Niello

Niello is a metalworking and decorative technique in which a design is engraved into the surface of a silver, gold, or bronze object, and the engraved lines are then filled with niello, a black metallic alloy typically of sulfur combined with silver, copper, and lead, that is melted into the grooves and, once the surface is polished smooth, leaves a permanent, high-contrast dark line describing the design against the bright metal ground. Used since antiquity in the Mediterranean world and widely in medieval and Renaissance European metalwork and jewelry, niello engraving is also historically significant as a technical ancestor of intaglio printmaking, since Renaissance goldsmiths, including Maso Finiguerra, are traditionally credited with taking inked impressions from niello plates before the metal was filled, a practice understood as an early step toward the engraved print.