CTP

(1) (Computer-To-Plate) The production of printing plates directly from the computer without requiring film as an intermediate step. Also called "direct-to-plate," the plates are typically made of aluminum, but polyester, polymer and silicon plates are also used. Off-press imaging refers to using a platesetter to create the plates and then manually attaching the plates on the press. On-press imaging, or direct imaging (DI), images plates that are already on the press. In 1988, Presstek, Inc., Hudson, NH www.presstek.com) was the first to introduce an on-press system, using spark discharge technology to image the plates. Lasers were used in subsequent models. See digital workflow and DI press.

Newspaper Plate Making

The Newsmatic series of CTP machines from ECRM Imaging is used in the newspaper industry for large format plates. With a capacity from 25 to 250 plates, depending on model, it can produce 80 pages per hour at 2540 dpi. (Image courtesy of ECRM Imaging Systems, Inc., www.ecrm.com)

(2) (Computer-To-Press) Printing directly from digital files. The term is more ambiguous than definition #1. Since all computer printers are computer-to-press, it could refer to a large digital printer. It could also refer to an on-press computer-to-plate machine. It would not refer to off-press computer-to-plate (see above).

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