I have 2 accounts on my Mac Pro both are using the same color display profile however on my account it is clearly a lot brighter. I can test this by switching between the 2 accounts with the same image open in both accounts. On account A you can see the light shades of gray on account B the light shades of gray are missing and it just looks solid white.
I removed everything from account B's startup items and looked at the processes running on a clean boot into both accounts and the only differences are processes I expect to make no difference (mysql, perl etc.)
When I login into the account B (with the problem) that does have the problem I see the brightness change 2 times before finder and the rest of the desktop starts, whereas logging into account A doesn't seem to do this.
I would like to know what is causing this and stop it as it's very annoying.