In our present studies, the time-resolved emission spectrum of delayed luminescence of cell cultures of human fibroblast and human melanoma have been measured using a sophisticated single photon device. Noticeable differences have been found both in the emission spectra, which are time dependent, and in the timing aspects of the different spectral components. This powerful and noninvasive technique can be applied in all fields of skin research, such as the investigation of skin abnormalities and to test the effect of products involved in regeneration, antiaging, and UV-light protection in order to prevent skin cancer. (C) 2005 American Institute of Physics