The pen vibrates when writing on parts of the form with graphics on them, why?
This is probably because the colors of the form has not been properly separated. When using the Anoto pen nothing on the form, except the pattern, can be printed using carbon based black. When creating the output files the colors is automatically color separated if the correct printer profile has been used. In some cases the printer however replace some of the colors with a small amount of black and therefore confuses the pen.