The term “colour scale” has two meanings in the printing industry:
1. standardised printing colours (process colours) for four-colour printing (CMYK), e.g. the Euroscale.
2. proof scale: A schematic ink sample that is produced during a press proof and serves as a basis for the customer’s assessment of the printing failure and as a binding template for correct colour guidance in the production run.
In four-colour printing, for example, such a scale consists of one single print each in cyan (C), magenta (M), yellow (Y) and black (K), as well as three different combined prints in which first two, then three and then all four colours are printed together.
In contrast to the proof, a press proof is created using films or CTP printing plates on special press proofing machines with the same colours and parameters as the subsequent production run.
A press proof is very precise in terms of colour and, due to the edition paper used, is almost identical to the later print. Compared to the classic proof, however, a press proof is usually tens of times more expensive and quickly costs several hundred euros. Moreover, a press proof needs much more time for the production. Therefore, it is hardly relevant today for economic reasons and is only used for very delicate prints with high print runs.