Special colours are printing colours which are used in addition to or instead of the basic colours of the CMYK system. They come ready mixed in the printing press. The use of special colours makes the printing process simpler. For each special colour you need an additional colour separation and an additional printing form. Moreover, additional costs can arise in reproduction or production run printing. Nonetheless, special colours are centrally important in packaging printing.
- Some printing results, e.g. certain light colours, metallic effects or colourful processes cannot be produced via a CMYK mix.
- If the individual colour separations are not printed over each other exactly in multicoloured printing, slight mis-registrations and colour deviations arise. The targeted use of special colours can help with this ‘matching’ problem.