Patent Number: 063296624
Section: abstract

A radiation image forming system utilizing a combination of a silver halide photographic material and radiographic intensifying screens is improved in its radiographic speed and sharpness of the resulting radiation image by employing a rare earth phosphor of the formula M.sub.w O.sub.w X:M' (M is Y, La, Gd or Lu; X is a chalcogen atom or a halogen atom; M' is a rare earth atom which activates M; and w is 2 when X is a chalcogen atom or w is 1 when X is a halogen atom), incorporating into the intensifying screen a fluorescent dye or pigment which absorbs a portion of luminescence emitted by the phosphor and then emits light in a visible region, and employing a photographic material showing a cross-over of 10% or less when it is exposed to radiation in combination with the intensifying screens.