GNOME Bugzilla – Bug 124170
gamma level must be corrected -- user settings
Last modified: 2010-09-29 17:08:09 UTC
Modern displays for almost every architecture are wrong. See bug 124072 for a description. The control center needs a "gamma correction level" setting in a "display" group that allows the user to change the display's gamma level. It should default to a sane value (somewhere around 1.7 for PCs) -AND- GNOME should set that at startup (but maybe that feature is in another product. I'm new to this bugzilla.)
Control center is right for both of those.
I second this. A proper Gamma control panel is needed, which sets xorg.conf too. Something like this GTK app http://www.pcbypaul.com/software/GAMMApage.html An excellent reference for gamma correction is here: http://www.normankoren.com/makingfineprints1A.html#gammachart Maybe you can even get permissioon to use his chart, it is arguably the best one there is. Both Windows and Macs have long had default Gamma settings, 1.8 for Macs (best for graphics/video/pre-press) and 2.2 for Windows (most of the rest). The sRGB standard as used by the W3C also uses 2.2 (it was devised by Microsoft and HP and is meant to represent the "average" (ie poor PC) monitor). My experiments on Linux has 2.2 as way too light, though. Historically it is understandable that Unix/Linux, being command-line based and used mainly for servers and non-graphical work, hasn't set a decent default gamma, but if Unix/Linux hopes to take on the Desktop market (which Gnome does), then a decent default Gamma must be set before it gets too popular, or the change will be more painful down the line.
XFCE is doing that in their control center, in the same screen used to set the resolution: http://shots.osdir.com/slideshows/slideshow.php?release=740&slide=24
I think a dedicated Gamma control panel something like the Adobe one for Windows (only better) would be preferable (else it would have to be on a separate tab), as simply having a Gamma slider doesn't help the user to know what to set it to. There needs to be helpful Tooltips and explanatory text, optionally a Wizard. I've found that an XGamma of 1.45 is the same as a Gamma Correction of 1.8 (I don't know why), so you can't simply go by some theoretical nubers, nor should you as you have to set your monitor first then adjust for your environment using test images.
CC:'ing Ross on gamma stuff
If you are going to handle gamma, you'll get bug reports about colour profile. I've been planning for a long time to add more to the screen resolution capplet, renaming it to just screen. A toggle between: * gamma (with a slider for people In The Know, and a wizzard to determine it) * colour temperature (ditto) Or: * colour profile (file selector to pick a ICC file) If you pick the first options a colour profile using libicc will be created. The profile would be set on the root window using my XICC specification (eog, kritta, and gimp all use it). The one downside of this is that colour correction is all-or-nothing, as the gamma isn't passed to xgamma but embedded in the profile (thus avoiding double-correction). I guess it would be possible to write a profile that assumes 1.0 gamma and use xgamma to set the ramp in the first case, but that doesn't help in the second. Basically we need a new X that use CIE instead of RGB, and then we can calibrate in the server. That, sadly, isn't likely.
Dupe of 124072?
I think these were for different components. Maybe now it's a dup.