When certain scenes are stored on photographic emulsions, the Fraunhofer diffraction pattern of these scenes exhibits an array of equally spaced bright spikes along the axes that are not accounted for by simple theory. Experimental evidence, obtained with random-checkerboard patterns, supports the proposed theory that these higher orders result from interaction of the stored density variations and the induced relief image in the emulsion.
H. Stark and F. B. Tuteur, "Higher orders in the diffraction pattern of random scenes in coherent optical systems," J. Opt. Soc. Am. 63, 675-685 (1973)