The Theoretical Limits of Photographic Sensitivity
E. Klein · The Journal of Photographic Science · 1962
A survey is given on the statistical theory of the H. & D.-curve recently published by Frieser and Klein. Shape (gradation) and position of the toe of the "elementary" (single-grain emulsion) H. & D.-curve are determined by the poisson-distribution of the incident quanta, the sensitivity spread of the grains and the grain size distribution. Examples of calculated H. & D.-curves are shown. Emphasis is put on the demonstration, that it leads to erroneous results when experimental H. & D.-curves are compared merely with sensitivity distribution curves. For comparison the size distribution must be token into account. It is confirmed that grains exist which become developable after the absorption of 4 quanta. It is concluded that with emulsions consisting entirely of grains which become developable after the absorption of just one quantum the practically exploitable sensitivity of the emulsions could be increased by a factor of about 10.