Gamma in PNG
Moderator: xnview
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Solovei95
- Posts: 16
- Joined: Tue Mar 29, 2011 11:14 am
Gamma in PNG
It does not work PNG gamma correction
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xnview
- Author of XnView
- Posts: 47222
- Joined: Mon Oct 13, 2003 7:31 am
- Location: France
Re: Gamma in PNG
You means that gamma in PNG are not used?Solovei95 wrote:It does not work PNG gamma correction
Pierre.
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Solovei95
- Posts: 16
- Joined: Tue Mar 29, 2011 11:14 am
Re: Gamma in PNG
XnView does not work native gamma correction in PNG.
The simplest formula is:
pow (channel/255, 1 / (gamma * 2.2));
gamma - gamma from PNG gAMA chunk
channel - RGB channel
The simplest formula is:
pow (channel/255, 1 / (gamma * 2.2));
gamma - gamma from PNG gAMA chunk
channel - RGB channel
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DOS386
- Posts: 291
- Joined: Sun Jun 11, 2006 2:43 pm
Re: Gamma in PNG
The preferred colorspace is sRGB anyway, not pow(unpredictable random value).Solovei95 wrote:XnView does not work native gamma correction in PNG.
http://libpng.org/pub/png/book/chapter1 ... ch10.div.6
http://libpng.org/pub/png/spec/1.2/PNG- ... tml#C.sRGB
http://en.wikipedia.org/wiki/SRGB
There is indeed no WinZIP under my rock.
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XnTriq
- Forum Librarian
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Re: Gamma in PNG
- Willem van Schaik: PngSuite » Gamma values
- Henri Sivonen: The Sad Story of PNG Gamma “Correction”
- Trevor Morris: The PNG Gamma Dilemma