Abstract: The effects of heavy-atom compounds and atmospheres on the optical development rate of CBr₄-LCV(Leuco Crystal Violet)free radical filmhave been studied. It was found that the development rate is. increased inthe presence of heavy-atom compounds:CHI₃, p-iodoaniline and triphenyl-bismuth in the film or the optical development proceeds in nitrogen and is decreased when the film is developed in oxygen, indicating the possibi-lity of T-T energy transfer mechanism. The ratio of rate constant K₀ innitrogen to K in the mixture of N₂/O₂ follows the equation K₀/K=1+α[O₂]where α is the quenching constant. In the main period of the optical development the following relationship between optical density(D)and time(t)is also found to be existed D=D₀+Kt, where D₀ is the experimental constant, K and t are the optical development rate constant and time, respectively.