"Folded film" is an experimental technique of film preparation that provides diagnostic imaging of intraoral structures with one-half the radiation required to produce conventional images. In this study, folded film periapical images were compared with similar conventional D- and E-speed film images with the use of 12 criteria for diagnostic visualization. Nineteen examiners judged folded films to be slightly less diagnostic than D-speed film images and somewhat more diagnostic than E-speed films. All systems were judged adequate for diagnostic visualization of bone and teeth.