A determination system comprising: an imaging data acquisition device that is configured to capture an image of a printed surface of a printed product to acquire imaging data of the captured image; and a determination device that is configured to determine, based on the imaging data acquired by the imaging data acquisition device, a printing method used to produce the printed surface of the printed product for which the image is captured by the imaging data acquisition device, wherein the determination device is further configured to select a plurality of determination areas included in the captured image from the imaging data acquired by the imaging data acquisition device, acquire determination data based on a line-segment image included in each of the selected plurality of determination areas, compare the acquired determination data between two determination areas, and acquire, based on a result of the comparison, a determination value for determining a printing method used to produce the printed surface of the printed product, and determine, based on the acquired determination value, a printing method used to produce the printed surface of the printed product, wherein the determination device is further configured to determine that the printed surface is a printed surface printed with a printer that performs printing through scanning using a driving system in a case where the determination value indicates that an undulation degree indicating a degree of undulations of a line-segment image is greater than or equal to a preset determination threshold, or determine that the printed surface is a printed surface printed with a plate in a case where the determination value indicates that the undulation degree is less than the determination threshold. an imaging data acquisition device that is configured to capture an image of a printed surface of a printed product to acquire imaging data of the captured image; and a determination device that is configured to determine, based on the imaging data acquired by the imaging data acquisition device, a printing method used to produce the printed surface of the printed product for which the image is captured by the imaging data acquisition device, wherein the determination device is further configured to select a plurality of determination areas included in the captured image from the imaging data acquired by the imaging data acquisition device, acquire determination data based on a line-segment image included in each of the selected plurality of determination areas, compare the acquired determination data between two determination areas, and acquire, based on a result of the comparison, a determination value for determining a printing method used to produce the printed surface of the printed product, and determine, based on the acquired determination value, a printing method used to produce the printed surface of the printed product, wherein the determination device is further configured to determine that the printed surface is a printed surface printed with a printer that performs printing through scanning using a driving system in a case where the determination value indicates that an undulation degree indicating a degree of undulations of a line-segment image is greater than or equal to a preset determination threshold, or determine that the printed surface is a printed surface printed with a plate in a case where the determination value indicates that the undulation degree is less than the determination threshold.