– Jose-Manuel Alonso: “Lights and Darks in Vision”. State University of New York, USA
This illusion demonstrates that the perception of dark and light features in a face is strongly influenced by context. A picture of a face is split into a dark-half and light-half version by setting either the light or dark pixels to a fixed gray value (while keeping the other pixels unchanged). The ‘white’ of the eyes in the dark-half picture has the same luminance as the ‘dark’ lips in the light-half version but the lips appear much darker. This strong illusion can be demonstrated with any face or visual scene photographed with a standard digital camera.