(This article is specific to Windows PC users)

Regardless of which calibration system you are using, the calibration tables are stored in the monitor's LUT (Look Up Table). Only one calibration tool should use the LUT at any one time.

There is only one exception - if you have a very nice monitor (like an Eizo) that offers internal hardware calibration, then the calibration tables are in fact stored in the monitor itself, and all other LUT loaders should be disabled.

How to manually choose a LUT Loader

(and turn off Adobe Gamma)

On a Mac:

You don't have to do anything because LUT loaders are not used - simply go into System Preferences -> ColorSync and make sure the correct profiles are associated with each of your displays

On Windows 95/98/2000/XP:

N.b. If you re-install Photoshop for any reason, Photoshop will re-install Adobe Gamma automatically and you must turn it off again!

You can either manually browse the Start Menu -> Programs -> Startup -> [Right Click] and choose delete to get rid off LUT loaders you don't need. Or far simpler and more explicit, you can use this free ultity to precisely control which programs run at startup:

Mike Lin's Startup Control Panel [opens in a new window]

(Simply install, go to your control panel, and choose the new 'Startup option'. You can then manually enable/disable any programs you like!

On Windows Vista:

N.b. If you re-install Photoshop for any reason, Photoshop will re-install Adobe Gamma automatically and you must turn it off again!

You need to run the Windows Defender utility in your Control Panel and go to 'Startup Items' and disable or delete Adobe Gamma from there.