In article <45bc6ebb$1@news.povray.org>, nicolas$george@salle-s.org 
says...
> Patrick Elliott  wrote in message
> <MPG.20243ea770f89bec989fd8@news.povray.org>:
> > Sigh.. How about "blending" or "blurring" then, since the problem is 
> > that, basically, if you have a fine gradient that you "need" to have 
> > stay that way for the detail to be obvious, its going to screw things
 
> > up. You lose data "period". It doesn't matter if it "technically" isn't
 
> > messing up the white or black points, if it never the less has the 
> > unfortunate side effect of making it "look" like its doing so, by losin
g 
> > colors that *should* remain the same, just brighter or darker. Its what
 
> > the perception is, not what may or may not actually be happening. And i
n 
> > 90% of cases, people attempt to use Gamma to correct for how "bright"
 
> > the image is, not if green looks 0.01% more blue on Fred's display than
 
> > on Ralph's.
> 
> Well, with discrete bounded color values, it is not possible to losslessl
y
> increase the brightness. It is the pigeonhole principle.
> 
> Now, not being able to see the dark areas because there is not enough
> contrast is a loss too. So the question is not loss / no loss, but betwee
n
> different forms of loss. It is a matter of compromise. And under the
> circumstances, a light gamma correction is a very good compromise.
> 
Not if the quality of the image is "dependent" on those fine details, 
then its a bad compromise, since the hardware can't adjust "some" areas, 
instead of all of them, nor can software do it at all, since its 
constrained to those limited color ranges. The only workable solution 
would be if someone came up with a 64-bit color range, then set normal 
white and normal black at some higher number than 0. In other words, 
increase the color space, so that you can adjust it in a range that 
allows for changes due to both the color variations "and" the brightness 
differences that some systems have. The issue between MAC and PC with 
some games and images is not that the colors themselves "look" wrong, 
its that the entire spectrum is "darker" on most PCs than it is on a 
MAC. Adjusting the brightness of the display fixes this, usually, but 
can have unintended consequences to the colors. Gamma.. Tries to correct 
the ranges, but loses the fine detail you couldn't see in the first 
place, just on the opposite end from what ever you are adjusting from. 
Two dark means fine high end detail gets the most screwed, too bright 
and you lose detail in the dark areas. In cases where the problem is 
already not being "able" to see those areas, you need some way to adjust 
the "entire" image, not approximate it. Currently, cards don't seem to 
be able to do something like:

Gamma_Region(100,100,500,400,1.0)

Just:

Gamma_Everything(1.0)

This means if you don't want the "correct" hardware method, or you don't 
have it, you end up with an approximation, which can turn out to be 
*far* worse than just leaving it the way it is, in some cases.

-- 
void main () {

    call functional_code()
  else
    call crash_windows();
}

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