Imposing

The act of locking-up pages in a chase, after it has been properly dressed with furniture. Much attention has been paid to this important branch of the compositor’s business in the various technical handbooks, and some ingenuity has been displayed in inventing new and improved modes. Imposing from the centre, by means of which the blank or open pages may be placed in the middle of the forme, leaving the solid pages on the outside to act as bearers for the rollers, as well as for the better regulation of the impression, is generally adopted for sheets of oddments, such as the title, dedication, preface, &c. Mr. Houghton, in his “Printer’ Practical Every-day Book” a several interesting examples of improvement on the old systems of imposition. The “American Printer” says:

“All odd matter for any forme should be divided into fours, eights, twelves, and sixteens, which is the ground-work of all the impositions except the eighteens, which differs from all others; for instance, sixteens, twenty-fours, and thirty-twos are only octavos and twelves doubled, or twice doubled, and imposed in half-sheets. The sixteens are two octavos impo[se]d on one side of the short cross; the twenty-fours are two twelves imposed on each side of the long cross; and a thirty-two is four octavos imposed in each quarter of the chase. Thus a sheet may be repeatedly doubled. By this division any forme or sheet maybe imposed, always bearing in mind that the first page of each class must stand to the left hand, with the toot of the page towards you. Having set down the first page, then trace the remainder according to the scheme which applies to its number, in proof of which the standard rule for all other impositions may be adopted,—namely, the folios of two pages, if placed properly beside each other, will make, when added together, one more than the number of pages in the sheet: that is, in a sheet of sixteen pages, one and sixteen coming together will add up seventeen, and so nine and eight will make seventeen; and so on. In halt-sheets, all the pages belonging to the white paper and reiteration are imposed in one chase. So that when a sheet of paper is printed on both sides with the same forme, that sheet is cut in two in the short cross if quarto or octavo, and in the short and long cross, if twelves, and folded as octavo or twelves.”

For the subsidiary operations of tying-up the pages, laying down pages, making-up furniture, making the margin, locking-up formes, &c., see those subjects in their alphabetical order.