 His monogram, used only on eleven of his chiaroscuro prints, consists in its fullest form of his initials "Io V" between two diagonally crossed pilgrim's staves, with a flower in the centre, on a cartellino or plaque, a style copied from Albrecht Dürer.His prints, recognised as a group, remained unattributed to any documented artist until 1851, when his name on the title page of a book he illustrated was connected with the monogram and the few documentary records.A similar monogram was used by the glass-painter Jacob Wechtlin, perhaps a brother.