Linux gamma

[nc5p]

There was another thread here about Windows and Mac gammas being different. What about Linux? This Linux machine I'm on has The Gimp and Bibble, and they can produce good prints but they look grainy and contrasty on the screen. Any links for monitor calibration under Linux?

[Lee L]

Open a terminal and type: man xgamma

This will give you instructions on how to set the gamma.

I use: "xgamma -gamma 1.5"
to get one of my boxes with an older monitor on track.

You can also set gamma for r, g, and b separately as in:

"xgamma -rgamma 1.4 -ggamma 1.5 -bgamma 1.6"

I pull up a gray scale reference image and watch it as I run xgamma iteratively to get it looking its best.

You can also set the gamma in the monitor section of your xorg.conf file. Google for that. Another option is setting the gamma with xgamma in .bashrc or whatever shell you use.

I believe KDE has an GUI for setting gamma, I recall using kgamma a while back when trying out KDE, but I run Gnome, so haven't set KDE gamma in a long time. xgamma should work for any window manager running X.

Lee

[jd callow]

Lee,
This is great information.

[Lee L]

Forgot to mention... for fine tuning, xgamma appears use arguments for gamma of at least two decimal places, e.g. "xgamma -gamma 1.27". This allows very fine adjustments, and also works when specifying r, g, and b individually.

Glad you can use the info John. I like a system that works and allows you to tinker under the hood. With linux that requires some homework and some careful use of google, but I prefer it to the other options.

Also, with most shells in linux the up arrow will repeat the previous terminal command, so when iterating the xgamma command for fine tuning, just press the up arrow, use left and right arrows to work through the line to edit values, then hit return to execute the command.

Lee

[nc5p]

Thank you, Lee. I couldn't find the GUI for KDE but the command line works fine. Now my photos look "normal" on this machine.

[Lee L]

Thank you, Lee. I couldn't find the GUI for KDE but the command line works fine. Now my photos look "normal" on this machine.

Under Kubuntu 6.06 it's Kmenu | System Settings | Display then select the tab for Color & Gamma. Watch the color squares to make your adjustments. You have a choice of target gammas. 2.2 sRGB is one of them. There is an administrator mode that requires your password, but it doesn't say if that saves the values, or where. I'd have to look into that. A rough guess would be that adminstrator mode sets the system standard, and user mode allows preference settings for each user as they start X. I normally use gnome, but have a test box that allows the choice of Gnome, KDE, or XFCE. So I restarted X under KDE to check on the KDE GUI for gamma.

Lee