[onoway]

a change of pace but this seemed interesting..no explanation why this works as it does, though. http://www.joe-ks.co...ingIllusion.htm

[gwnn]

awesome stuff

[helene_t]

If you focus on the black cross, your eyes become calibrated to pink dots, so what you see is the residual relative to pink dots, which is green in the absence of the pink dot, since
white - pink = green

It is essential for our sight that the our eyes work that way. We notice deviations from the baseline light rather than absolute light reflected by an object. A red tomato looks red no matter if you see it in the shade, in artificial light, in noon sunlight or at dusk. We aren't even conscious that the light reflected by the tomato is completely different under different circumstances.

[bb79]

Instead of simply red green blue channels, human visual perception is better represented the following three components: luminance, blue-yellow, red-green channels. It is called opponent color model.
http://en.wikipedia.or/wiki/Opponent_process .

The example Helene gave about the color of tomato is rather related to color constancy :
http://en.wikipedia....Color_constancy

[effervesce]

This one is my all-time favorite illusion

Checkershadow illusion

[barmar]

Yeah, the checkershadow is great. I can stare at that for ages and not break the illusion. Even when the stripes are added for proof it's hard to see it -- my eyes keep trying to add gradients to the stripes.