1. A method for preparing data for loading from a first data processing device into a second data processing device via a data connection, comprising the steps of: obtaining an x-ray image of an examination subject having an image field containing a subject image region representing the examination subject; in said image field of said x-ray image, automatically electronically determining a measurement field that is dependent on a position of the subject region in the image field; and automatically electronically determining grey scale values for visually representing said x-ray image exclusively from intensities in said measurement field.