Ive <ive### [at] lilysoftorg> wrote:
>
> Well, now I have read through the whole thread. What a mess. There are
> so many false statements, combined with completely correct statements
> and - as usually - the worst ones: almost true statements.
> And then are the things that are simply not relevant anymore (like the
> whole discussion with Warp - Clipka expanded the color_map syntax so
> that none of the complains is still valid).

"Science advances by taking two steps forward and one step back."
Or here, maybe it was 1 step forward and two steps back :-P

I sometimes think of the newsgroups as a kind of 'community sketch pad, where
someone starts out by drawing a few basic shapes or blobs (the "idea"), then
others start adding their own doodles, then erasures, then recapitulations of
the 'history of art', then more doodles... until, hopefully at the end, there is
a 'nice final picture' of the original idea. But sometimes its a real mess
getting there, I agree. (And I'm certainly to blame, here.) But the final result
can be... awesome! Too bad that we can't clean up the mess, by deleting all the
extraneous stuff and dead ends. ;-) Ah, but that's the interesting (and messy)
history of how we got to the end result... to be kept in the archives for all
time, ha. :-O
>
> My point of view here is quite simple: If you aim at any degree for
> realism in your renders you'll have to use assumed_gamma 1.0 and make
> sure that everything that follows the expression rgb is encoded with a
> linear gamma.

I'm genuinely curious about image_map use in that context, and how it is handled
by POV-ray internally. You mentioned, I think, that the *linear* contents of the
image's colors/brightness are used for internal computations(?), regardless of
what we 'see' in the render. If I'm correct about that, do you know if radiosity
from an image_map uses the *linear* values to 'shed its light' into the scene?
In other words, are the radiosity patches' 'colors' based on the linear-color
values of the image? Or does radiosity 'radiate' the 2.2-gamma colors, the image
colors that we 'see' in the render? It would seem that there would be a wide
color difference between the two schemes... with perhaps different visual
results than we might imagine or expect, depending on the scheme used. (A rough
analogy would be, using rgb colors vs. srgb colors for an object's pigment.)

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