My bathroom has a bank of incandescent light over the sink and a red heat lamp in the middle of the ceiling. Go into it at night and turn on the white light. Find a place that the white light shines on, but is in the shadow of the red light. Right next to a door jamb gives the most surprising effect. Look at that place and turn on the red light. The area in the shadow of the red instantly turns pale green. Turn off the red light and it reverts. Repeat as often as you like. Really impressive. Maybe it would work with a flashlight covered with red cellophane.
The most fascinating of these phenomenon that I have read about recently is at Do People Always See the Same Things When They Look At Colors? if I got it linked properly.
Do note that, as pointed out in the comments, no green square is actually more different than the others because of JPEG compression. Also, the premise is faulty, because most people can easily distinguish different colors even though I can’t actually name them. The study I’m familiar with involved memory–the participants could tell the difference if the different colored objects were placed side by side, but not in succession, and accuracy decreased the longer between the display of both objects.
As for the OP’s effect: I’ve seen it many times, and have always wondered about it. I’ve seen it be rather bright, which makes it seem unlikely that it’s just an optical illusion.
Green and Blue Photos | Green and Blue Pictures - Yahoo! Games is one that was published recently. I cannot determine how long the illusion has been know.
I don’t understand this picture. So if I opened this in Photoshop and used the eyedropper tool on the blue and green sections it would come up as the same color?
It doesn’t.
I’m not sure I understand what you mean that it’s unlikely to be an optical illusion. The evidence is that if I shade a large area the effect disappears. It is only by contrast to the pink areas (which look white) that the shaded areas (which are white) look green.
I just did exactly that and they did.
Ok, you’re somewhat right - I am sure that in the original picture they were the same. The one that was linked to was a JPEG, which because of compression has scrambled the colors, especially changing the border ones. But right in the middle of the wide sections - yes, the colors are basically the same - FF8CFF or thereabouts.
That’s a bad illustration of the effect, since most of the pixels’ colors in those bands are not the same in the picture except right in the middle of the band. They should have left it as a GIF or something.