Archive for June 16, 2019

The Coloured Ball Illusion

Posted in Art on June 16, 2019 by telescoper

This image, created by David Novick, is the most impressive colour illusion I have ever seen: all the balls are actually the same colour, brown.

If you don’t believe me, zoom in on any one of them…

I don’t really know why this fascinating image causes the effect that it does, but think it is a combination of hardware and software issues! The hardware issues include the fact that colour receptors are not distributed uniformly at the back of the human eye, so colour perception is different when peripheral cues are present, and also that their spectal response is rather broad with considerable overlap between the three types of cell. The software issue is something to do with how the brain resolves a colour when there are other colour nearby:nNotice how the balls take on the colour of the lines passing across them..

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