Giambattista Tiepolo’ sons reproduced many of their father’s works in print. Perhaps this is why there are so few prints of his paintings by professional engravers. A stunning example is this virtuoso, hyper-realistic ‘portrait’ of Catherine of Siena. This 14th-century mystic identified with the suffering of the crucified Christ to such an extent that she received stigmata, wounds in her hands, in a vision.