January 4

Henry George Bohn, English linguist, bookseller, publisher, and art connoisseur , was born upon this day in 1796. He achieved distinction in all of these endeavors until his death in his eight-ninth year. Appearing before the Philobiblon Society in April, 1857, he gave a long and curious lecture concerning the history of printing. It was published in an edition of only thirty-seven copies.

Most of the speech, entitled The Origin and Progress of Printing, was a warming over of a variety of old saws about the craft. But when Bohn arrives at the “Progress” section of his talk, he becomes fascinating to modern students of the craft. Many of the processes which he discusses with some enthusiasm are now long since forgotten but remain on interest nevertheless, particularly when described in Bohn’s quaint terminology.

The anastatic process was delineated as a method by which “exact facsimiles are produced from printed pages while they are recent, or at least before the oil is entirely exhausted by age.” Bohn when on to describe it as “one of the branches of chemical printing, and like its congenitors, lithography and zincography, depends on affinities and antipathies. The printed page or engraving is prepared in such a way as to soften the ink and acidulate the paper. It is then laid on a polished zinc plate and submitted to great pressure, by which the black lines become transferred, and the intervening white parts etched away by acid, while the original print is not perceptibly deteriorated, unless the operation is clumsily performed.”

Photography is mentioned as a printing process, with a subtitle of sun-printing, “a new and valuable art by which external objects are delineated on chemically prepared plates or paper, by means of the camera obscura.” Informing his audience that the subject was too well known for a detailed discussion, Bohn went on to mention a new phase of it called the dry collodion process, by which “The prepared plates are sold ready for use, occupy very little space in travelling, and will keep sensitive for an almost indefinite period. After the required number of views have been taken, the plates may remain in the portmanteau for months, till there is a convenient opportunity for developing them at home.”

After dwelling upon chemitipy, nature printing, siderography, and compound printing, Bohn becomes the contemporary of present-day lecturers by describing the mathematical, or table printing of which “Mr. Babbage is the originator. By its self-acting changes, arranged to a great nicety, it calculates, according to any given formula, with more certainty than human power.”

Some of our modern computer engineers should read Mr. Bohn, as the 19th century device he described was also capable of producing stereotypes!

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