2014 Second prize
One colored image can lead to different color impressions, depending on the colourless luminance profile that is presented on top of the colored image. In all versions of the illusion, the underlying colours are identical. However, the grey scale image that is presented on top of the colored image reinforces the colors that are congruent with the the gray scale image and inhibits incongruent colors. As a result the color impression is very different for the different images. This illusion is a demonstration of how in our brain color and contour information is combined before the eventual perception is determined.