Metal engraving History
metal engraving was introduced in 1792 by Jacob Perkins (1766–1849), an American inventor, for banknote printing. When Perkins moved to London in 1818, the technique was adapted in 1820 by Charles Warren and especially by Charles Heath (1785–1848) for Thomas Campbell’s Pleasures of Hope, which contained the first published plates engraved on steel. The new technique only partially replaced the other commercial techniques of that time such as woodcut, wood engraving, copper engraving and later lithography.
Process of Metal Engraving
Confusingly, the printmaking technique used in Metal engravings is, after the earliest years in the 1820s, normally a combination of etching and true engraving, with etching becoming dominant in later examples, after the technique became popular in the 1830s. Engraving is done with a burin, which is a small bar of hardened steel with a sharp point. It is pushed along the plate to produce thin furrowed lines, leaving “burr” or strips of waste metal to the side. This is followed by the use of a scraper to remove any burs, since they would be an impediment during the subsequent inking process. Steel plates are very hard for this technique, which is normally used on softer copper plates.
So metal engraving also used etching, where acid creates the lines in the plates in the pattern made by selectively removing a thin coating of acid-resistant ground by tools. This is much less effort. As well as etching needles, the etched part of metal engravings made great use of roulettes, small wheels mounted in handles which have regular sharp projections which produce broken lines of dots and dashes when rolled across the plate. Roulettes of different types were used together with the burin and needle to create densely packed marks which appear as tonal to the eye, and allow a great variety of textures and effects. True burin engraving was generally used to finish the etched image.
First a broad, general outline is made on the plate before starting the detailed image. Metal engraving will produce a printed reverse or mirror image of the image on the plate. Sometimes engravers looked at the object, usually another image such as a drawing, that they were engraving through a mirror so that the image was naturally reversed and they would be less likely to engrave the image incorrectly.
19th century
Steel plates can be case hardened to ensure that they can print thousands of times with little wear. The copper plates used in traditional metal engraving and etching, which are softer and so much easier to work cannot be case hardened but can be steel-faced or nickel-plated by electroplating to increase the number of impressions that could be printed. From about 1860 the steel-facing of copper plates became widely used, and such prints tend also to be called steel engraving . It can be very difficult to distinguish between engravings on steel and steel-faced copper, other than by date.
The most reliable way of distinguishing between unfaced copper engraving and steel or steel-faced engraving is the “lightness and delicacy of the pale lines” in the latter. The hardness of the plate surface made it possible to print a good number of impressions without the metal of the plate wearing the lines out under the pressure of repeated intaglio printing, which would have happened with unfaced copper. So “A shimmering pale grey became for the first time a possibility in line engraving, and it is this that provides the most recognizable characteristic of steel beside the heavier and warmer mood of copper”.
Mechanical tools
From the beginning of the nineteenth century, new tools made engraving much easier and more exact. The ruling machine created parallel straight or wavy lines very close together, usually for use with etching. Another of these tools is the geometric lathe. The lathe is used to engrave images on plates, which are in turn engraved on rolls for such uses as printing banknotes. Another of these tools is the metal engraving machine. This machine uses a master template to lightly engrave a duplicate image which can be then engraved by hand or etched with acid. The machine also makes possible the reduction or enlargement of the letter for the duplicate image.
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