In article <437420f7$1@news.povray.org>, tek### [at] evilsuperbraincom says...
> You'll see exactly the same thing if you take a photo of an orange, then 
> load it into your favourite paint program and gamma correct it.
> 
> Gamma effectively adjusts the brightness of the midtones and leaves 0 and 1 
> in the same place, so if your orange colour is <1,0.5,0> then with 
> assumed_gamma it will look more like <1,.73,0>, which is 
> <1,pow(0.5,1/2.2),0> because your monitor gamma is probably 2.2ish.
> 
> If you want to pick a colour in a paint program and have it look the same in 
> pov then you need to gamma correct it from your monitor's gamma space (the 
> space you picked it in) into the assumed_gamma space you've told pov to work 
> in. Usually that means applying pow(<colour>, 2.2) to it.
> 
> Personally I find it's just easier to always work with assumed_gamma 1 
> turned on, and pick numbers in pov that look right, and forget about gamma 
> space altogether.
> 
The assumption, (or at least how I assume its supposed to work), is that 
they set your assumed gamma to what your display actually is, so that if 
someone looks at it on one with a 1.0, it looks the same as on a 2.2, or 
the same on a 2.2 as it did on your 1.0 display, etc. What people are 
screwing up is that they are setting the gamma to something that has 
*nothing* to do with their displays actual gamma, so when they load it 
one something else, it looks wrong. In the case of programs that 
correctly handle the setting in the file, *they* are assuming the 'real' 
gamma is different that your monitor and are dropping or increasing the 
image colors to 'match' what they 'think' your display uses, which is by 
default 1.0, not 2.2. In other words, those programs are doing exactly 
what they are told and compensating for *their* assumed gamma of 1.0, by 
shifting everything to 2.2, when in fact the display is the same one as 
used to produce the image, so 'should' have the same 'real' gamma.

Basically, if you use the damn thing wrong, its your own fault when it 
doesn't work, which is imho a real good reason to leave it at 1.0, then 
let those application, if they are set up correctly, adjust things to the 
gamma or the display, not the other way around. Its like manufacturing 
something that uses AA batteries, then 'suggesting' in the manual that 
they try to cram a 9V battery into it. Of course its going to go wrong.

-- 
void main () {

    call functional_code()
  else
    call crash_windows();
}

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