Multianalytical Study of a Painting on Copper

The painting studied, featuring the Virgin contemplating the sleeping Child, is a well known composition in the religious context, especially popular since the 16th century. The technique, oil on copper plate, and materials were examined applying a multimethodological non-invasive approach. The main goal was to quantitatively characterize the layer composition and thickness. To obtain them, X-ray fluorescence spectroscopy coupled with Monte Carlo simulation was used for the first time, to the best of our knowledge, for this kind of object. This technique was also integrated with more conventional photographic and spectroscopic techniques such as multiband imaging (MBI), Raman spectroscopy, external reflection Fourier transform infrared spectroscopy (ER FT-IR), and optical microscopy. The obtained data showed the use of a background based on lead white, a wide palette, which includes azurite, vermilion, lead white, and some ochers, and documented the conservation status. Although the investigations contended with the object's complexity, the results demonstrate the efficacy of the XRF-Monte Carlo simulation approach in characterizing the materials constituting the artwork in a totally non-invasive way.