Computer to Plate versus Computer to Film

Computer to Plate (CTP) is an imaging technology used in modern printing processes. In this technology, images are created in a Desktop Publishing (DTP) application and output directly to a printing plate. Unlike the previous technology where computer files are output to the form of film, and this film is then used to make printing plates. CTP has advantages over conventional platemaking. With CTP, the need for films and related developed chemicals is eliminated. CTP improves the sharpness and detail of the image on the plate. CTP avoids the potential loss in quality that may occur during the unselect of film, including scratches in the film, and variations in exposure. Plates are produced in less time, are more consistent and at a lower cost. CTP can also increase registers in the print process. The CTP system can significantly increase the plate production output. The platesetter for newspaper production can output up to 300 plates per hour at 1270 dpi (dots per inch), while for commercial applications the CTP system can produce 60 plates at 2400 dpi. 

Computer to plate (CTP) is an imaging technology used in modern printing machine processes. In this technology, an image created in a Desktop Publishing (DTP) application is output directly to a printing plate. This compares with the older technology, Computer to film (CTF), where the computer file is output onto a photographic film. This film is then used to make a printing plate, in a similar manner to a contact proof in darkroom photography. 

Advantages of CTP CTP has several advantages over conventional platemaking. In CTP, one generation (transfer of film image to the printing plate) is removed from the printing process, increasing sharpness and detail. Plates are produced in less time, are more consistent, and at a lower cost. CTP can also improve registration and image-to-edge repeatability over traditional methods. CTP, the media is registered (held in precise position) in the platesetter during imaging, and does not rely on a separately-aligned pin grid, as is the case with film. Defects due to dust, scratches or other artifacts are minimized. CTP systems can significantly increase print shop productivity. The fastest platesetters can output more than 120 12-inch plates per hour, punched and ready to hang on the press. CTP decreases dot gain slightly by eliminating the increase in halftone dot size which can occur in the film-to-plate exposure process when negative film is used (Mainly US) CTP increases dot gain slightly by eliminating the decrease in halftone dot size which can occur in the film-to-plate exposure process when positive film is used (Mainly Europe) Small portrait presses that typically create 1 or 2 color output can use anything from a standard laser printer, for low quality/low volume, up to a higher-end dedicated platesetter for higher quality and volume. 

Computer to Film Computer to Film (CTF) is a print workflow involving the printing from a computer, straight to film. This film is then burned onto a lithographic plate, using a plate burner. The plate is then put on an offset printing press to make a product (usually thousands of copies). This process requires a clean environment, skilled workers, and a well thought out proofing system / workflow to maximize quality. CTF is being replaced with the more advanced CTP (Computer to Plate) technology.