Spectroscopic characteristics of human melanin in vivo.

In this paper we present the absorption characteristics of human melanin in the visible range of wavelengths and specifically in the range 620-720 nm. The spectroscopy of melanin is studied by measuring remittance spectra of normal skin and vitiligo-involved skin of volunteers-patients. It is assumed that the spectral differences between adjacent areas of normally pigmented skin, and to some degree amelanotic skin, can only be due to the variations of the melanin filter. The ratio of the remittance spectrum of the vitiligo-involved skin with the spectrum of the normal skin in the range 620-720 nm can be fitted with a straight line for all the volunteers. A very strong correlation is obtained between the intercept and the slope for all the volunteers, which leads us to conclude that it is indeed melanin that we are measuring in all the volunteers and that it is the same substance spectroscopically for all the volunteers.