Method for producing a long scale direct-positive photographic emulsion

A method of making a chemically fogged direct-positive silver halide emulsion by a process of double jet fogging, in which process a stream of unfogged silver halide emulsion is continuously pumped from a supply vessel to a receiving vessel, and at the same time a stream of chemical foggant is continuously pumped into said receiving vessel over an extended period of time, whereby the silver halide grains of said emulsion are fogged to a continuously varying degree and exhibit a multitude of photographic sensitivities within the same emulsion, whereby a Density vs. Log of Exposure curve of said emulsion coated on a support provides extended exposure latitude and exhibits no discrete steps.

A method of making a chemically fogged direct-positive silver halide emulsion by a process of continuous quenching, which process comprises providing a supply vessel containing silver halide emulsion, supplying a chemical foggant to the emulsion in said supply vessel while maintaining the temperature of the vessel at about 73.degree. C., whereby chemical fogging of the emulsion is initiated, continuously drawing off partially fogged emulsion from said supply vessel over an extended period of time and transferring it to a receiving vessel, and maintaining the temperature of the receiving vessel at about 35.degree.-48.degree. C., whereby the chemical fogging of the emulsion is quenched, whereby the silver halide grains of said emulsion are fogged to a continuously varying degree and exhibit a multitude of photographic sensitivities within the same emulsion, whereby a Density vs. Log of Exposure curve of said emulsion coated on a support provides extended exposure latitude and exhibits no discrete steps.

A method of making a chemically fogged direct-positive silver halide emulsion by a process of continuous quenching, which process comprises providing a supply vessel containing silver halide emulsion, supplying a chemical foggant to the emulsion in said supply vessel while maintaining the temperature of the vessel at about 73.degree. C., whereby chemical fogging of the emulsion is initiated, continuously drawing off partially fogged emulsion from said supply vessel over an extended period of time and transferring it to a receiving vessel, and continuously adding a quenching solution to the stream of partially fogged emulsion at a point between the supply vessel in which said emulsion stream originates and the receiving vessel, whereby the silver halide grains of said emulsion are fogged to a continuously varying degree and exhibit a multitude of photographic sensitivities within the same emulsion, whereby a Density vs. Log of Exposure curve of said emulsion coated on a support provides extended exposure latitude and exhibits no discrete steps.