many people are like HDR wow awesome cool blabla..
but most of em dont even really know what it is, so heres a little explaination:
upto now, colors have been measured in 3 numbers.. each number represents a color, red, green or blue, the number can go from 0(means this color is not included) to 255(means this color is included at its max)
so 0, 0, 0 would be black, and 255, 255, 255 would be pure white.
most of us know that much, but the thing is, in real life, light is infinite, it doesnt end at a maximum number like 255, so what HDR(high dynamic range) does, is the following:
it measures the amount of lighting in a number from 0 to infinite, but usually, 0 would be black, and 1 would be the full color IF the variable brightness shader isnt used(ill get back to this later)
numbers like 0,4843902309 are possible in this case, the problem is, the monitors we use are still based on the RGB system, so the colors will have to be translated back to the old RGB system, rendering the whole HDR thing useless.
thats where shaders come in, for example, the muchly used Bloom shader, it lets areas that lit up higher than HDR value 1 give a nice glow (see the unreal tournament pictures for that)
another thing that cant be missed to get profit out of HDR is the variable brightness shader. if your screen is filled with pure white, the brightness will keep going down until the level of brightness is normal again, this is handy for indoor/outdoor areas, because outdoor areas are usually much brighter than indoor, its just that our eyes get used to it rather rapidly.
hope i cleared up stuffs, youll notice that if you download HDR files (images but saved with HDR values) and get a HDR program to open it, the colors wont be like [120, 220,100] but prolly like [0,389-0,378-0,978]