acid), a pH buffer (e.g., sodium tertiary phosphate, sodium carbonate, potassium carbonate, sodium metaborate, and lithium tetraborate), an inorganic antifoggant (e.g., sodium bromide and potassium bromide), an organic antifoggant (e.g., 1-phenyl-5-mercaptotetrazole and 5-nitroindazole), an organic solvent (e.g., ethylene glycol, diethylene glycol, and methyl cellosolve), a color toning agent, a surface active agent, a defoarning agent, a hard water softener, etc., in addition to the foregoing components in the range of not reducing the effects of the invention. 

The processing temperature of the developer of the present invention is in the range of from 18° C. to 50° C. and preferably from 20° C. to 40° C. 

As a fixing solution for use in this invention, a compo› sition generally used can be used. For example, the fixing agents described in Shashin Kogaku no Kiso, Gin-en Shashin Hen (The Foundation of Photographic Engineering, Silver Halide Photography), page 330 and below, edited by Nippon Shashin Gakkai, published by Corona Publishing Co., Ltd., 1979; Akira Sasai, Shashin no Kagaku (Chemistry of Photography), page 320 and below, published by Shashin Kogyo Shuppan Sha, 1982; and W. Thomas, Jr., SPSE Handbook of Photographic Science and Engineering, page 528, published by John Wiley & Sons, 1973 can be referred to. 

As the fixing agent, thiosulfates, thiocyanates, and organic sulfur compounds which are known to have the effect as a fixing agent can be used. Also, as an auxiliary fixing agent, an acid agent (e.g., acetic acid and citric acid), a preservative (e.g., sodium sulfite), a buffer (e.g., boric acid), and a hardening agent (e.g., potassium alum, alumi› num alum, and aluminum sulfate) can be used for the fixing solution. 

Then, the invention is explained more practically by following examples but the invention is not limited to the examples within the scope of the present invention. 

By simultaneously adding an aqueous silver nitrate solu- tion and an aqueous solution of a mixture of potassium bromide and sodium chloride (Br:Cl=30:70 by molar ratio) containing sodium hexachlororhodate(III) in an amount of l.5x10- $^{7 }$mol per mol of silver to an aqueous gelatin solution kept at 40° C. while keeping pAg at 7.2 over a period of75 4 minutes, a monodispersed silver chlorobromide emulsion (AgC170 mol %) containing the cubic crystal silver halide grains having a mean grain size of 0.28 µm was prepared. Then, after removing soluble salts by an ordinary method, 5x10- 5 mol of sodium thiosulfate per mol of silver halide was added to the emulsion and the emulsion was subjected to chemical ripening at 50° C. for 100 minutes. The silver halide emulsion obtained contained 80 g of gelatin per mol of silver halide. 

After adding thereto 6x10- $^{3 }$mol of 6-hydroxy-4-methyl- l,3,3a,7-tetraazaindene per mol of silver halide, the silver halide emulsion was split into two portions. To one of the split emulsions was added no sensitizing dye and to another split emulsion was added a sensitizing dye (D-18, reduction potential -1.24 volt) at 8,000xl0---6 mol per mol of silver halide, and each of the split emulsions was coated each of polyethylene terephthalate bases each having a subbing layer at a silver coverage of 40 mg/dm 2 • Then, a gelatin protective layer containing formaldehyde and dimethy› lolurea as hardening agents was coated on each emulsion layer followed by drying to provide film sample No. 1 (using the emulsion containing no sensitizing dye) and film sample 

## EXAMPLE 1 

No. 2 (using the emulsion containing the sensitizing dye). 

After exposing each of the film samples thus prepared to a tungsten lamp of 2666° K. using an LB-200 filter through a step wedge having a step difference of 0.15 for 5 second, each sample was developed with each of developers 1, 2, 3, and 4 having the following compositions, stopped, fixed, washed, and dried. t,1060 

The photographic characteristics obtained are shown in Table 1. t,1080 

In the above table, the relative sensitivity was the relative value of the reciprocal of the exposure amount of giving density 3.0 of the sample being evaluated from which fog was subtracted with the sensitivity of film sample No. 1 in Test No. 1 developed with Developer 1 for 5 minutes at 20° C. being defined as 100. The gamma was shown by the mean slope between the densities 0.5 and 3.0 from which fog was subtracted and the fog was shown by the density at the unexposed area. 

As is clear from the results shown in Table 1, when the film sample containing a large amount of the dye having a negative reduction potential satisfying the factor of the present invention is developed with the developer containing the arninophenol derivative developing agent and the reduc- tone compound, remarkably high sensitivity and high con› trast are obtained. However, when film samples are devel› oped with Developer 2 (Kodak D-11 Formula; High› Contrast MQ Developer) described in Akira Sasai, Saishin Shashin Shoho Binran (Newest Photographic Formula Handbook), published by Shashin Kogyo Shuppan Sha, 1983, Developer 3 (FD-185 Formula, by Fuji Photo Film Co., Ltd,; Lith Type Developer), or Developer 4 (a developer formula for super high-contrast development using the hydrazine derivative), a high contrast is not obtained and a remarkably high sensitivity is not obtained even when a large amount of the dye having a negative reduction poten- tial is incorporated in the film samples. 

The foregoing phenomenon of obtaining a high sensitivity and a high-contrast by the dye having a negative reduction potential has not been known until now and an utterly new fact discovered by the inventors. 

By simultaneously adding an aqueous silver nitrate solu› tion and an aqueous solution of a mixture of potassium bromide and sodium chloride (Br:Cl=30:70 by molar ratio) containing sodium hexachlororhodate(Ill) in an amount of l.5x10- $^{7 }$mol per mol of silver to an aqueous gelatin solution kept at 40° C. while keeping pAg at 7.2 over a period of 75 minutes, a monodispersed silver chlorobromide emulsion (AgCl 70 mol %) containing the cubic crystal silver halide grains having a mean grain size of 0.28 µm was prepared. After removing soluble salts therefrom by an ordinary method, 5x10-s mol of sodium thiosulfate per mol of silver halide was added to the silver halide emulsion and the emulsion was subjected to chemical ripening for 120 min› utes at 52.2° C. The silver halide emulsion obtained con› tained 80 g of gelatin per mol of silver halide. Then, after adding to the emulsion 6x10- $^{3 }$mol of 6-hydroxy-4-methyl- 1,3,3a,7-tetraazaindene per mol of silver halide, the emul› sion was split into many small portions. Then, after adding to each of the split portions each of the dyes or the pyridinium salt derivatives shown in Table 2 below and each of the polyalkylene oxide derivatives and each of the dyes or the pyridinium salt derivatives shown in Table 3, each emulsion was coated on a polyethylene terephthalate (PET) 

## EXAMPLE2 

