Many people who have worked in the professional graphics department in either Mac or Windows have learned that a calibrated display is a valuble tool in creative design. Macs have a manual display calibrator built into OS X that is pretty darn good. It allows the users to adjust color balance in varying gray scale levels. To a trained eye this can nearly be as good a hardware calibration. ICC profiles can as well be created for printers, scanners… Creating an ICC profile will give very very accurate colors to be able to produce and reproduce across different monitors and medium.
Linux isn’t a powerhouse for desktop publishing. Alot of people still use older versions of Photoshop instead of GIMP (I suspect that’s it’s more for the plug-ins that anything else). And calibration in Linux is still in its infancy. So what can be done in Linux?
Keep in mind readers that I haven’t worked in desktop publishing in quite a while but this is what I found out I can do in Linux.
Lprof is a graphical (qt) application to create ICC profiles for camera, scanners and monitors.
I installed Lprof and I have Gnome so I thought that alot of qt applications may get pulled in but Portage only had to pull in one qt library so it wasn’t so bad.
With Lprof can set a generic color space, a white point(D65 – daylight, is the standard for most desktop LCD’s and monitors), and also a gamma. Lprof will need a screen 1024×768 to adjust the gamma, this can be got around for small displays by making the desktop scroll in the
SubSection "Display" Depth 16 Modes "800x600" "640x480" Virtual 1024 768
A more specific color space (RGB values) can be defined, but Lprof has no way manually test it.
Xcalib is an utility for setting an ICC profile to a monitor.
Argyll is a command line tool and driver to be used with professional hardware calibratrors. (spectrophotometer, colorimeter). I have yet to try it though I would very much like to one day.
Lprof and xcalib didn’t work for me. Either Lprof didn’t write a profile that xcalib understood, or xcalib wasn’t able to properly communicate to the video card. I suspect the later, as on xcalibs site it is noted that xcalib has trouble setting a couple variables on older ATI cards.
All is not lost though as the gamma setting can be set to make up some color differences in the monitor.
Most distro’s already have xgamma installed so begin testing xgamma by:
xgamma -gamma .95
Xservers default is 1.0. Use a gamma chart to correctly set the gamma.
Most charts are configured to be set to 2.2, the basic standard now days. Macs still use 1.8 which can make things screwy even when I used Mac OS I had a 2.2 gamma set up.
Xgamma can adjust color gammas too
-ggamma but there is alot easier way to do that
Monica, my honey my sweetie. Monica is a graphic front end to xgamma:
Careful with Monica she can be sensitive – the color boxs are tad off. I find it easier to detect color skew with the gray scale bar on top. Thank ya honey, you can go now. ;)
Monitors and LCD’s do change over time. It’s not uncommon in desktop publishing house to see people calibrate their displays every couple of weeks. But now that gamma has been discovered a good way to set it is to put it in the Monitor section of
Section "Monitor" Identifier "Color LCD" Option "DPMS" HorizSync 28-84 VertRefresh 43-60 Gamma 0.78 0.92 0.95 #RGB EndSection
Once I had created a profile, Lprof refused to write to file. Probably a missing dependency but easy enough to fix:
Then on the select file button (…), I selected
ibook.icc and then was able to “Create Profile”.
Notes and Resources
- For Mac users manual calibration is best done in OS X. OS X provides an excellent color profiler (having a grayscale in the background makes it even easier.
- Wikipedia – Linux Color Management
- Calibration Basics
- ArgyllCMS and Linux – Spyder2 – The Good and the Ugly
- Windows too may have monitor calibration? XP Vista? Haven’t tied it though.