Infrared presensitization photography

Infrared presensitization photography (IRPP) is a double exposure technique that allows the recording of IR information on standard silver halide films not ordinarily sensitive in this long wavelength regime. This dissertation prescribes conditions for the practical implementation of the IRPP process in data collection. It then moves on to an investigation of mechanism; i.e., why does IRPP work? The study is divided into experimental and theoretical portions, with much heavier emphasis on the former. Experiments delve into the behavior of the characteristic and spectral sensitizing curves of film within the context of the IRPP phenomenon. The temperature rise experienced by the film during this process is determined. The influence of sensitizing dyes and ionic population increases in the grain crystals is also explored. Theoretical efforts concentrate on an extension of the shaw photographic model to explain the IRPP effect in terms of a downshifting in the overall quantum sensivitity requirements of the grain population.