Can't think of a better place than Lowepost for these things, it's really mentioned everywhere, you just have to know what to look for.
From the Hobbit article:
"Luma curves are one of my favourite tools to use in achieving a richer, bolder look. By grabbing a still of how a shot sits with the desired exposure levels etc and playing with the curve in conjunction with Lift Gamma Gain, you are able to get some extra tone into areas of the picture that the standard tools can’t reach alone. Often you end up in the same place as your still with no perceivable difference, but sometimes, with enough experimenting, you can come up with some beautiful richness and depth and still keep the same exposure level to what you started with and desired in the first place, just a much richer frame in certain subtle areas. This doesn’t always work so you have to be judicious."