Abstract: Apparatus for an X-ray device, adapted for use with an X-ray tube, film and an object to be radiated disposed intermediate the tube and the film, comprises a restrictor plate of radiation-opaque material adapted to be disposed intermediate the tube and object and comprising a key-shaped gap configured and dimensioned to shape a beam of radiation passing therethrough from the tube to the object to obtain an advantageous darkness distribution on the film. The gap is preferably shaped like a downwardly converging key. The apparatus may additionally include a cover plate of radiation-opaque material adapted to be disposed intermediate the object and the film and comprising a gap configured and dimensioned to be slightly larger than the beam of radiation passing therethrough from the object to the film to minimize the diffraction of the beam intermediate the cover plate and the film.