Abstract: Novel method of free radical photography in which a colored image excellent in photographic properties such as gradient, resolving power, image stability, amount of fogs and contrast can be obtained while shortening the treating time and simplifying the treatment steps. The method comprises exposing a photosensitive composition comprising a film-forming transparent plastic, a compound capable of forming free radicals upon irradiation with light and a color former capable of reacting with these free radicals to produce color, to a light flash with a light quantity of 5 to 500 millijoules per square centimeter for a flashing time of 0.0001 to 0.005 second through a negative or positive original.