| 摘要 |
Direct-writing silver halide emulsions having higher maximum densities, lower background densities and increased image aging stability are prepared by precipitating silver halides in an acidified aqueous water-permeable colloid medium in the presence of a water-soluble plumbous salt, ripening the resulting emulsion in the presence of excess bromide ions, washing said emulsion to remove the soluble salts resulting from the precipitation of silver halides, adding a heterocyclic nitrogen compound and at least one acid anion capable of forming a substantially insoluble compound with lead ions, digesting the resulting emulsion, adding a halogen acceptor and coating the emulsion on a suitable support. The direct-writing, photodevelopable elements made from the emulsions are useful in oscillographs.
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