Most printed items print in Cyan, Magenta, Yellow and Black – the subtractive colours, all other colours being a mix of these four. They are referred to as the Process colours. Somewhat confusingly, these are abbreviated to CMYK – K is used to represent ‘Key’ providing detail and contrast on an image.
The range of colours that can be achieved by mixing CMYK is called the gamut. The gamut of standard CMYK printing inks is quite limited, however, colours outside of this gamut are available in the form of Pantone inks. Pantone inks offer a consistent reproduction of a colour and are therefore often used in company logos.
The CMYK inks or toners used in digital printing presses often have a wider gamut than litho inks and are therefore capable of matching a wider range of Pantone colours.
RGB (the additive colours) are used for digital reproduction on screens and self-lit systems. Typically, scanned images and digital photographs are generated in the RGB colourspace. RGB has a significantly wider gamut than CMYK, however, it is necessary to convert RGB to CMYK before files can be printed.There are an infinite number of ways of making this conversion – all of which will produce slightly different results as the wider RGB gamut is constrained into the smaller CMYK one. It is therefore recommended, for control and consistency, to ensure all placed images are CMYK.
The digital press in Print Services has some special colour capability including white, gold, silver and clear. These can be used creatively to produce a range of effects – speak to our design team if you would like to know more.
