Paper presents a study on the chromatic stability of the pigments and colors with certain mediums after a controlled laser irradiation (1064 nm). The present paper contains observations and conclusions about Nd:YAG laser limits of application on artwork polychromatic surface in concordance with laser beam parameters and colors composition. Main qualitative comments are based on reflection spectral measurements and trichromatic diagrams X, Y, Z in concordance with international norms CIE 1976 (CIELAB). Chromatic coordinates and color variations are calculated.