| 摘要 |
High-speed direct positive silver halide emulsions characterized by improved densities and highlights are prepared containing a combination of a strong inorganic chemical fogging agent and an organic reducing agent and/or its oxidized form taken from the group consisting of methyl-p-aminophenol (metol), hydroquinone, quinone, quinhydrone, 1,4-naphthalenediol and 1,5-naphthalenediol, and an alkali metal sulfite, said combination being in an inert environment where it is unable to cause the formation of chemical fog centers or sensitivity centers on the silver halide grain surfaces before exposure and processing. Such an environment can be established by adjusting the pH range between 4.9 and 6.5.
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