Methods and devices are disclosed for calibrating intensity of a light source in a system of evaluating a skin lesion using Elastic-Scattering Spectroscopy (ESS). The ESS system may illuminate a sample of the skin lesion with a pulse from the light source adjusted to a high output setting, receive a signal comprising an elastic scattering spectrum from illuminating the skin lesion sample at the high output setting, determine whether the received signal has an intensity that is greater than a saturation threshold associated with at least one optical detection sensor, and if so, store the elastic scattering spectrum from illuminating the skin lesion sample at the high output setting. If not greater than the saturation threshold, the ESS system may illuminate the skin lesion sample with a pulse from the light source adjusted to a low output setting, receive a signal comprising an elastic scattering spectrum from illuminating the skin lesion sample at the low output setting, and store the elastic scattering spectrum from illuminating the skin lesion sample at the low output setting.