Imaging the antique: unexpected Egyptian blue in Raphael'sGalateaby non-invasive mapping

Unexpected finding of Egyptian blue emerged in Raphael's frescoTriumph of Galateaat Villa Farnesina, in Rome. This pigment is the oldest man-made blue, dating back to Egyptians who manufactured it first and whose occurrence was thought to be lost with Romans. Thanks to advanced imaging techniques it has been possible to non-invasively map its distribution throughout the frescoed surface and to obtain a non-invasive imaging stratigraphic analysis indicating whether pure painting layers, mixtures or overlapping occurred. Egyptian blue identification on Raphael'sGalateais so far the earliest of sixteenth century, and could be the first step towards its tracking in Renaissance, demonstrating that non-invasive techniques are a mandatory step not only for materials identification but also for understanding art history and its dynamics.