![]() ![]() For the imposition of an A4-sized hardcover book on A3 paper, for example, one could first write a shell script to re-arrange the document in the following sequence: 1, 32, 31, 2, 3, 30, 29, 4.A trivial script might be written to re-arrange pages in a PostScript or PDF file to make them suitable for final imposition through the built-in Page Setup. This approach works particularly well on desktop Unix in a small office/home office environment (where a printer may only be capable of handling A3 and smaller). Imposition through shell scripts and operating system features.This larger layout is then printed to film or a plate. This typically takes a document prepared as single pages and creates a new document with full-sheet layouts. This is still in use, especially for low volumes of work, but a popular alternative is an imposition function built in, or added in, to the design tool. Software packages that can be used to design single pages can often be used to design entire printed sheets, sometimes by a process as simple as copy/paste onto a larger sheet. There are several different approaches to digital imposition. In turn, digital techniques help to reduce material costs, time and resolves production bottlenecks. Binding options may be changed on the fly and impositions produced to multiple output devices at once, often with no user intervention. An entire book may be imposed and many complex functions applied in an instant. The advent of digital imposition has not only helped a lot in making sure layout and sheet arrangement are correct with higher register precision, but it significantly reduces the usual imposition errors (e.g., slight movements of register due to parallax). The first digital imposition software, Impostrip, was released in 1989. Manual imposition processes tend to cause bottlenecks of the whole printing production. In addition, an extremely high precision would be needed for stripping of colour work, as each ink colour is on a separate piece of film. Digital techniques rendered stripping less necessary, but what has forced increasing numbers to abandon it completely is the introduction of "platesetters", which put pages directly onto printing plates these plates cannot be adjusted with a sharp knife. The term stripping was also used for other changes to a prepared page, such as a spelling correction, or a stop press story in a newspaper. Skilled workers would spend many hours stripping pieces of film together in the correct sequence and orientation. These sheets were combined manually on a light table, in a process called stripping. When pages were set using movable type, pages were assembled in a metal frame called a chase, and locked into place using wedges called quoins.īy the late twentieth century, most typesetting was onto photographic film. Imposition has been a requirement since the earliest days of printing. A little copy is then created, and this can help paginate the product. This is made by folding several sheets of paper in the way the press will print and fold the product. To understand how the pages are related to each other, an imposition dummy may be used. These fibers must run lengthwise along the fold, which influences the alignment, hence the position, of the pages on the printed sheet. ![]() Paper fiber direction: Many papers have a "grain," reflecting the alignment of the paper fibers.Stitching/binding method: The compositor must understand how the sheets are placed to form the signatures that compose the finished book.Number of pages of the printed product: The compositor must determine how many sheets are to be printed to create a finished book.Format of the product: The size of the finished page determines how many pages can be printed on a single sheet.The arrangement of pages on the printer’s sheet is affected by five different parameters: To achieve this, the printed sheet must be filled as fully as possible. It consists of the arrangement of the printed product’s pages on the printer’s sheet, in order to obtain faster printing, simplify binding and reduce paper waste.Ĭorrect imposition minimizes printing time by maximizing the number of pages per impression, reducing cost of press time and materials. Imposition is one of the fundamental steps in the prepress printing process. ( June 2014) ( Learn how and when to remove this template message) Please see discussion on the linked talk page. This article appears to contradict the article Letterpress#Imposition. ![]()
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