clipka <ano### [at] anonymousorg> wrote:
> Warp schrieb:
> >   Also POV-Ray 3.7 displaying the image on screen with one gamma setting
> > (with Display_Gamma is set) and writing the file with a completely different
> > gamma setting is a problem.

> It only is a problem if you set the Display_Gamma value wrong, or set 
> the File_Gamma value to a nonstandard value with a file format not 
> supporting embedded gamma information.

  It is a problem when POV-Ray ignores the File_Gamma setting, as seems to
be currently the case.

  Anyways, I don't really understand the reason to have a different gamma
setting for displaying the preview image on screen and another for writing
the image data to a file. If you specify different values, you will not get
what you see, but something different.

> >   Btw, a Display_Gamma of 1.0 produces (on screen) an image which is
> > basically identical to what POV-Ray 3.6 produces, all image_maps look
> > correct, etc. Is there a reason why it cannot be the default?

> Yes, there is: It's perfectly wrong for most systems.

  Then every single program out there which displays image is wrong, and
POV-Ray is the only program which is right?

  If I take a jpeg image and view it with Firefox, ImageMagick, The Gimp,
Konqueror or basically any software in existence which is able to read and
display jpeg images, they will all show the image in the same way. However,
if I use that same jpeg image as an image_map in POV-Ray 3.7 beta, using
default settings, eliminate all lighting effects and render an image like
that, the gamma setting for that jpeg image will be completely wrong: It
looks way too light and washed out. And not just a little, but quite
significantly. Basically the image is useless that way.

  However, when I tell POV-Ray to use a Display_Gamma of 1.0, then it will
start showing the image in the exact same way as all the other programs.

  If a Display_Gamma (and, I assume, File_Gamma when it's fixed) of 1.0
is not the proper way of fixing this problem, then please tell me what is.
Because as it is now, the default setting makes image_maps completely
unusable.

  If you don't believe me, I can show you examples.

-- 
                                                          - Warp

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