Quote Originally Posted by BentleyR View Post
We sometimes use volume diffraction gratings to create a sample of the optical wavefront we want to measure. These gratings are very similar in structure to a finished Lippmann plate being formed by three dimensional index variations in a transparent medium. They are typically made using materials like the photopolymer mentioned in holmburgers recent post or from photochromic glass. These aren't suitable for the Lippmann process because they require quite intense optical beams for creation (i.e. lasers).
Actually, the speed of the photopolymers mentioned above by holmburgers comes much closer to that of an AgX Lippmann emulsion than photochromic glass. So yes, they can be used for Lippmann photography. Another question though is: would there be enough demand to (commercially) justify the production of such films.
Probably the highest index modulation, diffraction efficiency (= image brightness of a Lippmann photo) could be achieved if the recording materials were to be contacted with a mirror/reflector. Principally, this implies a sandwich structure: transparent film substrate-recording layer-mirror/reflector. The above mentioned photopolymers films (photopolymer on polyester film) were optically contacted with an aluminized Mylar film. After the light exposure that reflector film was peeled off.