"Stephen Klebs" <skl### [at] gmailcom> wrote:
> /*
> Gamma - 3.6/3.7 Beta
>
> This is an example of my problems with gamma in 3.7.

Like you, I have grown comfortable with, and accustomed to, the 'look' of the
pre-3.7 gamma set-up (i.e., using assumed_gamma 2.2 rather than 1.0). Which in
itself was *wrong* according to the old docs; they used to say that
assumed_gamma should be 1.0, not 2.2. (While at the same time implying that
assumed_gamma should be the same as display_gamma--which would be 2.2, not 1.0)
It was all kind of screwy, IMO. But the main reason *I* have used assumed_gamma
2.2 forever, was probably the same as you--that it matched my Photoshop (and
many other apps') representation of a similar 0-100% grayscale chart. Not to
mention digital camera photos, web browsers (reproducing jpeg photos), etc. I
could never get used to the look of using assumed_gamma 1.0 in POV-Ray.

This gamma change in v3.7 is probably the biggest change to impact POV-Ray in
quite some time. Yet I *do* see the reasoning behind the new changes, I guess
the main one being that POV-Ray needs to operate on 'gamma-uncorrected' values,
in order to do accurate light-based calculations. (And it corrects some internal
inconsistencies, I believe.) This gamma thing has been a thorny issue for years,
and I applaud Clipka and the other developers for even daring to tackle it, to
iron out the issues. The changes were bound to cause many of us to howl and
protest, because, AFAIU, it *does* mean we will have to go back to our many
legacy scenes and rework them (I think that includes assumed_gamma 2.2 AND 1.0
users, though I don't know for sure.) I'm personally not averse to doing
so--even though it *will* be quite a chore--because it will result in a more
coherent and accurate approach to lighting, colors, etc. And Clipka has
mentioned that a 'pre-3.7 gamma switch' is being discussed (which would seem to
be a solution to 'our problem'-- less of a 'blunt weapon' approach than simply
using the version 3.6 directive.)

What *does* bother me a bit about your 3.7 grayscale test is that it looks
identical (or very similar) to the results when using v3.6.1 and assumed_gamma
1.0.  :-(  Yet if 3.7 is doing what it's supposed to do--and I have no reason to
think otherwise--I guess I'm just going to have to get used to that ;-)

Ken

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