Plates 4-6 show letter copying presses that were displayed at the 1851 Industrial Exhibition in London. Along with typewriters, letter copying presses are the most common machines found in photographs of late 19th century and very early 20th century offices. Yates (Ch. 4-5) reports that the Illinois Central Railroad used copying presses to make copies of outgoing letters in press books at least from the late 1850s to 1896, that the Repauno Chemical Co. stopped using press books in 1901 (p. 226), that the Scoville Manufacturing Co. was still using copy presses and press books for outgoing letters in 1913 (p. 181), and that the Hagley Museum and Library has press books that were used in the 1930s (p. 283). The last U.S. President whose official correspondence was copied on a copying press was Calvin Coolidge (1923-29). (David Owen, "Making Copies," Smithsonian, Aug. 2004, p. 92) Screw model letter copying presses were still marketed in 1950, and Proudfoot reports that an organization in London, England, was still using press books in the late 1950s. (W. B. Proudfoot, The Origin of Stencil Duplicating, 1972, p. 32) Because of the size and weight of letter copying presses, numerous portable methods for pressing loose copies and copy books were also marketed during the 19th century.
In a review of office equipment at the 1851 Industrial Exhibition, Granville Sharp recommended that when an office was selecting a press like those in Plates 1-3, it should make sure that the handle was heavily weighted at the ends to insure proper spinning. “This is essential to a screw copy press; for unless one pull will serve to raise or to depress the plate, much time is lost.” In addition to the press, offices needed to buy copying books that contained up to a thousand pages of tough tissue paper, copying ink, copying paper dampers, oiled paper, and blotting paper.
Sharp explained that before using the new press, the office had to decide how to organize its letters. Production of copies was easiest if the user copied its letters into a single letter book in chronological order. In that case, the user needed to make an index so that letters of interest could later be retrieved. Alternatively, the office could organize its correspondence by client, which avoided indexing but made it necessary to use numerous copying books on a given day.
Although copies could be made up to twenty-four hours after a letter was written, copies made within a few hours were best. A copying clerk would begin by counting the number of letters to be written during the next few hours and by preparing the copying book. Suppose the clerk wanted to copy 20 one-page letters. In that case, he (copying clerks were men) would insert a sheet of oiled paper into the copying book in front of the first tissue on which he wanted to make a copy of a letter. He would then turn 20 sheets of tissue paper and insert a second oiled paper. Sharp advised that “Success in copying letters depends almost entirely upon the damping of the paper. The paper should be saturated and damp, not wet.” To dampen the tissue paper, the clerk used a brush or copying paper damper. The damper had a reservoir for water that wet a cloth, and the clerk wiped the cloth over the tissues on which copies were to be made. (See Plate 5A) As an alternative method of dampening the tissue paper, in 1860 Cutter, Tower & Co., Boston, advertised Lynch's patent paper moistener (Plate 5B) with the claim that "it does away with the use of the brush, wet cloths and dipping bowls, and dampens the paper sufficiently by a single roll of the machine."
Next, letters were written with special copying ink, which was not blotted. The copying clerk arranged the portion of the letter book to be used in the following sequence starting from the front: a sheet of oiled paper, then a sheet of letter book tissue, then a letter placed face up against the back of the tissue on which the copy was to be made, then another oiled paper, et cetera, “oiled paper being in all cases placed next the damp paper, to prevent the ink forcing beyond the paper intended to receive it.”
Finally, “Close the book, put it into the press, and screw tightly down, letting it remain a minute or two under pressure, when the copy will be properly taken, and may be dried with blotting paper, or held near the fire.” Based on experience, the clerk could adjust the press time. If he made a copy soon after a letter was written, only a second or two was needed to make a good impression. When the letter book was pressed, some of the ink transferred from the letters to the moist tissues in the book. Because the ink penetrated the tissues, copies could be read from the front sides of the tissues.
Prior to the introduction of inks made with aniline dyes, the quality of copies made on letter copying presses was limited by the properties of the available copying inks. The first aniline dye was invented in 1856, and numerous aniline dyes were invented in the following two decades. Bedini (p. 193) reports that "The growth of the aniline dye and ink manufacturing industries in Germany, which coincided with the earliest importation in 1868 of thin papers manufactured in Japan, brought a new popularity to the bound letter book."
Some documents that were to be copied with copying presses were written with copying pencils rather than copying ink. The cores of copying pencils, which appear to have been introduced in the 1870s, were made from a mixture of graphite, clay, and aniline dye.
