Tattoos can be professional, amateur or accidental, as in the case of coal miners getting dust in their wounds. Many amateur tattoos come from prison, though some are related to gangs. Professional tattoos have many different subsets.
Professional tattoos can be related to culture, medicine or cosmetics. Many cultures, such as Samoans and Maori, use tattooing as a ritual act. People also get tattoos in case of medical emergencies to ensure that the correct medication or instruments get used. Tattoos are also used as locators for repeated applications of radiotherapy. Tattooing is sometimes used on the face to replace makeup or to correct uneven skin pigmentation.
About.com describes five types of tattoos. One is the grayscale tattoo, which is done all in black, sometimes with shading in gray. Another is the Asian-inspired tattoo. These include cherry blossoms, koi fish and Oriental tigers. Tribal tattoos are meant to resemble the cultural tattoos, though anyone can get them. Classic tattoos are those such as anchors and pinup girls that reference the types of tattoos popular in earlier days. Biomechanical tattoos are the opposite; they are meant to look very modern and display depictions of flesh and machinery meshing.
According to SkinDeepinArt.com, other types of popular tattoos include photorealistic, which look like photos, Celtic and caricature.