I suspect this happens because the cones (which detect colour and are more sensitive than rods) are concentrated in the middle of the retina, and the colour leaves an after-image on the retina that appears on the black and white image for a moment.
Yep, the "fatigue" factor. You see the reverse color for a few moments. Voila a colored castle. Nice effect.
And the staring at the dot is just to make sure that the two images superimpose. Otherwise it doesn't work because the color ghost image is pretty faint.
We used to do these all the time without the B&W image behind it. They'd do an American flag in green, black & orange, and you'd see it correctly on any white surface for a moment. The B&W gives you better detail, and apparently help in not moving your eyes and eliminating the "fatigue" that makes the image persist.
It's also demonstrating the point that the colour you see in your peripheral vision is almost entirely a construction of the brain, rather than a response to the wavelength of light.
![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
no subject
no subject
no subject
And the staring at the dot is just to make sure that the two images superimpose. Otherwise it doesn't work because the color ghost image is pretty faint.
Yup
(Anonymous) 2006-06-09 05:56 pm (UTC)(link)no subject
no subject
Try looking away for about 15 seconds and then back.
My brain, when I look at the dot on the black and white picture, wanted to paint in the color for quite a while afterward...
no subject
no subject