In a photographic printing process, the granularity mottle which represents the printed-through granularity pattern of the negative can be analyzed best by means of the Weiner spectrum of its density fluctuations. A theory is given for the linear transfer of granularity through a printing process, and results are given for a series of optical and contact prints. The case of mottle arising in x-ray screen exposures is similar; it is shown that the measuring techniques will evaluate the effects of various screens.
EDWARD C. DOERNER, "Wiener-Spectrum Analysis of Photographic Granularity," J. Opt. Soc. Am. 52, 669-672 (1962)