Fine art painting characterization by spectroscopic ellipsometry: Preliminary measurements on varnish layers

Abstract

The long-term conservation of the original state of paintings requires high quality multi-spectral digital image technologies. CRISATEL Program addresses fine art professionals as primary end-users base. The analysis by spectroscopic ellipsometry of the varnish on fine art paintings will allow the curator to correct the effect of aged or glossy varnish on the digital images and to simulate the original state of the masterpiece through this superficial layer. Sets of varnish samples have been measured first at the University of Cyprus using a SOPRA GES5 Spectroscopic Ellipsometer and then at SOPRA facilities with a Fourier transform infrared spectroscopic ellipsometer. The capability to measure a varnish layer (thickness and optical index) on glass and to distinguish synthetic from natural varnishes has been proved. The goal of this paper is to review the first results obtained in the characterization of varnishes for fine art paintings, and to present some problems that are still open and can represent a challenging research field for the future. © 2004 Elsevier B.V. All rights reserved.