Is there a simnple way of correcting the gamma setting on a Mac projector?

I have developed my presentation in Windows, and it looks great on Windows,
but the higher gamma setting on the mac tends to make the images look a bit
washed out.

There is a thrid party Xtra which does it the other way around (changes PC
setting) for those who delveloped on a Mac, but I need it the other way.

Any one have any knowlege of this?