Etching is a printmaking technique where acid cuts into a metal plate to create an image, but its roots stretch back to ancient times—etched carnelian beads from the Indus Valley civilization (3rd millennium BCE) were traded as far as Mesopotamia and Egypt. The modern process involves coating a plate (copper, zinc, or steel) with acid-resistant wax, scratching a design into it, and then "biting" the exposed lines with acid before inking and printing through a high-pressure press. While the technique was perfected by goldsmiths for decorating armor, Daniel Hopfer of Augsburg (c. 1470–1536) is credited with inventing it as a printmaking method around 1500. Masters like Rembrandt and Francisco Goya famously combined etching with other intaglio techniques such as engraving and aquatint to create expressive, layered artworks. Beyond fine art, etching is now a crucial technology in modern manufacturing, used for microfabrication and etching circuit boards, proving its evolution from a manual craft to a pillar of the digital age.