Abstract: A model of computer simulation measurement of the granularities with circular sampling aperture is used for studying the granularities of the image layers which are obtained from the corresponding patterned silver halide layers. The results show that a variation in circular sampling aperture size may cause much less fluctuation of the granularity values measured, i.e. which may be more steady, than that in square sampling aperture size. In addition, it is also shown that all patterned layers have the same variation trend versus density.