A method is disclosed for producing projective and tomographic phase contrast images of an examination object, preferably a patient, with the aid of an X-ray system, and a corresponding X-ray system for carrying out this method. In at least one embodiment of the method, X-ray optical grating sets tuned to different energy ranges are used to determine energy-dependent phase shifts upon penetration of an examination object, a difference value is formed from these energy-dependent phase shifts, and tomographic or projective images are produced therefrom.