Hue perception under scotopic light levels

Results A 1 deg test ring was viewed at a 7 deg retinal eccentricity on a CRT covered by neutral density lters. The test luminance was approximately -2.6 log scotopic cd/m2 (-4 log photopic cd/m2) . The test ring was surrounded by either 2 (simple context both equal luminance, either higher or lower than test) or 4 (complex context 2 higher, 2 lower luminance than test) 1 deg inducing rings. Stimulus duration (4 temporal presentations), inducer spacing (3 conditions) and contrast (4 conditions) were varied for both simple and complex context. A hue scaling technique was used to measure perceived hue and saturation. Complex Context