Will W wrote:
> 
> [...]
> 
> It went into history. Although neither you nor your friend have updated your
> hardware in quite a while, you are both staying current with software and
> recent trends. So naturally you sent her the image in a lossless compression
> .png file, which is so much better than the lossy old jpg files everybody
> used to use. The png file also carries the gamma information so it can tell
> whatever machine it ends up on how to best display itself. No problems.

Except the 'small' problem of very low quality results.  Applying gamma
correction to a 8 bit image will lead to immense quality losses (and the
known effects like color stripes in the skies etc.).  

This whole discussion is not any different than a lot of other ones that
have been made before in these groups.  There are always the same two
points:

a) what gamma settings one should one use in ini and scene file?
b) how one does achieve the image looking right on all computers?

Both questions have a technically satisfying answer:

a) adjust display_gamma according to the characteristic of your output
device, use 'assumed_gamma 1' if you want POV-Ray to adjust gamma for you,
don't use any assumed_gamma if you don't.
b) render the image with linear colors (no assumed_gamma) to 16bit output
and apply gamma correction individually on the system where the image is
displayed.

This solution of course has its practical problems:

- people who are used to graphics programs which don't apply a gamma
correction afterwards (like most paint programs) are not used to defining
colors in this way - they will intuitively use wrong colors.
- most image displaying programs are neither able to deal with more than 8
bit color depth nor to automatically apply the appropriate gamma
correction before showing the images.
- 16 bit images tend to be somewhat larger.

And i guess this situation will be the same in 2005 except one can hope
that the abilities of image display programs are somewhat better by
then...

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 28 Feb. 2003 _____./\/^>_*_<^\/\.______

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