Non-invasive spectroscopic study of 19th century artists’ materials

In recent years, several studies have been conducted on 19th century works of art mainly from a cognitive or conservation point of view. Paintings of that period were usually made with new, as opposed to non traditional, pigments, a result of the fast development of chemical manufacturing processes. As a consequence, it can be particularly difficult to retrieve information needed to plan effective interventions for the proper conservation of these objects due to the lack of knowledge of the original materials used. The goal of this thesis is to provide information on 19th century painting materials, mainly pigments and dyes, through the spectroscopic study of works of art, by analysing laboratory mock-ups expressly prepared, and by analysing original pigments (in this specific case watercolours). The investigation of works of art and precious objects often present problems due to necessity of non destructive examination techniques. However, noninvasive analysis usually provides less information than that achievable by sampling. In order to improve the results obtainable with noninvasive investigations, a multidisciplinary approach based on the data's complementarities must be developed. In this thesis, point by point spectroscopic information using Fibre Optics Reflectance Spectroscopy (FORS) was integrated with High Hyperspectral Image Spectroscopy (HHIS) and, in a few selected cases, X-ray Fluorescence (XRF) spectroscopy, to better frame the case studies.