Imaging, spectroscopic and sample analysis of a 16th century canvas painting representing the Holy Trinity with Saints

Abstract

This contribution focuses the attention on the documentation and diagnostic campaign on a 16th century canvas painting representing The Holy Trinity with the Saints Lawrence and Famiano, performed on the occasion of the restoration work carried out in the Laboratory of the master degree course in Conservation and Restoration of Cultural Heritage at University of Tuscia. The diagnostic investigation started with the documentation and non-invasive analysis through multispectral imaging and X-ray fluorescence spectroscopy respectively. After this first non-invasive step, micro-samples were taken for laboratory analysis through micro-stratigraphic inspection of cross-sections and morphological observation of canvas fibres. The results of the analysis, useful for the restoration work, highlighted the presence of a wide variety of pigments such as smalt blue, azurite, vermilion, lead white, lead and tin yellow, red and yellow ochre. Moreover, the ultraviolet fluorescence image showed the presence of an intense red fluorescence on the God garment, suggesting the use of an organic dye that was characterized through surface enhanced Raman spectroscopy. The most interesting result, revealed by infrared reflectography, was the reading of an inscription which allowed to redefine the dating of the painting with respect to that established by the stylistic and documentary analysis alone.