The characterization of opaque color samples using reflected light is demonstrated with a computer screen photo-assisted technique (CSPT). CSPT utilizes standard computer screens as light sources and conventional web cameras as detectors to perform colorimetric or fluorescent evaluations that retain key spectral features of the tested substances. In this work, the fingerprinting of samples spectral reflectances is achieved by evaluating the reflected light under controlled computer screen illumination. Two different methods for processing of features are investigated, revealing complementary properties for classifications purposes. The attainable classification enables to distinguish different colors from just hues of a same color. © 2004 Elsevier B.V. All rights reserved.