Gamma on Linux
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Hi all,
I'm trying to understand the gamma tuning of Linux: I always read on Internet that we aim at gamma 2.2, but if I set Gamma 2.2 through xgamma, I get a way too bright monitor, I cannot even see black. The best value (without real calibration) is 1.0 (xgamma -gamma 1.0). I'm a bit puzzled by this: what is the nominal gamma of my monitor (a Samsung SyncMaster, so a very common one)? If it is 2.2 why shall I set it to 1.0? Any help or suggestion? Thanks in advance Leonardo _______________________________________________ Digikam-users mailing list [hidden email] https://mail.kde.org/mailman/listinfo/digikam-users |
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You wan't to correct the signal in order to make the display be 2.2. Read: http://www.linux.com/archive/feature/113936
2010/2/3 Leonardo Giordani <[hidden email]> Hi all, _______________________________________________ Digikam-users mailing list [hidden email] https://mail.kde.org/mailman/listinfo/digikam-users |
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In reply to this post by Leonardo Giordani-2
Leonardo Giordani píše v St 03. 02. 2010 v 16:22 +0100:
> Hi all, > > I'm trying to understand the gamma tuning of Linux: I always read on > Internet that we aim at gamma 2.2, but if I set Gamma 2.2 through > xgamma, I get a way too bright monitor, I cannot even see black. The > best value (without real calibration) is 1.0 (xgamma -gamma 1.0). Your monitor has definitely native gamma around 2.4 - 2.5. Higher native gamma results in darker mid-tones. xgamma (or setting in /etc/X11/xorg.conf or the video driver tools like nvidia-settings panel) tells X server to change the gamma of video card LUT (look-up-table). Adjustments bigger then 1 make the mid-tones lighter. Additionally, there are tools (xcalib, dispwin) which can do finer adjustments to the video card LUT then just the simple xgamma. However, one needs to use a calibration device. What you finally see on your screen is a result of monitor's native gamma and any gamma adjustments to video card LUT. (Monitor gamma divided by LUT gamma.) > I'm a bit puzzled by this: what is the nominal gamma of my monitor (a > Samsung SyncMaster, so a very common one)? If it is 2.2 why shall I > set it to 1.0? The various tools for gamma adjustments do not tell you what is the visual gamma, but only what gamma adjustment is done to LUT. regards, Milan Knizek knizek (dot) confy (at) volny (dot) cz http://www.milan-knizek.net - About linux and photography (Czech language only) _______________________________________________ Digikam-users mailing list [hidden email] https://mail.kde.org/mailman/listinfo/digikam-users |
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Thank you, now the whole thing is clear :)
2010/2/3 Milan Knížek <[hidden email]>: > Leonardo Giordani píše v St 03. 02. 2010 v 16:22 +0100: >> Hi all, >> >> I'm trying to understand the gamma tuning of Linux: I always read on >> Internet that we aim at gamma 2.2, but if I set Gamma 2.2 through >> xgamma, I get a way too bright monitor, I cannot even see black. The >> best value (without real calibration) is 1.0 (xgamma -gamma 1.0). > > Your monitor has definitely native gamma around 2.4 - 2.5. Higher native > gamma results in darker mid-tones. > > xgamma (or setting in /etc/X11/xorg.conf or the video driver tools like > nvidia-settings panel) tells X server to change the gamma of video card > LUT (look-up-table). Adjustments bigger then 1 make the mid-tones > lighter. > > Additionally, there are tools (xcalib, dispwin) which can do finer > adjustments to the video card LUT then just the simple xgamma. However, > one needs to use a calibration device. > > What you finally see on your screen is a result of monitor's native > gamma and any gamma adjustments to video card LUT. (Monitor gamma > divided by LUT gamma.) > >> I'm a bit puzzled by this: what is the nominal gamma of my monitor (a >> Samsung SyncMaster, so a very common one)? If it is 2.2 why shall I >> set it to 1.0? > > The various tools for gamma adjustments do not tell you what is the > visual gamma, but only what gamma adjustment is done to LUT. > > regards, > > Milan Knizek > knizek (dot) confy (at) volny (dot) cz > http://www.milan-knizek.net - About linux and photography (Czech > language only) > > _______________________________________________ > Digikam-users mailing list > [hidden email] > https://mail.kde.org/mailman/listinfo/digikam-users > Digikam-users mailing list [hidden email] https://mail.kde.org/mailman/listinfo/digikam-users |
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