[gavanwoolery]

Square rooting the color is a trick I have used for ages, but I have not frequently seen it elsewhere. It will do pretty much the opposite of multiplying the color by itself - i.e. decrease the contrast and produce a "softer" color space still in the 0-1 range.

In general, you can produce a variety of interesting color-space transformations with simple math on the current fragment, as opposed to more complex methods that rely on sampling output, like HDR processing.

Here is a page on more advanced color space manipulation: http://filmicworlds.com/blog/linear-space-lighting-i-e-gamma...