A simple method of producing diagnostic copies from overexposed radiographs.

Overexposed radiographs that have density measurements greater than three can yield diagnostic copies. An unexposed standard radiographic film is sandwiched between a completely black film and the film to be copied in a cassette with standard-speed rare earth intensifying screens. The fluorescence of the unblocked intensifying screen, induced by a measured x-ray dose from an x-ray machine, is the light source that exposes the film, yielding a negative copy. The negative can also be copied to produce a positive-phase radiographic image. The high degree of contrast achieved by this copy method regains the contrast scale that is lost on overexposure. It is capable of enhancing faint calcification and other low-contrast features of soft tissues.