Usually, many path tracers over the CG market lack of any artistic control over the rendering.
There is nothing to have control of lighting on an artist point of view: contrast, flatness, hardness.
All you can do is working on Tone Mapping or on image post processing. It means that it is near impossible to preserve textures, colors or materials while doing such image degradation.
I implemented the ‘BOUGUER FACTOR’ in RIRE (Renderer inside Renderer).
The Bouguer Factor is a true control over Path Tracing for artist.
It allows, with:
- small value: very bright and soft lighting.
- bigger value: very dark (noir) and hard lighting.
All without compromising lighting realism (same number of bounces), while maintaining texture, colors and materials.
The use of the Bouguer Factor is just another good reason to do not have to add an Ambient Occlusion Pass to your rendering, and then have less render time. (Indeed, if you still need one, just use GAO).
Here are some examples: