The Calvary, c. 1520. Although recipes for etching iron and steel are recorded at least as early as 1400, scholars have been unable to show that armor designs were etched in Italy or Germany before the end of the 15th century. As early as 1500 iron plates were also used to make prints, probably first in Augsburg, Germany, in the workshop of Daniel Hopfer. Etching allows the artist to draw freely on the plate and so is less laborious than engraving. Because of the acid then available, only iron or steel plates could be used and these rusted. For this reason only a small number of etchings were made (including six by Albrecht D?rer) until about 1550, when the technical difficulties of using copper plates had been overcome.