<P> In antiquity, the only engraving that could be carried out is evident in the shallow grooves found in some jewellery after the beginning of the 1st Millennium B.C. The majority of so - called engraved designs on ancient gold rings or other items were produced by chasing or sometimes a combination of lost - wax casting and chasing . </P> <P> In the European Middle Ages goldsmiths used engraving to decorate and inscribe metalwork . It is thought that they began to print impressions of their designs to record them . From this grew the engraving of copper printing plates to produce artistic images on paper, known as old master prints in Germany in the 1430s . Italy soon followed . Many early engravers came from a goldsmithing background . The first and greatest period of the engraving was from about 1470 to 1530, with such masters as Martin Schongauer, Albrecht Dürer, and Lucas van Leiden . </P> <P> Etching is the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio in the metal (the original process--in modern manufacturing other chemicals may be used on other types of material). As an intaglio method of printmaking it is, along with engraving, the most important technique for old master prints, and remains widely used today . </P> <P> Halftone is the reprographic technique that simulates ones it is continuous tone imagery through the use of equally spaced dots of varying size .' Halftone' can also be used to refer specifically to the image that is produced by this process . </P>

Mention any one characteristic feature of an offset press