S. Ignazio Loyola by Alessandro Mochetti (ca. 1760 - ca. 1812). Engraving on paper. Georgetown University Art Collection; Booth Family Center for Special Collections.
This copperplate engraving had a strong printing impression with a deep plate mark, but overall discoloration and particularly heavy foxing within the plate mark distracted viewers’ eyes from the aesthetics of the portrait. Conservators treated the print aqueously to reduce the soluble degradation products in the paper. In addition, they alkalized the print to reduce acidity, and they flattened the image to remove a hard crease caused by the bottom right corner being folded over in the past.