I
think your bug was already filed as issue #
655417. It seems similar in that it is Chrome on MacOS, gamma is too high, and it is fixed with acceleration turned off. There are relevant comments in the discussion thread, so you should probably read it.
If you haven't filed a bug yet, and this one is indeed the same as your bug, you shouldn't file another one. Google explicitly states that filing duplicate bugs does not increase the priority and it actually slows them down.
If my guess is incorrect and this isn't the same problem, then go ahead and file a new bug in this system directly. Read through
the guidelines first.