Two parameters are discussed: (1) the orientation of the plate assembly, consisting of the original hologram and a copy plate, relative to a laser copying beam, and (2) the separation between the original hologram and the copy plate. The data presented demonstrate that the optimum arrangement for the production of hologram copies requires that the plate assembly be held in vacuum contact, and that the laser copy beam enters the plate assembly in the reference beam direction of the original hologram. These optimum copies display reconstructed virtual images identical in angular extent and similar in quality to those reconstructed from the original. Copies made at angles other than the optimum angle display only certain portions of the original scene. The portion of the scene displayed is related to the copy angle and the angle in which light was scattered when the original hologram was exposed.
M. J. Landry, "The Effect of Two Hologram-Copying Parameters on the Quality of Copies," Appl. Opt. 6, 1947-1956 (1967)