Warp wrote:
>   Gamma information exists in OSes so that images will look approximately
> the same as in other systems. However, this is an issue if image viewer
> programs (and to some extent image editors). In other words, an image
> viewer gets an image with "raw" pixels, and then it gamma-corrects them
> to look good on the specific platform. In other words, this correction
> is a duty of the viewer program (or the OS itself).

Yes, exactly! And if you refer back to the original post you will see
exactly that problem taking place - POV-Ray is a viewer of images! It shows
you the preview, and the original poster complained that his viewer program
does not handle gamma correctly. POV-Ray as viewer does. Now it writes the
image correctly, with the information needed to recreate exactly its
preview. But the outside viewer program ignores what POV-Ray included in the
image.

>   In the past (at least with pov3.5) people have abused povray's gamma
> correction for something completely different than what it was really
> intended for: They have used it as a kind of post-process filter to
> alter the brightness of the resulting image.

Yes, because one could manipulate "gamma" from within the scene. This was
the actual flaw. Gamma is something you set *once* for your system and then
forget about. Assuming all programs you use support it, everything will be
fine. That is why in 3.7 gamma changing from within the scene is deprecated,
and will be no longer possible in whatever release comes after it. Setting
in once in povray.ini/.rc will do.

	Thorsten

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