1. A method for a determining the reliability of and the reading quality of a radiographic medium produced in carrying out a diagnostic mammographic procedure, said method including the steps of positioning a test-material-carrying tab to overlie breast tissue in a path of a radiation source to be directed onto the tissue to be examined for producing a radiation-derived image on a mammographic medium, wherein said test-material is composed of particles whose X-ray image is used for determining the quality of the radiographic medium, activating an X-ray emanating source to generate a beam of radiant energy, directing the beam of radiant energy to impinge on the tissue-carried tab, on the test material of the tab, on the tissue to be examined, and on radiation-sensitive radiographic recording medium, simultaneously exposing the test material, the tissue and the recording medium to the radiant energy for generating a latent image of the irradiated tissue and of the irradiated test material of the tab, and processing the exposed radiographic recording medium to provide a visually perceptible image indicative of irradiation impedance characteristics of the tissue in an areal field of exposure of the tissue and simultaneously to provide a qualitative radiological visual reference representation of the test material of the tab, so as to establish objective and reliable indicia of the quality of a mammogram derived from a diagnostic mammographic procedure carried out.