i feel i need to pop in here.
GC is a great tool, DS3 has it now as part of the advanced render settings, unfortunately most textures( skin especially ) have already been Gamma Corrected  in a paint program by the developer, so the added GC in the render has a tendency to screw up all the subtle tones and shadows, making them far too light. this is really noticeable if you are using a dark skin tone and can spoil the image considerably.
when content developers start producing textures that are not already GC, it will be a very useful addition.
has it stands now i have to turn GC down to 0.75 if i want to render a dark skin tone, and it can still be too light.