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What Does Computer-To-Plate Mean?

Computer-to-plate (CTP) is an imaging technology which helps to transfer a digital image generated in a computer directly to a printing plate. Before
CTP, the technology used was computer-to-film (CTF), where the image output
was passed to a photographic film, and the output film was then used to make
the printing plate. This process is similar to darkroom photography. The CTP
technology helps to eliminate all the darkroom processes, and hence is cost
effective. CTP is a much faster process compared to film-based printing, so
the productivity of printing increases greatly.


Techopedia Explains Computer-To-Plate

CTP technology is based on the
construction of the image setter and the source of light exposed to the plate. There are three different construction types:

  • Internal drum
  • External drum
  • Flat-bed image setter

And there are two types of light sources: ultraviolet light lamps and laser
diodes. In case of laser diodes, the energy and wavelength depends upon the type of plates used in the system. It is widely used in the newspaper and magazine
printing industry.

CTP has multiple advantages over the other conventional printing processes. The biggest advantage is removing the film generation and chemical usage layer. CTP improves the quality of output as the intermediate films used in other methods can potentially have scratches or other issues. However, there are some disadvantages in the CTP process, the biggest being that the image must always be in the digital format, and if any correction is needed, a completely new plate needs to be created. But overall, CTP is preferred for its faster process and cost-effective nature.


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Margaret Rouse
Senior Editor
Margaret Rouse
Senior Editor

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.