Much like etching a PCB, Blake started with a copper sheet, writing and drawing his works backwards with stopping varnish, an acid-resistant varnish that sticks around after a nitric acid bath.

The process involved looks to recover copper and nitric acid from copper nitrate, a common waste byproduct of processing metal. While a process called thermal decomposition exists to accomplish ...

Scratch tests and nitric acid tests will damage the item a bit ... Whether you're trying to determine if your copper hardware is real or fake or looking for fixtures of solid brass, make sure ...