It seems like everybody is turning their bodies into artwork to express their feelings and ideas
Tattoos are fashionable right now! From simple black drawings to elaborate coloured designs, it seems like everybody is turning their bodies into artwork to express their feelings and ideas. However, for the chemistry-curious, it turns out there isnt much information available about the chemical composition of the dyes used. Not because this is impossible to determine, but because most ink recipes are trade secrets, protected for each manufacturer.
However, we at The Chemical Blog are an inquisitive bunch and decided to do a little digging about what is out there regarding tattoo dyes. The exact chemical composition may not always be explicit, but you can still have a pretty god idea of what is getting into your body, if you decide to get a tattoo.
What exactly are tattoo inks?
The oldest ink pigments used were simply grounded minerals of different colours, but todays tattoo artist has at his disposal a great variety of natural and synthetic pigments, even including pigments that glow in the dark or under ultraviolet light.
This is not the definitive answer, but most likely, tattoo inks include:
- synthetic metal salt pigments
- natural mineral pigments
- vegetable-based dyes
- plastic-based dyes
Chemistry of tattoo inks | |
| Colour | Compound |
| Black | Carbon (from combustion), wustite (rich in iron oxide, FeO), magnetite crystals |
| Brown | Ochre (rich in iron oxide and clay) |
| Red | Cinnabar (HgS), iron oxide (Fe2O3), Cadmium red (CdSe) |
| Orange | Cadmium seleno-sulphide, disasodiarylide, disazopyrazolone |
| Yellow | Cadmium yellow (CdZnS, CdS), ochre, curcuma yellow, chrome yellow (PbCrO4), disazodiarylide |
| Green | Malachite ([Cu2(CO3)(OH2)]), chromium oxide (Cr2O3), Cu/Al phthalocyanine, monoazo pigment, ferrocyanides |
| Blue | Cobalt blue, azure blue, azurite (rich in copper carbonate), lapis lazuli (rich in sodium aluminium silicate), Egyptian blue (rich in calcium copper silicate), copper phthalocyanine |
| Violet | Quinacridone, dioxazine, carbazole, manganese ammonium pyrophosphate |
| White | Lead carbonate (PbCO3), titanium dioxide (TiO2), barium sulphate (BaSO4) |
What about the carrier solution?
The carrier solution is used to keep the ink evenly distributed when applying, as well as keep it free from bacteria which may cause infections. Most common compounds used, alone or in combination, include:
Lack of regulation
Unfortunately, there is a serious lack of regulation concerning the chemicals used in this field, and every year there are many reports of adverse reactions to either the actual chemical used or contamination present. This may include, for example, infections, allergic reactions, nodules formed under the skin in response to the pigment used or extensive swelling and scarring.
According to an FDA fact sheet, although a number of colour additives are approved for use in cosmetics, none is approved for injection into the skin. Many pigments used in tattoo inks are not approved for skin contact at all. Some are industrial grade colours that are suitable for printers ink or automobile paint. Despite these cases, the FDA maintains it cannot keep any regulatory authority over the pigments used in tattooing, due to other competing public health priorities and a previous lack of evidence of safety problems specifically associated with these pigments.
Enter the chemists!
In the absence of governmental regulation, enter the chemists to save the day! Well, maybe not to save it, but at least to determine what exactly is in some tattoo dyes. In 2001, Anthony Timko and colleagues published a study in the Archives of Dermatology investigating the chemical composition of tattoo pigments by using x-ray microanalysis by energy-dispersive spectrometry (EDS). The team was able to identify oxygen (73%), titanium dioxide (67%) and carbon (67%) as the most common compounds, but this varied greatly between products, even for the same colour. It turned out that this analysis followed closely the MSDS sheets obtained from the manufacturers, with only a few exceptions. Interestingly, there werent any missing elements from the MSDS sheets, but on the contrary, the researchers failed to detect some of the elements mentioned.
Removable tattoos
A recent trend in the tattoo arena involves the use removable inks (please note these are different from temporary tattoos, which fade after a few days). These have an entirely different approach, as they can be degraded by the body when the user decide he (or she) no longer wants it. In this case, the dye is wrapped in a plastic capsule (made of poly(methyl methacrylate, or PMMA) that protects it and keeps it in place until the owner decides its time for the tattoo to go.
By treating the tattooed area with an appropriate laser, the light breaks the capsule, and the released ink is easily absorbed by the bodys immune system. The tattoo disappears within a few days. This technology was initially developed in the US by Bruce Klitzman and Kim Koger, for which they were granted the first patent for tattoo inks. It has been further developed, and is becoming increasingly more available.
And there you have it! Everything we could find about the chemical composition of tattoo inks. This may be useful if youre trying to convince somebody not to have a tattoo or simply to prepare yourself to ask the right questions to your tattoo artist.
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