Methylene blue sensitized dichromated gelatin holograms: influence of the moisture on their exposure and diffraction efficiency.

Dependence of the moisture of the plate on the hologram characteristics is studied for methylene blue sensitized dichromated gelatin. The maximum diffraction efficiency increases, and the exposure to obtain a certain amount of diffraction efficiency is reduced for the red light when the moisture of the gelatin layer is properly controlled during exposure. The photochemical reaction of the plate is briefly discussed, and the result of the double exposed hologram is also presented.