Rch black

Using multiple ink colours in addition to black to produce a deep, dark black colour.

Register marks

Any crossmarks or other symbols used on a press sheet to assure proper registration.


The arrangement of two or more printed images in exact alignment with each other.


Abbreviation for red, green, blue, the primary colours of light, which computers use to display images on screen. An RGB file must be translated into CMYK in order to be printed on a printing press.