The Most Wicked Optical Illusion I've Seen So Far

This is sick. Sick because the spiral effect is making me sick and sick because it reminds me how flawed/awesome/trippy our color perception is. Believe it or not, the green and the blue in this spiral is the same color.


I couldn't believe it either, but I just measured the value in Photoshop: Red 0, Green 255, Blue 150 on both. Crazy. How could this be possible?

The reason why we are perceiving one color as different colors is because of the other colors surrounding the stripes. Each eye has six to seven million cones, which are concentrated in a central yellow spot known as the macula (I recently got mine lasered to fix some leaking blood vessels). These cones measure color in different wavelengths, overlapping in some of them. Our brain then compares those signals in an antagonistic manner, measuring differences in wavelengths between them. When some colors are combined, the brain can't process the info from the cones correctly and we simply get confused. [gsu and Techi]



It seems to me it's more an effect of those lines that run roughly perpendicular to the main spiral. If you look really closely (or in Photoshop, as I did), you'll notice the lines aren't continuous. Each main section offsets those lines by about 1 pixel. So what looks like a continuous pink line is really a line that alternates between pink and orange. Orange over the "green" sections and pink over the "blue" sections. (Actually, the pink lines start and stop at the edges of one green section to the next; the orange from the edge of one blue to the next).

Your brain, thinking this line is continuous (and thus likely the same color throughout) adjusts the colors in different areas to make the line continuous. So it seems more like a pattern-finding issue in the brain (which is really what most optical illusions take advantage of).

I want to see this same image with actually continuous, solid-color lines there. I have a sneaking suspicion the illusion would disappear.