Direct-positive silver halide photographic sensitive materials

A process comprising developing a direct-positive silver halide photographic sensitive material containing a silver halide emulsion layer with an alkaline infections developer solution containing hydroquinone as single developing agent, characterized in that (1) the silver halide emulsion is an externally fogged direct-positive silver halide which contains not less than 70 mole % of bromide, and at least one anionic cyanine dye having a polarographic oxidation halfwave potential of not less positive than +0.3 V and (2) a development accelerator is incorporated in at least one of the layers constituting the silver halide photographic sensitive material, said development accelerator being selected from the group consisting of

• (1) 2-mercaptoimidazoline and its derivatives of the general formula ##STR18## wherein R.sub.11 and R.sub.12 each represents hydrogen atom or an alkyl group having 4 or less or carbon atoms (for example, methyl and ethyl radicals), A represents oxygen atom, two hydrogen atoms, or one hydrogen atom and an alkyl group having 4 or less carbon atoms,
• (2) 2-mercaptoimidazole and its derivatives of the general formula ##STR19## wherein R.sub.13, R.sub.14 and R.sub.15 each represents hydrogen atom or an alkyl group having 4 or less carbon atoms,
• (3) 2-mercaptobenzimidazole and its derivatives of the general formula ##STR20## wherein R.sub.16 represents hydrogen atom or an alkyl group having 4 or less carbon atoms,
• (4) 2-mercaptotriazole and its derivatives of the general formula ##STR21## wherein R.sub.17 represents hydrogen atom or an alkyl group having 4 or less carbon atoms, R.sub.18 represents hydrogen atom, an alkyl group having 4 or less carbon atoms, allyl group or a group represented by the formula NH-R.sub.19, where R.sub.19 represents hydrogen atom or an acyl group having 4 or less carbon atoms (for example, acetyl group or propionyl group),
• (5) 2-mercaptothiazoline and its derivatives of the general formula ##STR22## wherein R.sub.20 and R.sub.21 each represents hydrogen atom or an alkyl group having 4 or less carbon atoms,
• (6) 2-mercaptothiazole and its derivatives of the general formula ##STR23## wherein R.sub.22 and R.sub.23 each represents hydrogen atom or an alkyl group having 4 or less carbon atoms, and
• (7) 2-mercaptothiadiazole and its derivatives of the general formula ##STR24## wherein R.sub.24 represents hydrogen atom, an alkyl group having 4 or less carbon atoms, or a group represented by the formula NH-R.sub.25, where R.sub.25 represents hydrogen atom or an alkyl group having 4 or less carbon atoms.