Print In the printing, a copper plate was used for phot […]
In the printing, a copper plate was used for photoengraving. The surface-polished copper plate was sensitized with a photosensitive emulsion and photographed thereon. The photosensitive copper plate needs to be heated to harden the glue. To avoid softening by heat, copper often contains a small amount of silver or arsenic to increase the softening temperature. Then, the plate is etched to form a printed surface on which the uneven pattern is distributed.
On the automatic typewriter, the layout is made by the arrangement of brass font blocks, which is another important use of copper in printing. Font blocks are usually made of leaded brass, sometimes with copper or bronze.