Optical and spectroscopic tools for evaluating Er:YAG laser removal of shellac varnish
Authors: Striova J., Salvadori B., Fontana R., Sansonetti A., Barucci M., Pampaloni E., Marconi E., Pezzati L., Colombini M.P.
Autors Affiliation: National Institute of Optics/CNR, florence, Italy;
Institute for Conservation and Valorization of Cultural Heritage/CNR, Sesto Fiorentino (FI) and Milan, Italy;
University of Florence, Florence, Italy
Abstract: We report on tests to remove naturally and artificially aged shellac varnish by laser and traditional chemical cleaning from the substrates of mural paintings. Optical tools were used for the evaluation of cleaning processes, in particular laser microprofilometry to assess the changes in the surface morphology and time-domain confocal optical coherence tomography (OCT) to evaluate varnish thickness. The cleaning assessment was integrated with molecular characterization provided by portable Fourier transform infrared spectroscopy operating in reflectance mode, and colorimetric measurements. This complete analytical approach led to optimized laser-based cleaning tests at 1.9 and 2.6 J/cm(2) in the presence of isopropanol, which ensured controllable and safe partial removal of shellac varnish without alteration to the substrate morphology.
Journal/Review: STUDIES IN CONSERVATION
Volume: 60 Pages from: S91 to: S96
KeyWords: Cleaning; Erbium; Fourier series; Fourier transform infrared spectroscopy; Optical tomography; Substrates; Tomography; Varnish, Analytical approach; Colorimetric measurement; Er: YAG; FTIR; Molecular characterization; Mural paintings; Shellac; Substrate morphologies, Chemical cleaningDOI: 10.1179/0039363015Z.000000000213Citations: 10data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2020-08-02References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here