Brightness perception in complex fields.

Results of brightness-scaling experiments with complex stimulus fields are reported. A family of brightness functions has been computed from the data for complex stimuli such as photographic reproductions viewed with both iluminated and dark surrounds. The resulting brightness vs luminance-functions are not simple power functions. The exhibit exponential decay from the power form as a function of both screen luminance and surround luminance; i.e.the are nonlinear in log-log coordinates.