Luminescence from pigments and resins for oil paintings induced by laser excitation

The present work reports results of an extensive study of laser induced luminescence by tripled Nd:YAG laser (?=355 nm) of a few most common painting materials, namely, natural and synthetic pigments and resins. The luminescence spectra have been analyzed by an Optical Multichannel Analyzer (OMA III). Luminescence time decay has been measured by a Streak camera or by the OMA III. Pigments and resins show characteristic emission spectra with bands peaking in the visible. The decay ranges from less than 1 ns up to 700 ?s for pigments and for resins. The mechanism of excitation and relaxation leading to luminescence is discussed for the various materials. Oil colour specimens have been irradiated by a UV KrF laser (?=248 nm). Luminescence photographs have been detected by an intensified charge coupled device (ICCD) camera at different time delays.