Macro X-ray fluorescence imaging spectroscopy of the suggested Santi di Tito's portrait of Galileo Galilei

A painting of a bearded man on display at the Eremitani Museum in Padua that hasbeen attributed to Jacopo Tintoretto has been suggested to be the lost portrait ofGalileo Galilei painted by the Tuscan master Santi di Tito in 1602. Here, we presentthe X-ray fluorescence (XRF) imaging spectroscopy of the painting in a search forelements that could help authenticate it. The XRF analysis demonstrated a typicalpalette of the 16th century consistent with both painters. However, the study demon-strated that the sitter had reddish hair and wore a coat that could be a gown. Theoriginal color of the eyes is not the present brown of the work, squaring with thelight blue of Galileo's eyes in other portraits. There was a vermilion concentrationunder the left eye near a characteristic nevus on Galileo's face. This feature is inthe copy of Santi di Tito's painting engraved by Giuseppe Calendi at the end of the18th century, and thus consistent with evidence supporting the identity of the sitteras Galileo.