In article <45afb6f1@news.povray.org>, war### [at] tagpovrayorg says...
> Daniel Nilsson <pov### [at] daniel-nilssoncom> wrote:
> > I'm sure there are comments to images in p.b.i of the type "It looks 
> > very dark" or "The colors are a bit washed out", even though it looks
 
> > good on the authors computer.
> 
>   If there were people seeing images like that, then they would see
> *all* images eg. on the internet like that. I think they would rather
> quickly tune the brightness and contrast of their monitors.
>
>   It's not as if all images in the internet have correct gamma info
> in them while povray images don't.
> 
No they wouldn't. They would only see the ones produced on systems with 
brighter or darker displays that way. Most, since most people are using 
basically the same hardware, don't play games, are not pros when it 
comes to graphics, etc, **never** adjust the brightness of the display, 
so unless the guy sending the image is on a Mac and you are viewing it 
on a PC, no difference is seen at all. Even if this does happen, most 
people chalk it up to the image "looking as intended", even if it isn't, 
they just don't know any different. Its only when two people with 
different systems actually compare notes that it becomes obvious that 
the PC made image or Mac made one is bleached or too dark. If you don't 
know there is a problem, you won't notice the problem, and sadly, since 
most applications do Software gamma, instead of hardware correcting by 
increasing/decreasing the entire output to the display, you can actually 
get "corrected" images that look too dark of bleached, because the 
colors on them "can't" be corrected numerically. How do you make &FEFE60 
"brighter" without making it almost white, or &101000 darker, without 
making it almost black? You can't. You can "hardware correct" the entire 
display to make "everything" brightened or darker, without altering the 
actually values in the image.

Frankly, other than the existing issues, I think there is a more serious 
problem with Gamma. Mainly, to work right you would need a graphics card 
that supported "more" colors than actually possible, in other words, use 
8 bits per channel for the "image", but have 10/12 bits per channel for 
the "card". That way the "image" would reside in the "middle range", but 
color values on the card might range from -15 to 270 per channel 
(forgive me if I did the math wrong). That way, if you need to gamma 
correct you *shift* the values of the image, not the entire display. I 
am 99.9% sure that it doesn't work that way, so you either end up 
adjusting the "values" in the image, which won't work if they are too 
close to the white or black thresholds, *or* you adjust the entire 
display to compensate, which then messes up any windows you are "not" 
viewing the image in.

Anyway, point is, with most formats, unless someone specifically tells 
you that they made the image on a system with a different gamma than 
yours, you a) probably won't know its looks wrong anyway, and b) in many 
cases they intentionally avoid making scene with obviously bright areas 
or obviously dark ones, where detail "will" be lost on a system that has 
the wrong gamma. This however isn't always either practical or possible. 
But I have definitely seen images in lots of place that you can't see 
well without making them brighter, especially on 3D sites.

-- 
void main () {

    call functional_code()
  else
    call crash_windows();
}

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