containing developing agents underwent serious reduction in transferred silver density under the incubation condition on the other hand samples 5 to 7 containing the compounds of the present invention underwent only a slight reduction in transferred silver density while maintaining their sensitivity at a high level d 1 and d 3 are the same as used in example 1 str11 in order to evaluate the effectiveness of the developing agent precursors of the present invention in comparison with control comparative compounds developing agents or precursors thereof given in table 4 were dissolved in dibutyl phthalate and ethyl acetate to emulsify and added to emulsions followed by coating each of the emulsions on a subbed cellulose triacetate film support to prepare samples 20 to 24 the amounts of respective substances coated were indicated im parentheses as numerical values in terms of g m 2 or mol m 2 negative type silver iodobromide solution grain size 0 6 u03bc silver 2 5 u00d7 10 2 mol m 2 developing agent or its precursor 1 33 u00d7 10 3 mol m 2 these films were left for 14 hours at 40 u00b0 c and 70 rh then imagewise exposed for conducting sensitometry and subjected to the following black and white development ______________________________________ time temperatureblack and white developing step min u00b0 c ______________________________________1 black and white development 4 202 stopping 1 34 3 fixing 10 34 4 washing with water 10 34 ______________________________________ the compositions of processing solutions used in the black and white processing steps are as.