<p>The present invention relates to calibration in X-ray phase contrast imaging. In order to remove the disturbance due to individual gain factors, a calibration filter (10) for an X-ray phase contrast imaging arrangement is provided that comprises at least one slab of filter material (12). The filter material is made from a material with structural elements (14) comprising structural parameters in the micrometer region. The filter is configured to be temporarily arranged between an X-ray source grating and an interferometer unit in a phase contrast imaging arrangement.</p>
