"there is no reason it would need to be done before gamma correction whatsoever.  no matter how you break it down, it's all just pixels.  so you want to change stuff, you put in new pixels."
  
I'm not sure you understand what 'destructive' means in the context of CG.

"you have a nice gallery, and it's old enough that i'm sure you've improved, so i won't make assumptions.  but if you want to start a tech debate with bagginsbill, i warn you that you're very unlikely to encounter issues that he hasn't already researched to death.*"

My mistake, i didn't realize BB was the Infallible God of 3D that one questions at one's own peril. I'll just heed your warning and avoid 'tech debates' in the future, thanks.