A printing system and printing apparatus are provided with improvements in the image quality of an image formed on a printing medium, a peel off region (PO) wherein a transfer layer of a transfer film is not transferred is set corresponding to a card, modified printing data is generated by modifying a gray-scale value of printing data inside a region that is larger than the PO region by predetermined dimensions and including the PO region in the printing data of Y, M, C and Bk into a gray-scale value of 0, an image is formed on the transfer film by heating a thermal head for an image formation panel of an ink ribbon according to the modified printing data. The transfer layer is peeled off by heating the thermal head for a peel off panel of the ink ribbon according to position information of the PO region.