Tattoos used to be done manually — that is, the tattoo artist would puncture the skin with a needle and inject the ink by hand. Though this process is still used in some parts of the world, most tattoo shops use a tattoo machine these days. A tattoo machine is a handheld electric instrument that uses a tube and needle system. On one end is a sterilized needle, which is attached to tubes that contain ink. A foot switch is used to turn on the machine, which moves the needle in and out while driving the ink about 1/16 inch or less (about 1 millimeter) into your skin.
Most tattoo artists know how deep to drive the needle into your skin, but not going deep enough will produce a ragged tattoo, and going too deep can cause bleeding and intense pain. Getting a tattoo can take about 15 minutes to several hours, depending on the size and design chosen.