A systematic study has been carried out to assess the x‐ray attenuation properties of various elements when used as radiographic contrast enhancing media. This study examines the effects of solutions of molecules with effective atomic numbers from 40 to 92 on the signal–contrast ratio of radiographic images formed with various input x‐ray spectra on suitable phantoms. A variety of x‐ray spectra were used including monoenergetic spectra, constant potential x‐ray tube spectra, and computed tomography spectra. In addition, a computer model was used to predict the effects studied. In general, the computer model is able to accurately predict the resulting signal–contrast ratio for a given combination of contrast media, input x‐ray spectra, and phantom composition. From these data and calculations, it may be possible to design new contrast media which are tailored to specific diagnostic imaging tasks.