Niello is an ancient metalworking technique where black or dark-colored alloys are filled into engraved lines on metal objects, typically silver or gold. The most common alloy for niello is a mixture of silver, copper, lead, and sulfur.
Here's how it works:
1. Engraving: A design is engraved into the metal surface.
2. Niello application: The niello paste is applied to the engraved lines.
3. Heating: The piece is heated, causing the niello to melt and flow into the engravings.
4. Polishing: The excess niello is polished away, leaving the design filled with the black alloy.
Niello was a popular technique in ancient Egypt, Greece, and Rome, and it experienced a revival during the Renaissance.