Very thin ink layers are used in offset printing – a comparatively small amout of effect pigments can be applied to the material to be printed. Merck effect pigments with a particle size of up to 25 μm are therefore suited for this printing process – Biflair® 66 A and pigments in the Iriodin® Pearlprint Litho range in particular.
A printing blanket for the best results
When printing with Iriodin®, a printing blanket, which prevents the pigments from agglomerating too quickly, is recommended – especially when producing larger print runs.
Frequency-modulated screen resolutions intensify the effect
Conventional screens should not be finer than 34 lines per centimeter (85 lines/inch). Frequency-modulated screens are generally recommended, since their structure accommodates the appearance of the pigments and intensifies their effect. Screen dots finer than 30 μm are not advisable here, since they can cause problems when transferring the pigment platelets.
Optimum effect with wet-on-dry printing
While printing, the effect of Merck's effect pigments show their advantages best, if the pigment is applied wet to the dry process ink. Wet-in-wet printing creates a smoother picture – although the effect of the interference pigments may be diminished on a same colored background.
Pre-printing effect pigments wet-on-wet is not recommended due to the high thickness of the color layer, which is difficult to dry. Wet-on-dry printing should be used instead.