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Old presses in the Musée Plantin-Moretus, Antwerp. The business of this printing-office was carried on without interruption from 1579 to 1800, first by Plantin, and afterward by the family of his son-in-law Moretus. It is now owned by the corporation of Antwerp, and it presents a unique picture of a printing-office of the sixteenth century, every thing connected with the operations of printing being left in a state of readiness, as if work were to be resumed the next day.
accomplished by the use of the double cylinder machine which, through a most ingenious contrivance of the two cylinders, admits of two sheets being printed at the same time.
Making Ready.-This operation, to which reference has already been made, is probably the most important part of press work, as upon its proper execution largely depends the appearance of the printed sheet. The pressman who is able to "make ready" and prepare the "overlays" for fine illustrated work commands a high salary in any printingoffice where such work is executed.
All forms require more or less "making ready," for even with the utmost care in casting and finishing plates, it is quite impossible to obtain a number of plates whose face and thickness shall be absolutely true. There will be depressions in the plates in some spots where the plate, in printing, seems scarcely to touch the paper, and corresponding elevations in other places. The first impression taken from a form is, therefore, more or less imperfect, and it is the work of the pressman to overcome these irregularities, either by "overlaying" or " underlaying" as may depend upon the character of the press. This process is a very nice one, and it requires no slight amount of judgment upon the part of a pressman to do it effectively. Small pieces of very thin paper are cut and pasted over the low spots either upon the cylinder, or (in the Adams press) underneath the plates. When the impression is too heavy the soft covering of the cylinder is cut away in the proper spot and the pressure equalized throughout the entire form, thus giving an even appearance to all the printed pages.
When, however, wood-cuts appear in the text, the difficulties of "overlaying" are greatly increased, and the expert pressman must possess a good deal of artistic judgment to prepare his form so as to produce effectively in the printed