As the thickest layer of the skin, the dermis can be found below the epidermis. It is made up of two parts, the papillary dermis and the reticular dermis. The upper dermis, or the papillary dermis, is where collagen fibers and connective tissue can be found. Below that is the reticular dermis. This is the deepest layer penetrated by needles used in tattooing, making it the deepest layer of the skin where the ink can be found. In order to achieve complete tattoo removal, wavelengths produced by lasers during laser tattoo removal have to penetrate the skin and reach the reticular dermis layer and break up the deepest ink particles.
Older laser technology used shorter wavelengths, which caused damage to the epidermis and often did not reach the reticular dermis. This caused hypopigmentation, or the discoloration of the skin caused by skin damage. In attempting to remove the ink pigment of a tattoo, these older lasers were also removing the pigment of the skin. Additionally, since they couldn’t reach the reticular dermis layer of the skin, tattoos would fade but complete removal wasn’t achieved.
Now, medical lasers create longer wavelengths to avoid damage to the epidermis, and are advanced enough to only target the dermis layer. This newer technology allows those who are more susceptible to hypopigmentation – those with tanned or darker skin – to receive laser tattoo removal treatments without fear of skin damage and discoloration.