Applies to those components of X-ray equipment which - generate, influence the propagation of, and detect X-radiation; and - process, present and store radiographic information in radiological installations with diagnostic X-ray systems using radiographic films in direct radiography. This standard defines - the essential parameters which describe or affect the performance of the above components of X-ray equipment; - methods of checking that variations in measured quantities related to those parameters are within acceptable limits, in order to maintain adequate standards of imaging whilst reducing unnecessary irradiation of the patient.