The result may be a decorative piece in itself , as when silver , gold or steel are engraved , or may provide a printing plate of copper or another metal , for printing images on paper which are also called engravings . The result may be a decorated object in itself , as when silver , gold , steel , or glass are engraved , or may provide an intaglio printing plate , of copper or another metal , for printing images on paper as prints or illustrations ; these images are also called engravings .