In offset printing, books are often printed on large sheets of paper, with multiple pages on each side. These large sheets are called signatures, and after printing, they are folded and trimmed.
Using signatures in printing has several advantages. First, it allows for multiple pages to be printed in a single press impression, reducing the number of printing plates needed and minimizing paper waste. It also simplifies the printing and binding process.
What is Imposition?
Imposition is the process of arranging a book’s pages so that when the printed signature sheets are folded and trimmed, the pages appear in the correct order.
Special imposition software is typically used to arrange the pages into the optimal layout. The goal is to fill the master sheet as much as possible. Imposition is done during the pre-press phase, just before creating the printing plates.
In the illustration, you can see how the pages of an 8-page booklet might be imposed. The pages are arranged out of order, with some upside-down. However, this layout will produce pages with the proper orientation and sequence when the signature is printed, folded, and trimmed.
In this example, four pages will print on the front of the signature sheet and four on the back. After printing, the two-sided signature is folded in half horizontally, with page 3 touching page 2 and page 6 touching page 7. Then it is folded again vertically, so page 4 meets page 5. The booklet is bound along the spine fold, and the remaining folds are trimmed to allow the pages to open freely.
If you have any questions about printing, feel free to reach out to us at 718-928-6888 or submit our quote request form. We’re here to assist you in any way we can.
Take care!
Jeff @ New York Printing Center
