Black separation strategies in colour reproduction

The goal of the research presented in this paper was to investigate different strategies for black colour separation in four-colour CMYK reproduction process. This work describes some extended behaviour in making of separations by applying achromatic substitution strategies. The results have shown that appropriate substitution can lead to higher black ink amount then theoretical, when using some output device profiles. Additional consequences of that can be recognized in IR spectral domain, where the black ink renders significantly lower reflection then by using process inks. This effect enables the possibility of producing some special purpose graphics and security graphics.