The steady advancement of technology affects every industry – and printing is no exception. Since the printing press was invented in the 1400s, there have been constant efforts to improve productivity and efficiency.
Computer page layout software became available in the late 1980s, making it possible to produce colour-separated films that could be used to make to printing plates.
One of the more recent advancements in the printing industry is computer-to-plate technology, which omits films altogether.
Computer-to-plate is a streamlined process of printing plate production. It takes a computer-generated file (usually a PDF) and outputs it directly to a plate that can be used on the press. The plates are made from a variety of materials, such as aluminium and polyester.
Before computer-to-plate, computer-to-film was used. With computer-to-film, the image is outputted to a photographic film (positive or negative image), and the film is then used to make the printing plates. The computer-to-film process is similar to darkroom photography, which computer-to-plate technology helps to eliminate.
Computer-to-plate is easy to use and efficient. It skips the film step, saving time and money. Without films, the associated chemicals and bio-hazards are completely eliminated. And because computer-to-plate is a much faster process than film-based plate-making, productivity is also greatly increased.
Computer-to-plate technology uses an internal drum, external drum or flat-bed image setter and ultraviolet light lamps or laser diodes to expose the image onto the plate.
Computer-to-plate has multiple advantages. The biggest advantage is removing the film generation and chemical usage layer. Computer-to-plate improves the quality of output as the intermediate films used in other methods can potentially have scratches, dust or other issues. But overall, computer-to-plate is preferred for its faster process and cost-effective nature.
The main disadvantage of computer-to-plate is that the print file must always be in a digital format, and if any correction is needed, a completely new plate needs to be created. This could, however, be seen as an advantage as the correct version is then archived and if a reprint is required, any changes that have been made will be carried through to the next print.
Computer-to-plate technology offers the following benefits:
- It increases the sharpness of the type and image detail as one generation of image reproduction is removed.
- It eliminates plate defects caused by scratches in the emulsion and dust on the film, as well as defects from variations in film exposure and processing.
- It eliminates the cost and management of film and related processing chemicals, saving money and benefiting the environment.
- It offers a huge productivity gain over film-based workflows, with quicker, more accurate and consistent imaging of printing plates and plates can even be burned unattended.
In a nutshell: computer-to-plate technology increases plate-making speed and quality and is by far the most widely used and preferred plate-making technology today.