Color Biophysics and the Human Color Perception in Relation to Pigments and Tattooed Skin

Perception of skin color in the natural state, or with tattoo pigment installed in the dermis is highly complex and includes both optical requisites and eye and brain functions connected to advanced cognitive and psychological functions. Permanent makeup (PMU) is miniaturized tattooing on critical anatomical location aiming at fulfilment of a person's esthetic ideal. It is a special challenge since a satisfactory outcome depends on perfectionated technique and very critical selection of pigments. The eye can be compared to a digital camera, and the center of central vision in the brain to a computer and color integrator. Color perception is the end product of a complicated brain function. The background theory of color physics and perception is reviewed with emphasis on aspects related to changed skin color created by pigment installed in the dermis with the purpose to tattoo eyebrows, eyeliners, lips, and other locations. The delicate dosing of pigment relative to the natural skin tone is highlighted. The review is relevant for all aspects of PMU including medical tattooing, e.g., areola tattooing after breast cancer surgery. A detailed guidance to PMU artists and medical tattooists on selection and use of tattoo inks and pigments is provided. The guidance is also relevant to laser surgeons and technicians performing tattoo removal.