To appear in a new light: Varying illumination colors induce dynamic transformations of perceptual qualities in still images.

We demonstrate that dynamic illumination color variations can trigger surprising changes in perceptual qualities for printed imagery. We explored different types of printed stimuli, including existing illusions with color patterns, contrast phenomena, colored materials and objects, and art. Stimuli were presented under color-changing illumination, and naive observers were asked to report whether they saw any qualitative changes, and if so, of what type they were. Observers reported a wide variety of effects, ranging from glowing, deforming, wiggling, rotating, and flowing, to changes in depth or material. These results show how varying lighting color can modulate not only color appearance and contrast per se, but can also induce more general changes of object appearance in still images.