Optimization of fixation-free rehalogenating bleach for BB-640 holographic plates

Abstract

Fixation-free rehalogenating bleaching is an interesting process for the production of phase holograms. The shrinkage of the emulsion is reduced in comparison with other bleaching methods (reversal bleaching or rehalogenating bleaching with fixation). In this paper we present experimental results for fixation-free rehalogenating bleached holograms derived from the novel BB- 640, a red-sensitive ultra-fine grain emulsion from Holographic Recording Technologies. The influence of the Potassium bromide concentration in the bleach solution on the final quality of the holograms is also studied. The concentrations of the different components of the bleach solution are adjusted to obtain the highest values of the diffraction efficiency. We studied transmission and reflection fixation-free bleached holograms. We will show that really high diffraction efficiencies can be obtained, as high as 87% for transmission bleached holograms recorded on BB-640 plates, and 72% for reflection bleached holograms.