Intrinsic properties of holographic recording materials: principles and devices used for an objective evaluation

P.-Y. Berken
University of Liège, Belgium
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As the best holographic recording material can lead to bad holograms if recording and development conditions are not optimal, we need an objective evaluation of the quality of these holographic recording materials. A coherent suite of methods enabling an evaluation as objective as possible of these materials is presented. These methods are designed for a silver halide emulsion characterisation but some of them can be used for other materials. When needed, devices have been built to permit rapid and maximum human handling free characterisation. By this mean we first determine the characteristic curve (the so called Hurter and Driffield curve) of the emulsion for any needed visible wavelength. Ten partial characteristic curves can also be recorded in a single exposure to lead to a spectral sensitivity curve. In addition we can provide the emulsion normalised modulation transfer function (MTF) thanks to an easy to build and use device. Finally a transmission electron microscope and an X-ray diffractometer are used to measure the silver halide grain size of the emulsion. Extended practical considerations are given for each of these methods. Results obtained by the developed methods on a commercial Fuji holographic film are presented.