About 15% of Americans have at least one tattoo, that's nearly 30 upper-school girls, but do any of them know exactly what they've done? Probably not. Tattoo machines push the ink under your skin to leave a permanent picture. The term “ink” however, is used loosely.
Tattoo ink is not really ink but actually dry pigment suspended in a carrier solution. This pigment usually comes from metal salts but is occasionally made from plastics. Unfortunately for the boy that had to have a glow-in-the-dark tattoo, pigments made from plastic tend to carry greater risks: plastic-based inks can lead to polymerization under the skin which means that the particles of the tattoo pigment join into a larger, solid piece under the skin. For pigments - plastic or metal - to work as a tattoo, they must be suspended in a carrier solution which keeps them evenly mixed, clean, and applicable. The carrier is most commonly made from ethyl alcohol in the form of vodka or Listerine mixed with glycerine and propylene glycol. However, just like the dry pigment, carrier solutions carry risks. Home-made and even some commercial solutions may contain anti-freeze, gluteraldehyde, and even formaldehyde which are all toxic. Even among the properly-made carriers, if an ethyl alcohol carrier reacts with the plastic storage bottle it can lead to polymerization under the skin. Upon reading this, many people are bound to wonder how on earth the government is allowing these chemicals to be used in tattoos but the truth is they don't allow it. In fact, they probably don't even know about it: tattoo pigments and inks are not regulated by the Food and Drug Administration and never have been. As many tattoo artists mix their own inks, some of the chemicals used may be mutagens, carcinogens, or toxins, or cause other reactions in the body which might not even show up for years.
With this information in mind, it seems important to mention that despite all these “risks”, tattoos have been around for thousands of years and are relatively safe. The oldest pigments came from grinding minerals and Carbon Black. The most common pigments today include said original mineral pigments as well as modern industrial organic pigments, a handful of vegetable-based pigments, and a few plastic-based pigments used mostly in alternative tattooing (glow-in-the-dark, black-light responsive, etc.) All pigments carry the risk of allergic reactions, scarring, and reactions from exposure to sunlight but some pigments are safer than others. Cobalt has been deemed too toxic for tattoo use and ultramarine is too unstable. The only safe blues and greens currently on the market are called Copper Pthalocyanine pigments and, like most metal-salt pigments, come from oxidizing metals and elements to produce a color change. Copper Pthalocyanine pigments actually are approved by the FDA for use in things such as paint for infant furniture, contact lenses, and surgical implants. Other safe pigments include black in the form of Carbon or Bone Black which comes from burning animal bones or kerosene and then gathering the soot. Many red pigments can cause serious skin damage such as burning or scarring, and rashes, especially those made from Iron Oxides and Mercury. Many doctors have actually directed patients to have the red pigment removed after biopsies were performed. Napthol Red is the safest known form of red pigment, and although Magenta is considered safe, it is more unstable and less lightfast than most other pigments. Oranges, Zinc and Titanium white, and even dioxazine/ carbazole purples and violets are considered safe. Even though Browns are usually based on Iron Oxides, they are generally considered safe as well. While yellow is not considered unsafe, high concentrations of the pigment may change the PH levels under the skin causing burns or scars which seems slightly unavoidable as cutting the pigment load leaves a more washed out and lighter hue.
Despite the popularity of tattoos, the risks seem to be more evident than the benefits. Another such risk is the substance used to clean skin before being inked. When getting a tattoo, the skin should be cleaned with a disinfectant such as Iodine, however many tattoo artists use Isopropyl Alcohol (rubbing alcohol). Rubbing Alcohol makes the skin more permeable so in cleaning the area, you are in fact helping any toxins in the ink get pushed into your skin faster and deeper.
Even with, or perhaps due to, all this information, it's difficult to say if tattooing is the fine art of chemistry or the chemistry of fine art. Either way, it goes to show you that science plays a big role in every aspect of life including entertainment.
