Effect of scattered light on extent of border enhancement

A contrast border, formed where 2 uniform fields of differing luminance meet, was viewed through filters containing a scattering agent. The filters resembled the cornea and crystalline lens in that the amount of light scattered increased exponentially toward the direction of the indicent light. The perceptually enhanced regions on both sides of the border were measured for various concentrations of the scattering agent. Measurements were obtained for several luminances of the brighter field, the darker field remaining constant. It was found that the width of the enhanced region, both on the bright and on the dark side of the border, increased approximately linearly with the logarithm of the amount of light scattered. The increase was of approximately the same order for all of the luminances tested.