Theoretical Considerations on the Quantum Efficiency of Photographic Detectors*

The relation of theoretical characteristic curves for monolayer ensembles of go-no-go detectors (emulsion grains) to quantum efficiency is developed. It is shown that the statistical fluctuations in the incident photons, as well as the fluctuations in the number of detectors made developable by a given exposure, preclude the possibility of achieving a quantum efficiency of unity. The maximum quantum efficiency achievable depends on the number of photons required for developability as well as on the exposure. The latitude requirements for such an ensemble impose further restrictions on the achievable quantum efficiency.