How do tattoos work? A tattoo is a form of body modification where a design is made by inserting ink, dyes and pigments, either permanent or temporary, into the dermis layer of the skin to change the pigment. Different techniques are used to insert the ink, including dermagraphism, auto-dermal puncture, dermabrasion, subdermal implantation and digital implantation. Colors used in tattoos include red, black, brown, grey, blue, purple, pink and green. Some of the oldest forms of tattooing are called `cicatrization' and include cutting, scratching or rubbing the skin to produce a design. The word tattoo is believed to have originated from the Tahitian "tatu" which means `to mark something'. The oldest evidence of tattoos comes from Africa, when in 1391 BC mummy Otzi, was found. Tattooing has been practiced across the globe since ancient times – by early indigenous cultures as well as more modern societies – for a variety of reasons including religious rites, cultural traditions, aesthetic enhancement, personal expression or Tattooing has been around since ancient times, with many different forms of tattoos being used throughout history. One example can be seen in the two Ötzi mummies, from 3300 BC, who had dark lines etched into their skin. In modern times tattooing has become a popular form of art around the world, with an estimated 30% of people in the US aged between 16 and 70 having at least one tattoo.