clipka <ano### [at] anonymousorg> wrote:
>  From what I can see in the PNG header, you're using pretty
> unconventional gamma settings. For starters, File_Gamma=1.0 is generally
> not a good idea as it leads to the Windows Explorer thumbnail preview
> appearing differently. And as a matter of fact it's usually the
> thumbnail preview that lies to you, unless you have an exceptionally
> uncommon display gamma.
>
> My guess is that you're using File_Gamma=1.0 and Display_Gamma=1.0,
> while actually having a display with a gamma of around 2.2.
>
> The Display_Gamma=1.0 will make the image look the same in 3.7 beta
> preview render as if you had used assumed_gamma 2.2 in 3.6 with
> Display_Gamma=2.2, while the File_Gamma=1.0 will not have any visible
> effect on PNG files (except for viewers that ignore gAMA chunks, such as
> Windows Explorer's thumbnail generator) - it will just make the output
> more susceptible to banding artifacts.
>
> While it /may/ be that you adjusted your display for a gamma of 1.0, it
> is both uncommon (typical values are around 2.2, give or take) /and/
> will make virtually all of your software display nonsense unless you
> also informed Windows of the fact (or each piece of software separately,
> but only few pieces of SW provide a means to tell them about your
> display gamma).
>
> Whatever you're doing there regarding gamma, you're probably doing
> /something/ fundamentally flawed.
>
> And it's likely that you have a different taste than me: I do prefer the
> washed-out version, especially for a wallpaper.

I'm sure I am doing something wrong. In order to get everything looking good on
my monitor (CRT), I set the video card gamma to +1.0. If I set it lower or
higher I CANNOT get things to look right by adjusting the brightness and
contrast settings. If I set my video card to gamma 2.2 it looks absolutely
terrible.

You are right, I'm using POVRAY.INI settings "file_gamma=1.0" and
"display_gamma=1.0." I added "assumed_gamma 1.0" to the scene file. Everything
looks great on my computer (render preview and finished images displayed with
any program other than Internet Exporer) but .png images look washed out when
displayed in Internet Explorer. Between the video card settings, POVRAY.INI
settings, assumed_gamma setting, and monitor brightness settings something must
be wrong. (I don't think Windows XP has any gamma settings other than what the
video card driver adds.) But after lots of experimentation, the only thing that
doesn't work for me is the display of .png files with Internet Explorer so if I
convert to .jpg before posting everything will be fine.

By the way, even when I turn the file_gamma way down the image still appears
washed out in IE. I suspect there's something wrong with the way IE version 7
handles gamma. (At least it's different from all the other display programs I
use.)

Thanks for the tips!

Regards,
Dave Blandston

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