Calibrate your monitor

Calibrate your monitor so that photos, videos and everything else in color looks right.

Mac users have a manual calibration tool that gives very good results. Windows users have no calibration tool, but Adobe has a gamma calibration tool that's included with Photoshop that can be used for acceptable results.

Manual calibration can be done on your Ubuntu desktop as well. Follow these steps.

Basic calibration

Calibration should be done on a monitor that's warmed up (turned on for 15 minutes or more). There should be no bright lights or glare on the monitor.

FIRST: Screen resolution

Check your screen resolution and make sure you are using the highest resolution available for your monitor. Under the System menu, in Preferences select Display. Check the Resolution and select the highest one (that's the one with the most numbers).

SECOND: Monitor settings

Using you monitors controls, set the color temperature (white point) to 6500K, D65, or sRGB, whichever setting your monitor uses.

Then turn up contrast to the maximum setting. Open a monitor calibration chart, such as the one found on PhotoFriday.com. Viewing the top bar on the Photo Friday chart, slowly turn down the contrast setting from 100 until you start to see a difference on the bar at position Y and position Z.

Next adjust the brightness control. Adjust the brightness up or down until you begin to see a slight difference on the bar at position A and position B.

Using Xgamma

Xgamma is a software application installed on all Ubuntu systems that can be used to change the gamma settings. This is another way of setting the black level. Open a terminal window from the Applications menu under Accessories. Open a black level chart and then in the terminal window, at the command prompt enter:

xgamma -gamma 1.0

The default gamma setting for Xwindows is 1.0. This should be adjusted up or down until the bar A in the chart is black at the level of 2.2. On my monitor, for example, this is best at 0.9.

Color profiles

Photographers, videographers, graphic articles all use color profiles for consistent color. Setting your monitor to use a color profile means that every time you restart the computer, the same color settings will be used by your monitor. And the color settings you use for the monitor can be coordinated with your scanner, printer and camera.

Color profiles are three-dimensional color maps that translate color from one device to another. The International Color Consortium, usually referred to as ICC, has defined standards for color profiles that translate color from one device to another. The Linux desktop can use ICC profiles. For more information see the OpenICC project, part of freedesktop.org.

ICC profiles are designated by an .icc or .icm file extension. In order for a device to have access to the information contained in the profiles, you have to get an appropriate profile or create one and then save it in the correct directory on your computer’s hard drive.

LPROF

Lprof (Little Color Management System Profiler) is an application that can be used to set up color profiles for the Ubuntu desktop. First, you must install the program. Use the Synaptic Package Manager and Quick Search for lprof. Select lprof and the related packages needed, then click Apply.

Start Lprof from the Applications menu, under Graphics. For setting a monitor profile select the Monitor Profiler tab. For most, select the button to "build a coarse profile." This option lets you select from a number of predefined profiles or to define your own. Click on the Enter Monitor Values button. Set White Point to D65. Set Gamma and Black Point to 2.20 for all three - Red, Green, Blue.

In Primaries, select the predefined profile you want. the default is ITU-R BT.709 (sRGB). If you aren't sure use that or the Adobe RGB profile.

Finally, click on Create Profile. Give it an appropriate name with the extension of .icm (the M indicates it is a color profile for a monitor) or leave it as default.icm. Save the profile into $home/.color/icc or if it is to be made available for multiple users of the system into /usr/share/color/.icc.

Remember the name of the profile because once it is defined you then have to load it. The last step is to set the system to load it on every startup.

Download profiles

Alternatively, you can download color profiles and use one of them. Scribus, the open source desktop publishing program, maintains a library of free color profiles available for download. Available at Scribus color profiles.

Load profile

Once you have a profile, you'll have to load it so that the video card will use it. Xcalib is a utility that will load the color profile. Xcalib is not included with the default Ubuntu installation. Install it with Synaptic Package Manager. Quick Search for xcalib. Select xcalib and click the Apply button.

Once installed, open a Terminal window from the Applications menu under Accessories. To load a color profile to your video card enter:

/usr/bin/xcalib ~/.color/icc/default.icm

Of course, use your profile name in place of default.icm if it has a different name.

ADD TO STARTUP

To load the color profile to the video card every time you login to the computer, go to Startup Applications in the System menu under Preferences. Click on the add button.

In Name enter Color Profile. In command you need to enter the same command as above but use the full path for the location of the color profile. For example, if you have a systemwide color profile defined, enter:

/usr/bin/xcalib /usr/share/color/.icc/default.icm

Or, for a personal color profile, enter:

/usr/bin/xcalib /home/your_username/.color/icc/default.icm

Then click on the Add button.