The term "siderographic" has been in use since the 1820s, according to this advertising note of Perkins, Fairman and Heath of London. A similarnote is in Stack's-Bowers 2015 New York International Numismatic Convention sale, lot 2102. Also see lot 2095 in that sale, a brochure on Perkins andFairman's "patent siderographic plan" published in 1819.

What does the term "siderographic" mean? I was unable to locate a dictionary definition.

The Greek word sidiros means iron (the metal), per R. Scott Carlton's International Encyclopædic Dictionary of Numismatics. The wordssiderographic, siderographer, siderography are probably derived from this Greek word. So the literal meaning must be something similar to "graphicarts of (or produced by means of) iron (or steel)." In his 2009 book The Feel of Steel, Mark Tomasko explains the term. Under the topic"transferring," Tomasko says:

Prior to leaving the United States for England, Jacob Perkins patented a stereotype steel plate for printing bank notes, and obtained alegislative monopoly in the Commonwealth of Massachusetts for the use of such plates in printing all bank notes of the $1, $2, $3 and $5denominations. Perkins wrote this up in a brochure titled "Perkins' Bank Bill Test; Consisting of Original Impressions from the PermanentStereotype Steel Plates ... " (etc.)

On June 15, 1813, Perkins also patented a transfer press for making multiple copies of hand-engraved images onto steel printing plates by means ofa roller die, per Greville and Dorothy Bathe's 1943 biography of Perkins, published by the Historical Society of Pennsylvania. Shown is a drawing ofthis transfer press and roller die taken from a plate in Bathe.

Perkins's argument for the superiority of the steel plates was that it would achieve "a perfect uniformity in Bank Bills," apparently theanticipated result of the improved durability of the steel plates when compared with the copper plates then in use. And with the bills' designs beingreplicable among different banks by means of siderography, bills of many banks could be made uniform.

Interestingly, the term "siderographer" did not catch on with the artisans themselves. Their trade union was named the International Steel PlateTransferrers Association of America. Early in the 20th century they joined what is now the International Plate Printers, Die Stampers, Plate Makersand Engravers Union of North America, whose attractive souvenir convention booklets of engravings have become quite collectible.