Abstract: The fog development of silver halide emulsion with sensitizers of of sulphur and gold indevolopers D-19b and CD-4 were studied.The experimental results showed that the fogdensity produced by both sensitizers of sulphur and gold in D-19b developer is greater thanthat in CD-4 one,Moreover,in some sulphur levels the fog produced by sulphur sensitization is much larger than that gold sensitization in the developer D-19b,and whereas it issmaller in the developer CD-4 in comparison with that by the same gold level sensitization.These results were in consonant with the study of the fog developing dynamics of sulphurand gold sensitization in the developers D-19b and CD-4.These results indicated that sulphur sensitization is distinctly diffrent from gold one for the influence on the fog formation in the fog developing processes.The fog formation rate constants of the emulsion with the sensitizer of sulphur is greater than one with sensitizer of gold,and the fog development activation energy of the emulsion with sensitizer of sulphur is smaller than one with the sensitizerof gold in the developer D-19b.Conversely,the fog formation rate constants of the emulsionwith sensitizer of sulphur is smaller than one with sensitizer gold,and the fog development activation energy of the emulsion with sensitizer of sulphur is greater than one with sensitizergold in the developer CD-4.

Key words: silver halide microcrystal, sulphur and gold sensitization, fog development, activation energy To whom correspondence should be addressed.