Method for marking a plurality of sheets

A method for automatically processing a plurality of sheets, including printing and finishing with a printing system, the method comprising the steps of:

• receiving printing instructions for printing the plurality of sheets;
• receiving finishing instructions for finishing the plurality of sheets after printing in order to form a stack of printed and finished sheets, wherein the stack has a stack height and the finishing instructions comprises an instruction to create a new target stack edge extending in a direction of the stack height at an intended position on each of the plurality of sheets;
• printing a mark on each sheet of a group of sheets out of the plurality of sheets, the mark intended to hit the new target stack edge in a group of at least one target hit point;
• and
• finishing the plurality of printed sheets according to the finishing instructions to create a new actual stack edge,
• wherein a plurality of actual hit points of the plurality of marks, each of the plurality of actual hit points hitting the new actual stack edge and corresponding to one hit point out of the group of at least one target hit point, form a pattern on the new actual stack edge,
• wherein the pattern extends in a direction of the stack height and comprises an indication for a degree of correctness of the printing on the plurality of sheets and/or the finishing of the plurality of printed sheets out of a collection of continuous proportional indications for degrees of correctness,
• wherein the mark intersects the new target stack edge in the plane of the sheet with an angle that is smaller than ½ π radians,
• wherein the pattern comprises textual information or color information of the degree of correctness of printing and/or finishing, and
• wherein the textual information is a numerical indication of a deviation from the new target stack edge.