oxide (Fe2O3)
|Iron oxide is also known as common rust. Cinnabar and cadmium pigments are highly toxic. Napthol reds are synthesized from Naptha. Fewer reactions have been reported with naphthol red than the other pigments, but all reds carry risks of allergic or other reactions.|
disazodiarylide and/or disazopyrazolone
|The organics are formed from the condensation of 2 monoazo pigment molecules. They are large molecules with good thermal stability and colorfastness.|
|Flesh||Ochres (iron oxides mixed with clay)|
Cadmium Yellow (CdS, CdZnS)
Chrome Yellow (PbCrO4, often mixed with PbS)
|Curcuma is derived from plants of the ginger family; aka tumeric or curcurmin. Reactions are commonly associated with yellow pigments, in part because more pigment is needed to achieve a bright color.|
Chromium Oxide (Cr2O3), called Casalis Green or Anadomis Green
Ferrocyanides and Ferricyanides
|The greens often include admixtures, such as potassium ferrocyanide (yellow or red) and ferric ferrocyanide (Prussian Blue)|
|Blue pigments from minerals include copper (II) carbonate (azurite), sodium aluminum silicate (lapis lazuli), calcium copper silicate (Egyptian Blue), other cobalt aluminum oxides and chromium oxides. The safest blues and greens are copper salts, such as copper pthalocyanine. Copper pthalocyanine pigments have FDA approval for use in infant furniture and toys and contact lenses. The copper-based pigments are considerably safer or more stable than cobalt or ultramarine pigments.|
Manganese Violet (manganese ammonium pyrophosphate)
Various aluminum salts
|Some of the purples, especially the bright magentas, are photoreactive and lose their color after prolonged exposure to light. Dioxazine and carbazole result in the most stable purple pigments.|
Lead White (Lead Carbonate)
Titanium dioxide (TiO2)
Barium Sulfate (BaSO4)
|Some white pigments are derived from anatase or rutile. White pigment may be used alone or to dilute the intensity of other pigments. Titanium oxides are one of the least reactive white pigments.|