Processing method of black-and-white photographic materials

Details Processing method of black-and-white photographic materials Processing method of black-and-white photographic materials

1999-01-22

2000-08-15

Mathews, Alan A.

Photography

Fluid-treating apparatus

Having fluid-circulating means

396622, 396626, 430398, 204528, G03D 302

Patent

active

061025895

ABSTRACT:
A method of processing an exposed black-and-white silver halide photographic film material, the method having the steps of developing in a developer solution, fixing in a fixer solution, replenishing of fixer and developer solution, rinsing in a washing solution and drying, characterized in that fixing is performed in one step and under such conditions that a "silver equilibrium ratio" of less than 2.0 is maintained, the said ratio being defined as the ratio between actual by the film material in the rinsing step through carry-over (cross-over) of silver from the fixing solution to the washing solution and amount of silver brought into the washing solution and the total amount of silver that theoretically could be brought into the washing solution by the film material by such carry-over; a "fixer to film silver ratio" of less than 0.2 is obtained, this ratio being defined as the ratio between silver content in "running equilibrium condition of the fixer" and amount of silver in the film material to be fixed in the fixing step, wherein said "running equilibrium condition of the fixer" is the condition attained after having replenished said fixing solution twice. By this method an ecologically favourable minimization of silver content in the washing solution has been obtained without impairing the processing speed, without enhancing processing costs and without excessive regeneration.

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P J Mutter: "Silver Recovery Management For Motion Picture Laboratories", SMPTE Journal, vol. 93, No. 9, Sep. 1984, XP002071874.
Grant Haist: "Modern Photographic Processing", vol. 1, 1981, John Wiley, New York, XP002071875, pp. 563-566.

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