Unexplained Complex Colour shifts within Single and Dual wavelength holograms

摘要

True Colour holography is enjoying a resurgence through the commercialization of both new materials and Diode lasers which combine to produce an interesting number of commercial opportunities. This paper points out an unusual colour shifting on Bayfol HX photopolymer primarily. Later, Geola GP3C photopolymer is also tested for the colour shifting property. Two different images are recorded on silver halide material using two different wavelengths 660nm and 532nn to generate bright silver halide masters. The Bayfol photopolymer was then used to copy the images from the masters which were index matched. An unusual colour shift in photopolymer material, from green to red, using a single-wavelength laser (532nm in this case) to combine different holograms recorded with different reference angles was noted, which means it is possible to reconstruct a hologram, or information, from another pre-recorded object, apparently reconstructing at another wavelength to that of the original. It was possible to capture two different images(information) index matched and placed at 180~0 to each other at two different wavelengths by using only one laser in reflection mode geometry. This paper summarises how this effect is caused and under what circumstances this occurs.