Commercial processes

The main commercial printing process for paper and boards is offset lithography. This is a common process used in printing as it is suitable for large print runs and gives a high-quality print to a consistent standard. Offset lithography prints small dots in four main colours that overlay each other to create the full colour spectrum. Ink is transferred (offset) from a metal plate to a rubber roller, and the paper or card never comes into contact with the image on the plate.

The four colours are printed to check the alignment of the printer by producing what is known as a registration mark. The four colours are cyan, magenta, yellow and black (CMYK). CMYK is a colour model, where cyan (C) is blue, magenta (M) is red, (Y) is yellow and (K) is key. The term ‘key’ is used rather than black because the three printing plates, C, M and Y are all ‘keyed’ and aligned with the black plate.

A grey printing press with four modules for each colour of CMYK (magenta, cyan, yellow and black).
Printing press with four modules - each module has a press that prints a different colour from CMYK

Once printing has taken place, the paper or card needs to be cut to size and sometimes folded. Die cutting is a commercial process that accurately cuts and creases paper or card at speed. Within a die cutter, sharp blades are arranged to produce a cut, while rounded blades are arranged to produce a crease - this allows for the material to be folded rather than cut.

A typical school die cutter trimming a single rabbit shape from a small piece of card aside a commercial die cutter trimming several identical shapes from a long strip of card.

The arrangement of sharp and rounded blades produces a net as the card is stamped by the die cutter. Some die cutters can be found in schools, and these smaller versions produce one net at a time. Commercial die cutters are often on a roller and cut the card as the roller passes over the material.

A man’s hands are shown using a machine for die cutting.
Die cutting