How were antique prints and maps printed? A brief overview of printing methods
The purpose of printing has always been to make multiple exact copies of a given image, map or text. Different methods of printing have been developed over time to achieve this. The main techniques used to print antique maps and prints are as follows:
- Relief processes (woodblocks, wood cuts, wood engraving) – starting from a flat block or plate, the blank parts of the image are cut way from the plate leaving the design to be printed remaining in relief. The plate is then inked and applied to the paper under pressure to create the printed image or map.
- Intaglio processes (line engraving – steel engraving or copperplate, etching, aquatint, mezzotint, dry-point) – the design to be printed is cut or engraved into a metal plate using an engraver’s tool, or acid. The flat plate is covered in ink, and the excess ink is wiped away from the unengraved flat surface of the plate, but remains in the engraved grooves. The paper is applied to the inked plate under pressure, to create the printed design. The use of metal made the plate more durable than wood, allowing more prints to be created from a single plate before wear started to degrade the resulting prints.
- Surface processes (Lithography) – the design is drawn on a flat surface, usually stone, with a greasy substance. The plate is moistened, however due to the antipathy between oil and water, water is retained only by the ungreased parts of the plate. An oil-based ink is applied to the surface, but is repelled by the moist areas, sticking only to the originally greased surface. Finally, the inked design is transferred by applying the paper onto the surface.
Woodblock printing was the dominant method for printing maps and prints during the period 1450-1550. Copperplate printing was increasingly used to print maps from the middle of the 15th century. Steel engraving – which being a harder metal was more durable and allowed for greater image detail – started to become the dominant method for printing maps and finer prints from about 1825. Lithography was invented in 1796, but was not commonly used until about 1820, and was not mechanised until 1860, after which it became more widely adopted as a printing method. The most commonly used printing method today is offset printing, which was invented in 1875; it became the dominant printing method during the first decade of the 20th century. By around 1910 the earlier printing methods which had hitherto been used to make maps and prints had effectively died out.