Lighting an Exterior Daylight Scene - Photographic Rendering with V-Ray for SketchUp - page 156

We do, of course, need to remember that any changes we make to the camera con-
trols will affect our entire render including any background images we are using. To
reiterate, my personal preference for handling any kind of color correction or experi-
mentation with tones in the scene would be to do so in post-production.