1. A method for rendering an image comprising the steps of: Emitting x-rays from an x-ray source, using predetermined imaging parameters, to obtain a direct radiation image without any imageable object in a path of said x-rays, and generating a calibration image from said direction radiation range, said calibration image having an intensity distribution; generating an x-ray image of an examination subject using said predetermined image acquisition parameters, said x-ray image having an intensity distribution and having an image field containing a subject image region representing the examination subject; automatically determining said intensity distribution of said x-ray image of said examination subject; in a computerized processor, automatically determining a measurement field in said image field of said x-ray image, by comparing the intensity distribution of said calibration image with the intensity distribution of said x-ray image of the examination subject; and in said processor, automatically determining grey scale values for visually representing said x-ray image exclusively from intensities in said measurement field.