The following study is an attempt to identify pigments used in Byzantine and Postbyzantine painting, using optical microscopy combined with image- processing techniques, in both the visible and infrared spectra (380-1200 nm). The important step for the methodology of this study is the grey level measurements of standard reference samples of pigments (titanium white, lead red, English red, yellow ochre, burned sienna, malachite, verdigris, copper green, green earth, cobalt blue, ultramarine light, indigo, ivory black), suitably prepared for examination through an optical (metallographic) microscope in both visible and infrared spectra. The images recorded by an infrared CCD camera, sensitive up to1200 nm, were put through the digital image analysis software (Image Pro Plus program) and after several settings (as brightness and contrast), grey level measure¬ments were obtained. It should be noted that the basic stage in the measurement procedure is the creation of a reference grey scale, in order to calibrate the given measurements, so that the final results are comparable and can be reproduced. There are two separate measurements for each sample - one using the visible and one using the infrared spectrum - and the data wfere plotted against the measurements of reflectance of the same sample pigments, taken for reasons of initial reference with a spectrophotometer. The results obtained showed that the methodology used for the measurement of reflectance in the visible area of the spectrum gave results comparable to those taken from a classic spectrophotometer. The infrared measurements showed greater deviations from the expected results, but these can be attributed to the non-specialized optical equipment that was used. The reports could be especially valuable taken from the infrared area of the spectrum because they constitute an additional element for identification.