POV-Ray : Newsgroups : povray.binaries.images : I think warp is right ... 3.7 gamma : Re: I think warp is right ... 3.7 gamma Server Time
4 Nov 2024 14:59:58 EST (-0500)
  Re: I think warp is right ... 3.7 gamma  
From: scott
Date: 2 Sep 2009 04:26:52
Message: <4a9e2c4c$1@news.povray.org>
> Guys, you're still on the wrong track!
>
> As I've pointed out to Warp about half a dozen of times, it is the /input 
> file/ gamma handling that's broken indeed.
>
> Your image looks washed out because the texture /is/ washed out (from the 
> render engine's point of view).

Exactly.  POV assumes all input files and colour literals are in linear 
colour space.  Images and colours that you see on your monitor (eg in 
picture viewer, colour picker, or on the web) are not in linear colour 
space, they have already been gamma corrected.  Unless you "undo" the gamma 
correction before handing them to POV, your output file is going to look 
very washed out as essentially they have been gamma corrected twice.  This 
is very obvious if you pick colours in Windows and then try to use them in 
POV, without undoing the gamma correction first they can be very obviously 
wrong!

> Convert the texture file to PNG using IC for instance (to make sure it has 
> a gAMA chunk, too), and you should be perfectly fine.

Or alternatively you can use a paint program to undo the gamma correction 
and save as bmp or jpeg.  I think someone also posted some SDL code here to 
do the conversion within POV.


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