Steel engraving

It is pushed along the plate to produce thin furrowed lines, leaving "burr" or strips of waste metal to the side.

So steel 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.

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.

The copper plates used in traditional 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.

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".

Copper, being a soft metal, was easy to carve or engrave and the plates could be used to strike a few hundred copies before the image began to severely deteriorate from wear.

For this reason, copper plates were the preferred medium of printing for mapmakers, who needed to alter their maps whenever land was newly discovered, claimed, or changed hands.

During the 1820s steel began to replace copper as the preferred medium of commercial publishers for illustration, but still rivaled by wood engraving and later lithography.

Also, the harder steel plates produced much longer wearing dies that could strike thousands of copies before they would need any repair or refurbishing engraving.