A tattoo is a puncture wound, made deep in your skin, that's filled with ink.

A tattoo is a puncture wound, made deep in your skin, that's filled with ink. It's made by penetrating your skin with a needle and injecting ink into the area, usually creating some sort of design. What makes tattoos so long-lasting is they're so deep — the ink isn't injected into the epidermis (the top layer of skin that you continue to produce and shed throughout your lifetime). Instead, the ink is injected into the dermis, which is the second, deeper layer of skin. Dermis cells are very stable, so the tattoo is practically permanent.


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.