"Kenneth" <kdw### [at] gmailcom> wrote:
>
> My *current* belief is that the reason has to do with the 'srgb' gamma itself,
> as opposed to gamma 2.2.
[snip]
>
> I *think* that POV-ray version 3.6 and earlier did not make use of 'srgb' as a
> gamma in any way, but rather 1.0 or 2.2, depending on the "user's preference"...

Sorry, I probably didn't make my point very clear.

n POV-ray versions prior to 3.7(?), and using an assumed_gamma of 1.0 for a
scene back then, the colors in 'colors.inc' (being 'linear colors') didn't look
right when used as-is-- they had a washed-out appearance, due to the
assumed_gamma of 1.0. Changing assumed_gamma to 2.2 'corrected' those colors to
be what we (I?) might expect, or so it appeared. (but disregarding the other
'internal' computational problems that this probably caused vis a vis using a
suggested assumed_gamma of 1.0)

Jump forward to v3.7xx and 3.8, with its 'proper' use of assumed_gamma 1.0 and
the introduction of the srgb color keyword for using 'gamma-corrected' color
values that do not look washed out-- for example, using srgb to change a
'linear' rgb color in colors.inc.

SO... using assumed_gamma of 2.2 in earlier POV-ray versions along with linear
color values there, but then in later versions using assumed_gamma 1.0 and with
srgb-corrected colors, the respective gamma appearance (and value) of a
particular color might be slightly off when the two schemes are compared-- due
to the slight difference in gamma-bending between srgb and 'straight' 2.2


Or so my reasoning goes ;-)

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