Friday, October 9, 2009

Monitor calibration on Windows 7

Here I try to highlight a few changes in color management system that I’ve found useful and explain settings for the single and dual monitor setup.

New features you may use for calibration

Windows 7 has a few major improvements over Windows XP in terms of a monitor calibration:

Color Management applet. You don’t have to download anything from Microsoft to get multi monitor support anymore. It’s all done in one place. There you can assign profiles to devices and fine tune the CMS. Below I explain how to use it.

LUT loader. Throw away all that third-party loaders you had before, Windows 7 does it for you now. If your displays’ profiles contain LUT information it will be loaded after the user selection screen and just before the desktop will show up. For the dual-head video card owners for whom it was impossible to load two different LUTs in Windows XP, it works just fine in Windows 7.

ICC v4 profiles. The updated ICM 3.0 now supports v4 profiles which you can create with ColorEyes Display Pro for example. However, be aware that not all programs support v4 profiles at this point and Firefox 3.5 is a number one to mention.

Software color calibration. This is what Macs had for ages and Adobe Gamma did on PC. Even if you don’t have a hardware calibrator you still can get a good result by doing a visual calibration.

Windows Photo Viewer. This viewer does one thing that others don’t. It chooses the profile depending on the display the image is located on. Take a look, two monitors next to each other. The profile on the left is sRGB, on the right is BGR (i.e. red abd blue channels are swapped).


There are still some problems though. The old Vista bug when LUTS are reseted after wake up from the sleep mode. On a dual monitor system (at least on dual head) only the main monitor’s profile is used by color managed programs like Photoshop or Safari, no matter where actually you have them open.

Color Management applet

Once you have calibrated your monitors, launch Color Management applet. To apply your profiles system wide, go to Advanced tab and click on “Change system defaults”. In the new System Defaults window add profiles to the corresponding devices in Devices tab. If you have several profiles for a device, don’t forget to choose one to be default. It would be used for the LUT loading.

Switch to Advanced tab of System Defaults window.

Color Management applet, screenshot

Check “Use Windows display calibration” box. This turns internal Windows LUT loader on, which is a nice brand new feature in Windows 7. Don’t forget to remove Adobe Gamma, Colorvision or any other LUT loaders from your system (they are usually located in Startup folder), no need for them anymore.

It is better to leave the rest of the settings on this page at their defaults.

Device profile: If a device have no profile specified anywhere else this one would be used. Leave it as sRGB. Setting a wider space like AdobeRGB here would likely result in desaturated colors on the device and having your monitor profile there is simply wrong.

Viewing conditions profile: This one tells the system about your viewing environment. “WCS profile for sRGB viewing conditions” works for a sRGB monitor in standard viewing conditions. “WCS profile for ICC viewing conditions” is appropriate for a print in a D50 viewing booth.

ICC Rendering Intent to WCS Gamut Mapping is explained in the help, or visit msdn for a more detailed explanation. Leave Default rendering intent as Perceptual.

If you need to make changes for your account only, no need to change system defaults. Assign your profiles right at the Devices tab.

Testing tools

If you are interested in testing your system, there are a few things you might find useful:

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