POV-Ray : Newsgroups : povray.binaries.images : yet another gamma test (discussed at p.b-t.) [~55KB] : yet another gamma test (discussed at p.b-t.) [~55KB] Server Time
17 Aug 2024 14:19:46 EDT (-0400)
  yet another gamma test (discussed at p.b-t.) [~55KB]  
From: Bob H 
Date: 25 Sep 2001 05:23:52
Message: <3bb04d28@news.povray.org>
To try and explain here, I wanted to ask everyone whether they understand
and have correct settings for their systems.  Attached is 4 renders, each
with different display and assumed gammas.

Of course, gamma info contained in the files, is lost on this because I put
all into a new jpg but it shows the lightness or darkness variation between
each.  I could post the originals too if anyone wants to check on gamma info
of the images themselves.

Anyway, what I had always previously done is to set Display_Gamma= in
Povray.ini according to appearance of the gamma test graphic found in the
doc.
Using 2.3 here most recently, and in the past 2.1 etc., with assumed_gamma
of the scene file set to the same or close to it I had thought the statement
in the doc about using assumed_gamma 1.0 was not right for me (others have
said so too).
When both are set to 1.0 it's once again fine though, of course.  Just makes
sense.  What I hadn't gathered about this before was the association of the
two different settings.  To me the doc reads as being 'set your display
gamma using the test' then 'use assumed gamma 1.0 for all new scenes'.  That
just couldn't be correct in my opinion.

So please have a look for yourselves if you would, and the main question I'm
leading up to is whether using 1.0 all around is right, or not?

BTW, upper right image is what I always got when trying to comply with the
doc before.  Lower right image is what some people might be doing.  Either
is wrong IMHO and only equal values makes sense, which is why the doc
reading confuses me on this point.

Bob H.
--
http://webpages.charter.net/omniverse/omniverse.htm


Post a reply to this message


Attachments:
Download 'display_assumed_gamma.jpg' (42 KB)

Preview of image 'display_assumed_gamma.jpg'
display_assumed_gamma.jpg


 

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.