In the past, people use CTF technology in offset printing. The print design is output to the photographic film first, then the printing plate(mainly PS plate) is made. However, in the contemporary printing process, artwork in PDF format—typically produced by desktop publishing programs like Adobe Photoshop, Adobe Illustrator, Adobe Indign, and others—is output directly to the printing plate. And this technology is known as CTP(computer-to-plate). Compared with CTF, CTP has many advantages.
What Is CTP?
CTP, or computer-to-plate, has digitized plate-making processes using modern imaging technology. It uses laser beams to image directly onto a printing plate rather than exposing a film and then transferring it to the plate, as in darkroom photography.
How Does CTP Work?
CTP is a streamlined process of print production. Streamlined in that takes a finalized file from a computer and outputs it directly to a plate. The plates are made from a variety of materials ranging from aluminum to polyester. Once the plate is imaged, it can be used on the press. The plates are comprised of a range of materials, including aluminum and polyester. The plate can then be utilized on the press after it has been imaged.
What are the Differences Between CTP and CTF?
In the printing press, the CTF is film printing; while CTP is a plate-making method in which the numbers or pages edited in the electronic prepress processing system or the color desktop system are directly transferred to the printing plate.
CTP is easy to use and efficient. It saves money and time because it skips an entire step (the steps of film exposure rinsing, revision, and printing) when compared to the old CTF process.
Comparison Diagram
Advantages of CTP
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Sharper images and more details; One generation (image transfer from the film to the printing plate) is removed from the printing process (the need for film and associated developer chemicals is eliminated).
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less potential losses in quality; CTP prevents possible losses that could happen during film processing, such as scratches in the film and variations in the exposure. An imagesetter usually has an accuracy rate of ±2%.
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more affordable; Plates are manufactured in less time, with greater consistency, and at a lower cost.
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more precise; CTP can also increase image-to-edge repeatability and registration over traditional approaches. Recent developments in CTP plate technology by firms such as Dupont and PlateCrafters have stretched the gap with analog plates even further, allowing for very fine vignettes and minimum dot gain on press.
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more productive. CTP systems have the potential to greatly boost plate production output. Platesetters for newspaper manufacturing may produce up to 300 12-inch (300 mm) plates per hour at 1,270 dpi (dots per inch), but a CTP system can produce 60 B1 plates at 2,400 dpi for higher screen rulings.
Disadvantages of CTP
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Restricted to digital format. CTP productions necessitate a digital basis for both printed matter and imposition.
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Remaking of plates. If for some reason the CTP plate is damaged, if there is an error in ripping, or if there is something that needs to be corrected after the plate is exposed, a brand new, imposed plate must be created.