PURPOSE: To have high developability and to decrease the deterioration in photosensitivity in long-period preservation by incorporating specific platy photosensitive silver halide particles at 0.05W1mol for each 1mol org. silver salt into a photosensitive silver halide emulsion layer.
CONSTITUTION: The photosensitive silver halide emulsion layer of the heat developable photosensitive material contains the platy photosensitive silver halide particles having 4W40mol% silver iodide content and ≥5 ratio of particle thickness with regard to particle size at 0.05W1mol by 1mol org. silver salt. The grain size of the silver halide particles is preferably 0.05W4.0μm grain size and the thickness of the particles is preferably smaller than 0.3μm. The shelf life is good but the developability is poor if the content of the silver halide particles is ≤0.05mol by 1mol org. silver salt. The developability is good but the shelf life is poor in the case of ≥1mol. The amt. of the org. silver salt to be used is preferably 0.001W50g by 1m2 per layer.
OKAUCHI KEN
KONO JUNICHI
IWAGAKI MASARU
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