To make it pliable, the copper is annealed after it is drawn to make it much less brittle and more pliable, so it is simpler to work with. His work within the 1850s on photograph-mechanical reproduction led to the creation of the photoglyphic engraving process, the precursor to photogravure. The primary picture is a reproduction of a 17th century Dutch engraving displaying a man leading a horse.