Traditionally, plates are created through a time consuming prepress process that involves creating CMYK color separations and then developing large film negatives from which the plates are made. Once the plate is created, it is wrapped around the plate cylinder and water is applied to the non-image areas and ink is applied to the image areas. The plate cylinder then comes into contact with the blanket cylinder and the image is transferred to it. The blanket cylinder is has a rubber blanket wrapped around it that picks up the image from the plate cylinder. The substrate passes between the blanket cylinder and the impression cylinder where the image is passed to the substrate.
Commercial presses are very fast and have very high quality output.
Digital printing is typically used for shorter run paper based jobs such as reports, newsletters, books, brochures, etc. Digital printing has some distinct advantages over the other printing processes. The other processes are incapable of producing variable data which is the ability to create sections of a job that vary from page to page. An example of this would be a phone bill in which your name, account number, address, etc are printed on the bill. Many digital printers can pull this information from a database and incoporate it into a job.