That's where the macrophages, the cells Henri studied, come in. They're specialized immune cells — their name means big eater in Greek — and their job is to slurp up interlopers, says Klitzman. "Macrophages can basically swallow many, many tattoo pigment particles, almost like a vacuum cleaner, just go along and suck up all those particles," he says.
Modern Japanese tattoos are real works of art, with many modern practioners, while the highly skilled tattooists of Samoa continue to create their art as it was carried out in ancient times, prior to the invention of modern tattooing equipment. Various cultures throughout Africa also employ tattoos, including the fine dots on the faces of Berber women in Algeria, the elaborate facial tattoos of Wodabe men in Niger and the small crosses on the inner forearms which mark Egypt's Christian Copts.
Despite all our advances in technology, the basic needling technique used to insert pigment into skin hasn’t changed all that much over time. The biggest change came when the electric tattooing machine was first patented in 1891. That technology has remained relatively stagnant since–aside from prisoners’ ad hoc redesigns, in which a cassette recorder, an electric razor, or electric toothbrush can be used as a motor. These jailed tattooists’ inventions show just what desperate lengths people will go to to turn a boring patch of bare skin into something that better expresses the self underneath.
Half-sleeves or quarter-sleeves are tattoos that cover only part of an arm, usually above the elbow, but can also be found below the elbow. A sleeve implies complete tattoo coverage of a particular area, so a half sleeve is a tattoo that covers the entire upper or lower arm. A "quarter sleeve" usually covers the area of skin from the shoulder midway to the elbow.
The American Academy of Dermatology distinguishes five types of tattoos: traumatic tattoos, also called "natural tattoos", that result from injuries, especially asphalt from road injuries or pencil lead; amateur tattoos; professional tattoos, both via traditional methods and modern tattoo machines; cosmetic tattoos, also known as "permanent makeup"; and medical tattoos.