My JPEG images were only meant to illustrate the article. Anyone interested in making the comparison in Photoshop should use the original image on Akiyoshi Kitaoka’s site.

Edwin Land (the inventor of Polaroid) did some very interesting research on the perception of colours being dependent on the surrounding colours. He was able to predict what a colour patch would look like by running a photocell “mouse” across the nearby patches.

When an image contains less than 256 colours and needs to be sharp, it should be posted as a GIF, not a JPG. This applies to most colour illusions (and to maps, graphs, and diagrams). The JPG process can change colours as well as losing sharpness.

Thanks, Charley, for yet another one of your hundreds of fascinating and informative pieces. BTW, I’m a photographer working in Photoshop and other image editing programs, and I often encounter this kind of illusion in real world situations. I’ll have some subtle pastel that I want to intensify, say a rosy tinge in the sky perhaps, but when I try to increase the saturation, nothing happens. A check of the info palette then reveals that the color is actually neutral, or another shade of blue, damn. It just looks pink or peach because of the surround.

The discrepancy may simply be JPEG color shift (an unfortunate byproduct of JPEG compression), but yes the point is that they are not the widely different colors they appear to be.

Thanks. I’m glad you like the site.

RGB: 54-234-137 and in Munsell 4.3G 8.1/11.9

and the other is:

RGB: 3-253-170 and in Munsell 7.7G 8.6/11.9

What I think is important to realize is that these two colors have almost the exact same chroma and nearly the same value, but their hues aren’t the same. 4.3 and 7.7 is a big jump. I think, as you state in your post, color relationships are the hard thing for many people. But here we can see that you can do some interesting things by adjusting the hue and not the value or the chroma.

Great site by the way! :)