title: Time-resolved fluorescence spectroscopy and imaging of proteinaceous binders used in paintings.
abstract: The differentiation of proteins commonly found as binding media in paintings is presented based on spectrally resolved and time-resolved laser-induced fluorescence (LIF) and total emission spectroscopy. Proteins from eggs and animal glue were analysed with pulsed laser excitation at 248 nm (KrF excimer) and 355 nm (third harmonic of Nd:YAG) for spectrally resolved measurements, and at 337 nm (N2) and 405 nm (N2 pumped dye laser) for spectrally resolved lifetime measurements and fluorescence lifetime imaging (FLIM). Total emission spectra of binding media are used for the interpretation of LIF spectra. Time-resolved techniques become decisive with excitation at longer wavelengths as fluorescence lifetime permits the discrimination amongst binding media, despite minimal spectral differences; spectrally resolved measurements of fluorescence lifetime have maximum differences between the binding media examined using excitation at 337 nm, with maximum observed fluorescence at 410 nm. FLIM, which measures the average lifetime of the emissions detected, can also differentiate between media, is non-invasive and is potentially advantageous for the analysis of paintings.
authors.affiliation: Institute of Electronic Structure and Laser, Foundation for Research and Technology Hellas (IESL-FORTH), P. O. Box 1385, Heraklion, 71110, Crete, Greece. austin.nevin@courtauld.ac.uk
authors.forename: Austin
authors.initials: A
authors.lastname: Nevin
authors.forename: Daniela
authors.initials: D
authors.lastname: Comelli
authors.forename: Gianluca
authors.initials: G
authors.lastname: Valentini
authors.forename: Demetrios
authors.initials: D
authors.lastname: Anglos
authors.forename: Aviva
authors.initials: A
authors.lastname: Burnstock
authors.forename: Sharon
authors.initials: S
authors.lastname: Cather
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Cubeddu
mesh_terms: D049691:History, Medieval; D010150:Paint / Q000032:analysis; D010151:Paintings / Q000266:history*; D011506:Proteins / Q000032:analysis*; D013050:Spectrometry, Fluorescence
chemical_list: D011506:Proteins