Always a colour conversion

Transferring images and artwork from a computer, scanner or digital camera always involves some kind of colour conversion. The digital colour scheme RGB combine light to make white, whereas the printable colour scheme CMYK combine ink to make black – and these different systems must be synchronized. Therefore, understanding how colours behave and should be managed during the prepress and printing processes, is crucial for the end result.

 

RGB

The RGB colour scheme is used in digital devices such as computers, scanners and cameras. The monitors in these devices use red, green and blue light to display colour. Each parameter (red, green and blue) defines the colour on a scale from 0 to 255. For example, an RGB value set to “0, 0, 255” is a bright blue and a value of “255, 255, 255” is white. Since four-colour printing presses use ink rather than light to define colours, certain bright and vibrant RGB colours you can see on your monitor will not appear as bright in print.

 

CMYK

The abbreviation CMYK stands for cyan, magenta, yellow and black. Commercial printing presses use ink of these four colours. Although the printing press is able to reproduce thousands of shades, the total is outnumbered by the RGB scheme. This means that there are unachievable RGB colours that are said to be “out of the CMYK colour gamut”. For this reason, you should always select colours from the CMYK colour scheme; a very useful tool is the Pantone Process Colour Guide. This swatch guide shows more than 3,000 CMYK mixtures for both coated and uncoated paper types.

 

Calibrations are crucial

To ensure the best printed result, with optimized colour match, you should always make sure that your monitors are calibrated and that your colour guides are up to date. Other aspects to keep in mind to ensure a smooth colour conversion is to use correct colour profiles and a reliable colour conversion program during the prepress phase.

Colour measuring equipments, light sources or illuminants, are also major sources of variations when calibrations are not correct.

 

Colour management in printing is a complex matter. Numerous factors have an influence on the end result and it is not easy to make the right choices. We are happy to help you understand what parameters are most important and how they should be managed – contact our technical specialists for more help.