Fig. 1.

a A typical absorption spectrum, or apparent absorbance, of human melanin in vivo versus wavelength in nanometers. This was accomplished by calculating the logarithm (base e) of the ratio of the remitted intensity from vitiliginous to normal skin, at adjacent sites of the same volunteer. The straight line represents the best fit through the experimental points in the range 620–720 nm. The correlation coefficient for the straight line is 0.982 (Kollias and Baqer 1987). Reprinted from Journal of Investigative Dermatology, 89, Nikiforos Kollias, Ali H. Baqer, Absorption Mechanisms of Human Melanin in the Visible, 400–720 nm, 384–388, Copyright 1987, with permission from Elsevier. b Chemical structure of the eumelanin monomers 5,6-dihydroxyindole (DHI) (1) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) (2) (Watt et al. 2009)