The Influence of Heat on the Sensitivity of a Photographic Film to Low Intensity Light

A fast radiation monitoring film, the lIford PM I, was exposed at 0 per cent relative humidity to low intensity u-v light from a plastic scintillator, the exposure temperoture being varied between +10 and +75°C. Films were also heated at 60°C. and 0 per cent RH and subsequently exposed to the scintillator light at 30O°C, the results indicating the presence of latent sub-image in the heated film at the end of the heating. From the temperature dependence of the net film density obtained with constant heating time the activation energy of 126 eV was derived, this corresponding to the formation energy of a Frenkel defect in silver bromide. The results suggest that the effect of increased temperature in increasing light absorption is a minor one in this instance.