Abstract: An apparatus in a multicolor rotary printing machine for determining register deviations, including a scanning device disposed behind a print gap of a last printing unit of the printing machine; at least one register mark line disposed on printing material movably disposed relative to the scanning device, wherein the scanning device is directed to the register mark line; a control circuit connected with the scanning device for processing signals from the scanning device, and a measuring, steering and regulating device receiving inputs from the control circuit in operative engagement with registers of the printing machine, and a plurality of section reference marks on the printing material, in alignment with the register mark line within scanning range of the scanning device for correcting the register deviations.