Experimental measurements show that the phase transmittance characteristics of a photographic material, caused by relief images and variations of refractive index, can be fairly reproducible if processing is properly controlled. To manipulate these characteristics, particularly those of bleached materials, it would be desirable to have data for the phase image corresponding to the density-log exposure curve and the MTF curve of the density image obtained by conventional processing. A method is described for obtaining both curves from measurements of optical path variation of sinusoidally exposed images. Components from both the relief image and the variation of refractive index can be determined. It is shown that such data for a bleached photographic material can be used to produce an optical path variation having an arbitrary profile.
Robert L. Lamberts, "Characterization of a Bleached Photographic Material," Appl. Opt. 11, 33-41 (1972)