An ink jet print apparatus having a plurality of double-sided printing modes (e.g., automatic double-sided printing mode and manual double-sided printing mode) produces a sufficient image quality whichever mode is executed. For this purpose, image data to be printed is converted into print image data usable by the printing apparatus in a way that matches a selected one of multiple print medium transport paths. This minimizes a curling problem due to variations in transport processes, image quality variations caused by an ink fixing problem and adverse effects on the printing apparatus and ensures a stable printing whichever transport path is used for printing.
