This page was created in order to test whether browsers implement color correction or not. Modelled after a similar test for MNG images by Gerard Juyn, the concept is quite simple: if all three of the images in each row look the same, the browser passes. If they're all different, it fails.
Specifically, the pixel data in two of the three copies of the image were modified. The left image has had its red and green channels swapped, while the right image has had its red and blue channels swapped. (The center image is the original, of course.) In each case, the corresponding color-space chunks have been similarly modified to cancel out the color-swap, which is why the images will look the same on browsers that fully implement color correction according to the PNG specification.
The first row uses the (simple) PNG chromaticity chunk, cHRM:
The second row uses a full (though fairly basic) ICC profile embedded in the PNG iCCP chunk:
Both rows should look approximately like this, if the browser does color correction properly:
If the rows instead look like this, the browser does not support color correction:
Note: the six individual test images (and, separately, the three embedded
ICC profiles) are licensed under the
Creative Commons Attribution-NonCommercial 2.5 License.
Copyright © 2005-2009 Greg Roelofs.