The Gimp and HDR

It seems that there are lots of people that don't understand that The Gimp is not capable of doing HDR images. There is a simple reason for this, which involves the way The Gimp represents image files. Without being too technical, I'll try to explain.

The Gimp's basic model represents each pixel as 3 different numbers between 0 and 255. This means that it can represent only 16581375 different colors per pixel. I say only, because, if you were to use 3 floating point numbers, from 0 to 1, or 3 numbers from 0 to 65535, or some other power of 2 (minus 1), you then are able to represent many more colors; you become able to represent a higher dynamic range of colors.

Even if The Gimp supported more pixel values, our monitors can't, and we need to use a process like tone mapping to convert the computed HDR image (comprised of some combination of multiple exposures), back into something viewable; something where the range of pixels is made up of 3 integers from 0 to 255 (in the general case).

This doesn't mean The Gimp sucks, because it certainly doesn't; it just means that it has some limitations and one has to be mindful of them. This "problem" of image representation is only really visible if you're looking for ultra-high quality output, like movie producers, and most photo professionals. Amateurs need not worry.