Plate mark on the corner of an intaglio print - RIT Image Permanence Institute

A double plate mark - Luisa Feiersinger, Techne

loyola-after.avif

Plate mark on "S. Ignazio Loyola" by Alessandro Mochetti (ca. 1760 - ca. 1812). Engraving on paper - Georgetown University Art Collection; Booth Family Center for Special Collections