Saturday, December 19, 2009

Gamma table bug continued in Windows 7


For users who set up a custom color profile - whether by installing their own color profile or calibrating it via Windows 7's "Calibrate" option in the Display control panel might probably know about this bug which even Windows Vista had. In short, you lose your calibration settings when you lock the computer and unlock it. I have noticed that only the gamma settings get lost.


This bug in Windows 7 is due to a problem with how the ICC profiles are handled. The ICC profile not only tries to match the device colors but also applies the right amount of gamma. The second part doesn't work correctly in Windows 7.


Microsoft has yet to acknowledge the bug.


How to replicate the Problem:


1. Set up a custom calibration (ICC color profile) by going to the Windows 7 Control Panel->Personalization->Display and choose Calibrate.
2. Change the gamma settings.
3. When you lock and unlock the computer, the gamma settings are gone.


Possible solutions:


1. Microsoft has not released and update patch to fix this gamma bug. So you can wait for them to send a patch in the future.

2. For now, download this Utility called DisplayProfile. I usually run DisplayProfile.exe from my TaskBar. It is a standalone executable. After running it, click on any other profile and choose your current profile again. The gamma settings are automatically applies.

Here's a screenshot:







Happy profiling!

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