A new tool for painting diagnostics: Optical coherence tomography

Abstract

Non-destructive techniques have seen a successful growth in last few years and among them optical ones are widely diffused and extremely well received in the field of painting diagnostics because of their effectiveness and safety. At present, many techniques for non-destructive investigations of paintings are available, nevertheless none of them is suitable for a quantitative characterization of varnish. However, varnish removal, either partial or complete, is a fundamental part of the cleaning process which is an essential step in painting conservation. This critical process has been carried out, up to now, without the possibility of any non-destructive measurement for assessing the actual varnish thickness, but microscope observation of micro-detachment. Optical Coherence Tomography (OCT) is a non-invasive technique which is well-established for biomedical applications. In this work we present a novel application of OCT to measure the varnish film thickness for painting diagnostics.