Tattoo Machines
Some tribal cultures traditionally created tattoos by cutting designs into the skin and rubbing the resulting wound with ink, ashes or other agents; some cultures continue this practice, which may be an adjunct to scarification. Some cultures create tattooed marks by hand-tapping the ink into the skin using sharpened sticks or animal bones or, in modern times, needles. Traditional Japanese tattoos (irezumi) are still “hand-poked,” that is, the ink is inserted beneath the skin using non-electrical, hand-made and hand held tools with needles of sharpened bamboo or steel.
The most common method of tattooing in modern times is the electric tattoo machine, which inserts ink into the skin via a group of needles that are soldered onto a bar, which is attached to an oscillating unit. The unit rapidly and repeatedly drives the needles in and out of the skin, usually 80 to 150 times a second.
The modern electric tattoo machine is far removed from the machine invented by Samuel O’Reilly in 1891. O’Reilly’s machine was based on the rotary technology of the electric engraving device invented by Thomas Edison. Modern tattoo machines use electromagnetic coils. The first coil machine was patented by Thomas Riley in London, 1891 using a single coil. The first twin coil machine, the predecessor of the modern configuration, was invented by another Englishman, Alfred Charles South of London, in 1899.
“Natural” tattoos
According to George Orwell, workers in coal mines would develop characteristic tattoos owing to coal dust getting into wounds. This can also occur with substances like gunpowder. Similarly, a traumatic tattoo occurs when a substance such as asphalt is rubbed into a wound as the result of some kind of accident or trauma. These are particularly difficult to remove as they tend to be spread across several different layers of skin, and scarring or permanent discoloration is almost unavoidable depending on the location. In addition, tattooing of the gingiva from implantation of amalgam particles during dental filling placement and removal is possible and not uncommon.
Dyes and pigments
A wide range of dyes and pigments can be used in tattoos, from inorganic materials like titanium dioxide and iron oxides to carbon black, azo dyes, and acridine, quinoline, phthalocyanine and naphthol derivates, dyes made from ash, and other mixtures.
Iron oxide pigments are used in greater extent in cosmetic tattooing. Many pigments were found to be used in a survey of professional tattooists. Recently, a blacklight-reactive tattoo ink using PMMA microcapsules has surfaced. The technical name is BIOMETRIX System-1000, and is marketed under the name “Chameleon Tattoo Ink”.
