A survey of radiographic films to establish the best donor/receiver combination for use in the autoradiographic image intensification technique was studied. Underexposed images of a 16 step aluminum wedge and a resolution target were made with Kodak film types XG-1, XL-5, XV-2, NMC or DuPont Cronex film. The underexposed, developed and processed films were treated in a subtractive photographic reducer (mixture of potassium ferricyanide and sodium thiosulfate) prior to radioactivation with an alkaline solution of sulfur-35 thiourea. Autoradiographs of the radioactivated films were made. Both qualitative and quantitative evaluations of the intensified images and their corresponding characteristic D-Log Rel. H curves indicate that Kodak films XG-1 and NMC formed the best donor and receiver combination. Statistical analyses of the quantitative results confirmed the choice of the XG-l/NMC combination as the best donor and receiver respectively. The use of sulfur-35 thiourea with high specific activity for activation of the underexposed image yielded disproportionate activation in the low and high density areas. Use of low specific activity sulfur-35 and potassium ferricyanide during the activation process seemed to indicate that linear activation of the underexposed step wedge can be achieved
