Monitor Calibration with Dual Screens

imarriedyoung · 07-11-2014, 02:41 AM

I recently came into possession of a neat little 1680x1050 resolution monitor. My days of dreaming for a dual monitor were over...or so I thought. I've gotten everything to work both with x11 parameters inside of xorg.conf.d and also with xrandr initially (that is, I've switched over from xrandr to the X11 config, but may switch back, in either case they both do the same thing.);

So it works, but this little sucker isn't necessarily a spring chicken, so it's color correction is off. I've worked in imagery for a long time, so I'm fortunate enough to own a monitor calibrator, and I found a nice lightweight tool called xcalib that'll let you load previously generated .icm or .icc color profiles.

The problem is, I can't seem to figure out how to specify to xcalib which monitor to load the settings to. I don't even know if this is possible. Having two X sessions seems crazy, and trying to add extra "screen" parameters and monitor parameters in xorg.conf.d isn't really differentiating things.

More accurately my question is, in the tl;dr sense of things: Does anyone know if I can specify two separate "screen's" (or "displays", whatever you want to call them) inside of X that I can, later, individually have xcalib apply calibrations to?

At the moment, when I issue an xcalib command such as:

Code:

xcalib -d :0 /usr/share/local/color/icc/some_color_profile.icm

It seems to, strangely enough, apply solely to my new, smaller, monitor, and not to my other monitor. But I've also learned that looks can be deceiving and I don't know if it's applying it to everything on both screens.

55020 · 07-11-2014, 04:43 AM

I don't know whether this will actually work (depending on how your screens are configured), but have you tried ':0.1'? i.e.

Code:

xcalib -d :0.1 /usr/share/local/color/icc/some_color_profile.icm

This may not work if you are using the nvidia binary driver (or that information may be out of date)

In the brave new world of Linux desktops this can be controlled by colord, but afaik the only colord-enabled desktop for Slackware at the moment is Cinnamon.

imarriedyoung · 07-11-2014, 05:51 AM

Damn, no, that doesn't work, although I got excited when I saw that suggested elsewhere: "Error - Can't open dislpay :0.1". Thanks though! It might be a moot point all and all, but I'm curious of anyone has some kind of resolve. I have heard some luck with argyllcm and its tool. In an ideal world you could slip ICC profiles directly into the monitor, like firmware updates; may sound crazy but a man can dream, can't he?

business_kid · 07-11-2014, 06:30 AM

A couple of things.

Man xorg.conf is your friend, but I believe 'left' and 'right' are the usual things to specify. It may also be possible to do ''top' and 'bottom' simply as options in the monitor description

Quote:

SebSection Monitor
<blah>
Option "Left"
<blah>

You say it's old. If the tube is a 'delta gunned' job (Red, green & blue cathodes in a triangle) it's probably better to adjust the monitor as they are incorrigibly awkward and changeable. There might be pots or coils inside.

The usual thing now is the three 'guns' in a line inside the glass. Convergance is easy on those (

Often these problems can be fixed by degaussing the screen. A big heavy coil passing loads of AC (I usually used a transformer) is brought close to and round the edge of the picture and should pull it out of shape. Then get it far away before you switch off to avoid a spike remagnetising it!

imarriedyoung · 07-11-2014, 06:39 AM

Well I say old but it's still a simple and rather digitally interface-able flat screen LG so no need for degaussing or anything crazy. I have set that up under a working xorg.conf.d conf file but how would I specify to xcalib to load to the "left of" monitor /screen and the "right of" one? I'll post the contents of my xorg.conf tomorrow morning.

business_kid · 07-11-2014, 02:16 PM

Quote:

Originally Posted by imarriedyoung

Well I say old but it's still a simple and rather digitally interface-able flat screen LG so no need for degaussing or anything crazy.

I am glad to hear it.

Quote:

Originally Posted by imarriedyoung

I have set that up under a working xorg.conf.d conf file but how would I specify to xcalib to load to the "left of" monitor /screen and the "right of" one? I'll post the contents of my xorg.conf tomorrow morning.

Left and right are specified in xorg.conf.d in the monitor sections. I would keep xorg.conf to a basic original and put the work in xorg.conf.d - otherwise you'll have the same things configured in two places and potentially confuse yourself

imarriedyoung · 07-11-2014, 07:07 PM

Output of "cat /etc/X11/xorg.conf.d/10-monitor.conf"

Code:

[Sat Jul 12, 09:16 AM | ~]
>> cat /etc/X11/xorg.conf.d/10-monitor.conf
Section "Monitor"
    Identifier   "HDMI-1"
    Option  "PreferredMode"  "1920x1080"
    Option  "LeftOf" "DVI-I-1"
EndSection

Section "Monitor"
    Identifier   "DVI-I-1"
    Option  "PreferredMode"  "1680x1050"
    Option  "RightOf" "HDMI-1"
    Option  "Position" "1920 0"
EndSection

Section "Screen"
    Identifier "Left Screen"
    SubSection "Display"
        Virtual   1920 1080
    EndSubSection
EndSection

Section "Screen"
    Identifier "Right Screen"
    Monitor "DVI-I-1"
    SubSection "Display"
        Virtual 1680 1050
    EndSubSection
EndSection

Section "ServerLayout"
    Identifier "Main"
    Screen 0 "Left Screen"
    Screen 1 "Right Screen"
EndSection

My ServerLayout section is a total guess stolen from someone else's conf. The two screens work and output correctly, whether I do it via xrandr or xorg.conf.d, but what I'm trying to figure out is how one would tell xcalib (or some similar tool I can get to run on slackware) to apply an icc profile specifically to the 1920x1080 on the left, and another to the 1680x1050 to the right.