clipka <ano### [at] anonymousorg> wrote:

>
> #version 3.7;
> global_settings { assumed_gamma 2.2 }
>
> ....
>
> light_source { <-3000,3000,-3000> color rgb 1.2 }
>

Hello all! I finally have a new computer (well, a used one, with Windows 7
Ultimate, and a dual-core processor. No more Windows XP, sadly-- that one died.)
I've been away from the newsgroups for several months...

But I digress...

I decided to run your test scene with assumed_gamma 1.0 instead of 2.2, and
noticed something about your use of 'rgb' in the light_source. I changed it to
srgb (which I've started doing in all my v3.7xx scenes, to be 'color-consistent'
with all the other srgb colors I use), and noticed that the scene gets
*brighter.* It's an interesting (and unexpected) effect-- unexpected because,
when substituting srgb colors for rgb (under assumed_gamma 1.0), it usually
causes the lighting/colors to be be somewhat *darker* (as expected, due to the
gamma shift of the color components away from linear.) But in this case, the
result is the opposite-- it's brighter!

I assume this is because the light's intensity is greater than 1.0; but I don't
quite understand why. Is it a natural consequence of the srgb 'gamma curve',
affecting color components above 1.0? (Or maybe above a particular
'intermediate' value between 0.0 and 1.0?)

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