> I guess that ALL not-too-old systems perform this correction. So,
according
> to me, I would rather agree with Tim, and POV scenes should be designed
for
> linear display and linear values in output files. This means, if I am not
> too wrong, that either both assumed_gamma and Display_Gamma should have
the
> same value (typically 2.2) or no "assumed_gamma" directive should be in
the
> code.

I think you misunderstood me, I don't think that Display_Gamma and
assumed_gamma should be the same, it's just that when they are the same, the
input images look like I expect them: no gamma correction applied.

I'm not too sure about how displays handle gamma, if they adjust the input
etc. I don't think mine does, but I've yet to read a little about this
mentioned "sRGB"...

What I've done in the past, because that's what POV-Ray's docs say, is to
set assumed_gamma to 1.0. Then, Display_Gamma 2.2 is used to adjust the
final image for the display (which has a gamma of 2.2 in my case, tested
with the image supplied in the docs as well). That's what's in the docs.
Of course, if your monitor "calibrates colors to linear space", you'd have
to set Display_Gamma to 1.0, not 2.2.

My macro simply applies the inverse gamma correction, so that after
POV-Ray's gamma correction, the image input looks like the output. To
achieve that, the gamma given to the macro has to be the same as
Display_Gamma and assumed_gamma should be 1.0. Of course the macro can be
used for other gamma-corrections as well.

(I'm actually thinking about doing some more stuff with functions and
images, to create some sort of simple compositing-script. I tend to be a
little geeky and nerdy about creating my animations/images with pure POV-Ray
(or at least, with some sort of script), cause I like to be sure that I can
reproduce it *exactly* at a later date. :-) )

Regards,
Tim

-- 
aka "Tim Nikias v2.0"
Homepage: <http://www.nolights.de>

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