A printing machine has different printing stations for each colour or varnish to be included in the design. Cartonboard sheets are loaded onto the printing machine and printed in one pass with each colour being added in each of the printing stations. A variety of printing processes may be used including offset / lithographic, flexographic, gravure and in some cases, digital printing. Digital Printing is still an emerging technology that is expected to become more important for carton production in the future. It allows customized prints of very small order sizes.
Several cartons can be printed on one sheet of cartonboard, so a layout is created to ensure that as little cartonboard waste as possible is created from each sheet. This layout is also used to prepare the creasing and cutting forms that will be used later in the production process.
Most cartons are printed using six colours, depending on the specification that comes from the brand owner. As well as the colours that are applied to the cartonboard, a varnish that improves the gloss finish or that adds a highlight is often printed on the board on top of the printed colour. Cartonboard can also be laminated with aluminium foil, metallised polyester, greaseproof paper, glassine or coated paper.