On Devotional Artworks: A Non-Invasive Characterization of Pigments of the Madonna della Croce Wall Painting in Triggiano (Bari, Southern Italy)

Devotional artworks represent a valuable form of art, as they are evidence of religious worship and the demo-ethno-anthropological, as well as historical-artistic, heritage of a community, which is why they definitely belong to the cultural identity of a geographic area. The Madonna della Croce wall painting is an example of devotional art preserved today in the homonymous church in Triggiano (Bari, Italy). The presented study concerns the characterization of pigments used in the painting. The identification of pictorial materials had the aim of providing a contribution to knowledge about the painting, the history of restorations, and other historical events, and to increase the information about the Apulian painting to better reconstruct the social, cultural, and economic contexts of the region. Through a non-invasive and fast methodological approach, including portable digital microscopy, colorimetry, fibre optic reflectance spectroscopy (FORS), and X-ray fluorescence spectroscopy (XRF); 42 points considered on coloured areas were analysed in situ, and results on pigment identification were achieved. According to the local wall painting tradition, red and yellow ochres, green earth, vine black, massicot, and lead-tin yellow were found. Furthermore, both indigo- woad dye and a mixture of vine black and yellow ochre to obtain a blueish colour on the Virgin’s mantle were highlighted.