A methodological approach to study the stability of selected watercolours for painting reintegration, through reflectance spectrophotometry, Fourier transform infrared spectroscopy and hyperspectral imaging

Claudia Pelosi; Giuseppe Capobianco; Giorgia Agresti; Giuseppe Bonifazi; Fabio Morresi; Sara Rossi; Ulderico Santamaria; Silvia Serranti

doi:10.1016/j.saa.2018.03.008

A methodological approach to study the stability of selected watercolours for painting reintegration, through reflectance spectrophotometry, Fourier transform infrared spectroscopy and hyperspectral imaging

Spectrochim Acta A Mol Biomol Spectrosc. 2018 Jun 5:198:92-106. doi: 10.1016/j.saa.2018.03.008. Epub 2018 Mar 5.

Authors

Claudia Pelosi¹, Giuseppe Capobianco², Giorgia Agresti³, Giuseppe Bonifazi², Fabio Morresi⁴, Sara Rossi³, Ulderico Santamaria⁵, Silvia Serranti²

Affiliations

¹ Department of Economics, Engineering, Society and Business Organization, Laboratory of Diagnostics and Materials Science, University of Tuscia, Largo dell'Università, 01100 Viterbo, Italy. Electronic address: pelosi@unitus.it.
² Department of Chemical Engineering Materials & Environment, Sapienza, Rome University, Via Eudossiana 18, 00184 Rome, Italy.
³ Department of Economics, Engineering, Society and Business Organization, Laboratory of Diagnostics and Materials Science, University of Tuscia, Largo dell'Università, 01100 Viterbo, Italy.
⁴ Laboratory of Diagnostics for Conservation and Restoration, Vatican Museums, 001100 Vatican City, Vatican City State.
⁵ Department of Economics, Engineering, Society and Business Organization, Laboratory of Diagnostics and Materials Science, University of Tuscia, Largo dell'Università, 01100 Viterbo, Italy; Laboratory of Diagnostics for Conservation and Restoration, Vatican Museums, 001100 Vatican City, Vatican City State.

PMID: 29524748
DOI: 10.1016/j.saa.2018.03.008

Abstract

The aim of this work is to investigate the stability to simulated solar radiation of some paintings samples through a new methodological approach adopting non-invasive spectroscopic techniques. In particular, commercial watercolours and iron oxide based pigments were used, these last ones being prepared for the experimental by gum Arabic in order to propose a possible substitute for traditional reintegration materials. Reflectance spectrophotometry in the visible range and Hyperspectral Imaging in the short wave infrared were chosen as non-invasive techniques for evaluation the stability to irradiation of the chosen pigments. These were studied before and after artificial ageing procedure performed in Solar Box chamber under controlled conditions. Data were treated and elaborated in order to evaluate the sensitivity of the chosen techniques in identifying the variations on paint layers, induced by photo-degradation, before they could be observed by eye. Furthermore a supervised classification method for monitoring the painted surface changes adopting a multivariate approach was successfully applied.

Keywords: Fourier transform infrared spectroscopy; Hyperspectral imaging; Multivariate analysis; Reflectance spectrophotometry; Watercolours stability monitoring.