Reversal bleaching for low flare light in holograms.

It has been shown that the principal cause of flare light in a bleached hologram is self-interference of light from an extended object. In most bleaching processes the surface relief image and variation of refractive index of the bleached emulsion combine to enhance the self-interference pattern at low spatial frequencies and thus to enhance the flare light. This paper describes a reversal bleach process for Kodak spectroscopic plates, Type 649-F, such that the relief image tends to cancel the effects of the index variation for low spatial frequencies. This makes it possible to achieve high diffraction efficiencies and signal-to-noise ratios. Data are given.