Fluorescence Lifetime Imaging


Fluorescence Lifetime Imaging (FLIM) is based on the acquisition of a series of images from the surface of a painting at different temporal delays following excitation using a pulsed laser source. The technique was established for the analysis of works of art and has been applied in the past for the study of Michelangelo’s David and paintings by Masolino di Panicale and Van Gogh by IFN-CNR and the Politecnico di Milano. Fluorescence emissions have characteristic wavelengths and lifetime. FLIM records the intensity of fluorescence at different times, and analysis of data yields images of the fluorescence lifetime. These analytical images of a painted surface may allow the assessment of differences in the emission properties (and hence composition) of pigments and binding media present on the surface. Various examples of organic and inorganic pigments which have specific fluorescence lifetimes have been published. The real strength of the technique is the power to detect differences in emissions from complex surfaces – for example the detection of long-lived luminescence emissions from a painting on paper by Van Gogh which is attributed to semiconductor pigments. Within the FUTURHAMA project, FLIM is being used for the analysis of selected paintings and will contribute to establishing areas for further specific non-invasive analysis using complementary techniques. In addition, FLIM will be combined with microscopic analysis for the examination of pigments and fragments to detect heterogeneities in samples, and the presence of multiple or different luminescent materials.

Bibliographical References:

COMELLI D., NEVIN A., BRAMBILLA A., OSTICIOLI I., VALENTINI G., TONIOLO L., FRATELLI M., CUBEDDU R (2012). On the discovery of an unusual luminescent pigment in Van Gogh’s painting “Les bretonnes et le pardon de pont Aven”. APPLIED PHYSICS. A, MATERIALS SCIENCE & PROCESSING, vol. 106, p. 25-34, ISSN: 0947-8396, doi: 10.1007/s00339-011-6665-9.