To obtain a processing member for heat development capable of forming a monochromic image having a high maximum density, low minimum density, good sharpness and high image quality in a short time by using a specified compound as a precursor of a silver halide solvent.
A compound of the formula or the like is used as a precursor of a silver halide solvent. In the formula, R1 and R2 are each H, an aliphatic hydrocarbon, aryl or -(L1)n-Y1, R3 is H, an aliphatic hydrocarbon, aryl, acyl or the like or -(L1)n-Y1, Y1 is a silver halide solvent, L1 is a divalent combining group, (n) is 0 or 1, X is a group of atoms required to form a 5- or 6-membered ring by combination with -N-C-S- in the formula and at least one of R1-R3 is -(L1)n-Y1 or the group of atoms X is substituted by at least one -(L1)n-Y1.
KOJIMA TETSUO
SHIBATA TAKESHI
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