use a gamma control panel.

Gammawork was the best solution i found.

http://www.versiontracker.com/dyn/moreinfo/macosx/20100

I used this application to create my screen presets, which i then stored into catalyst.
They did not respond to requests to 'register' the application

I did build in 20 screen presets - which are not editable - at the moment -to allow realtime changes on video output levels.

http://chaldee1.gotadsl.co.uk/~richa...=1638#post1638

apple's coloursync utilities dont have the correct level of control for doing video gamut corrections.
i.e. converting from YUV to RGB colour spaces.
Or extending an YUV source to output the full range of RGB values ( 0..255 ).