Coppersmiths, historical artwork. Copper is a relatively soft metal, which means it can be worked and hammered into shape without heating. If extensive working of the metal is needed, heating followed by rapid cooling (quenching) is used. This process (annealing) ensures a uniform microscopic structure within the metal. Copper has been worked by humans for thousands of years. This artwork, a woodcut by German artist Sandrardt, is from the third edition of 'Les Entrailles de la Terre' (1902) by French author Eugene Caustier.