A method for determining printed images with respect to printing groups, comprising the use of a printer with at least one first and one second printing groups including respective first (R 1) and second (R 2) printing rollers having one and the same printing development, each of said printing rollers (R 1, R 2) with at least one respective characteristic image (M 1; M 2) to be printed on a laminar material, said characteristic images (M 1; M 2) being auxiliary marks and said method comprising: i) actuating at least said printing groups to perform a first printing of said characteristic images (M 1, M 2) on said laminar material to be printed; and said method being characterized in that it comprises determining which roller is associated to each of said characteristic images (M 1, M 2) by means of the automatic and sequential performance, after said step i), of the following steps: ii) detecting, by means of an automatic detection system, said characteristic images (M 1, M 2) once they have been printed on the material to be printed, to at least identify them and know their relative position within said printing development, iii) moving in a controlled manner the transverse and/or longitudinal register of at least one of said printing rollers (R 2), iv) actuating at least said printing groups to perform a second printing of said characteristic images (M 1, M 2) on said laminar material to be printed; v) detecting on the material to be printed, by means of said automatic detection system, said characteristic images (M 1, M 2) printed on the material to be printed, to at least identify them and know their relative position within said printing development, vi) comparing the result of the detections of step v) with that of the detections of step ii) to determine a possible positional discrepancy for at least one of the characteristic images (M 1, M 2), vii.1) determining that one of said printing rollers (R 1, R 2) is associated to a characteristic image (M 1, M 2) which has undergone a positional discrepancy, which is at least one in number, at least if the transverse and/or longitudinal register of said printing roller (R 1, R 2) has been moved in said step iii), and/or vii.2) determining that one of said printing rollers (R 1, R 2) is associated to one of said characteristic images (M 1, M 2), which has not undergone a positional discrepancy, if the register of said printing roller (R 1, R 2) has not been moved in said step iii). i) actuating at least said printing groups to perform a first printing of said characteristic images (M 1, M 2) on said laminar material to be printed; ii) detecting, by means of an automatic detection system, said characteristic images (M 1, M 2) once they have been printed on the material to be printed, to at least identify them and know their relative position within said printing development, iii) moving in a controlled manner the transverse and/or longitudinal register of at least one of said printing rollers (R 2), iv) actuating at least said printing groups to perform a second printing of said characteristic images (M 1, M 2) on said laminar material to be printed; v) detecting on the material to be printed, by means of said automatic detection system, said characteristic images (M 1, M 2) printed on the material to be printed, to at least identify them and know their relative position within said printing development, vi) comparing the result of the detections of step v) with that of the detections of step ii) to determine a possible positional discrepancy for at least one of the characteristic images (M 1, M 2), vii.1) determining that one of said printing rollers (R 1, R 2) is associated to a characteristic image (M 1, M 2) which has undergone a positional discrepancy, which is at least one in number, at least if the transverse and/or longitudinal register of said printing roller (R 1, R 2) has been moved in said step iii), and/or vii.2) determining that one of said printing rollers (R 1, R 2) is associated to one of said characteristic images (M 1, M 2), which has not undergone a positional discrepancy, if the register of said printing roller (R 1, R 2) has not been moved in said step iii).