A printing system includes the following elements. An addition unit creates additional image data having a specific attribute and adds it to original image data, thereby creating document image data. An image forming unit forms a document image including an original image and an additional image on a recording medium on the basis of the document image data. An image reader reads the document image, thereby creating read image data. A difference image creator creates difference image data by calculating a difference between the original image data and the read image data. A canceling unit corrects, on the basis of the specific attribute, the difference image data by canceling a difference generated due to the addition of the additional image data, thereby creating corrected difference image data. An inspection unit performs inspection to find a defect of the original image on the basis of the corrected difference image data.