The term “colour scale” has two meanings in the printing industry:
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 early installations of Photoshop from the 90s numerous Euroscala or Euro Scale profiles have been installed, which still haunt some software. In particular, the UK’s profile still seem to have some spread.
The use is, however, no longer recommended. Please change to the current ISO standards, which can be downloaded on the website of ECI for free.