POV-Ray : Newsgroups : povray.tools.poser : Poseray: #version and and file gamma : Poseray: #version and and file gamma Server Time
30 Mar 2023 19:55:42 EDT (-0400)
  Poseray: #version and and file gamma  
From: clipka
Date: 19 Sep 2014 10:10:34
Message: <541c395a$1@news.povray.org>
Having recently updated to a new version of PoseRay (v3.13.23.587 to be 
precise), I noticed two things that I suggest to change:

(1) PoseRay does not write a "#version" statement in the scene file. As 
of POV-Ray 3.7.0, this statement is now mandatory (ideally it should 
even be the very first non-comment statement) - if such statement is 
missing, the scene is presumed to be a legacy (v3.6) scene, and certain 
features (most notably gamma handling) will operate in a compatibility 
mode. (You'll also get a waning message.)

The other is directly related to this:

(2) PoseRay writes image_map statements with a "gamma srgb" and bump_map 
statements with a "gamma 1.0"; both would be redundant if the scene 
specified "#version 3.7", and it is actually recommended to /not/ use 
these statements unless working with image files that are known to cause 
problems with POV-Ray's automatic image gamma handling. (And while I 
haven't tested it, using "gamma srgb" with high dynamic range images by 
default would actually be outright wrong, because these file formats 
default to a gamma of 1.0.)

Speaking of gamma and version, it might be helpful for users of POV-Ray 
3.6 if PoseRay would provide an option (which I'd suggest to be on by 
default) to automatically convert any non-HDR image files from sRGB (or 
whatever gamma they have according to in-file information) to a gamma of 
1.0. (Care should be taken though to prevent colour banding; dithering 
should probably solve that.)

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