Variation of Photographic Sensitivity with Development Time
Raymond Davis, Gerald Kent Neeland · Journal of the Society of Motion Picture Engineers · 1932
The relation between photographic sensitivity and the time of development has been studied. Three modifications of Hurter and Driffield's method of measuring plate speeds have been used as indexes of sensitivity. The results are generally in accord with those of Bullock, who investigated the relation of “threshold speed” to development time. An optimum time of development is indicated, which varies with the type of emulsion. — The differences between the three indexes have been brought out. Just which index is most satisfactory depends somewhat on the nature of the individual problem. It is concluded that, in many cases, a single value of any index is inadequate to represent the sensitivity of a given emulsion. The clearest representation may be had by a curve plotted between a sensitivity index and development time.