Comparative analysis of electrophotographic prints with the standard magenta and cyan in relation to the prints in which light magenta and light cyan are added

The satellite machine construction enables the positioning of greater number printing units which can print greater number of colours. They are most often Pantone inks and in recent times the clear varnish as well. EP machines which use the liquid EP inks (Digital Colour Offset) can contain up to 7 printing units. In this work the spectrophotometric analysis of magenta and cyan prints has been done (4 colour print) in relation to the 6 colour print (the added light cyan and light magenta). With it the continuous wedge is reproduced, containing 9 specific screen patches. The addition of lighter inks in screen reproduction does not achieve considerable visual changes in tone (DEmax=3, 00). But they are more expressed in magenta DEmean=2, 16 in relation to cyan DEmean=1.18. On prints, the light screen elements are applied up to 40% of screen value, after which they change into the full tone. Medium and dark areas contain 100% of the applied light ink to which the screen elements of the darker inks are added. With it the diameters of the screen elements range from 56, 5 μm up to 96, 02 μm, while diameters of the dark screen elements range from 37, 64 μm up to 135, 91 μm.