Fifteenth century Florentine mural investigated in situ with VNIR Hyperspectral Imaging and NIR Photography supports interpretation as a bloodletting scene

Abstract This study provides new data which suggest a novel interpretative hypothesis not only on the specific painting, but on the use of bloodletting as medical practice in the Florentine Quattrocento. As a part of a cycle of frescoes devoted to the Seven Corporal Works of Mercy, the examined lunette depicts the “Visit to the sick” in a domestic interior, but it has never been considered as an historical document of precise medical practices. The scene’s definitive interpretation is still unresolved because of the uncertainty of some iconographic details. A campaign of in-situ and non-invasive technical investigations was performed to retrieve possible traces of previous details today concealed. The technical solutions adopted to implement the measurements campaign are illustrated, as an experimental example for remote sensing inspection of mural paintings in-situ. The position of the painting high up on a wall of an historical venue led to opting for stand-alone optical imaging techniques which could operate in remote sensing mode. By combining the use of portable Hyperspectral Imaging with Near Infrared photography a set of detailed images could be obtained that highlighted details not otherwise detectable. Focused on the objects held by the persons present, the analysis of the mural of Visit of the Buonomini in her Lying in Bed , the gift of swaddling cloth could be a tourniquet, shadows of folds of a blanket a thumb lancet, and an object held a blood collection bowl, supported the hypothesis that it could be a medieval bloodletting scene.