Hi Claes,
instead of giving you recommendations for practical setups, I will try to provide you some examples of what result you get from a given adjustment and for different choices of the RGB colorspace. If you don’t mind, I will post examples every now and then, when time allows and/or when I get some good new idea for new use cases.
Let’s start from one of the simples adjustments: exposure compensation. It boils down to multiplying the RGB components by the same factor, which is expressed in powers of 2. For example, a 2-stop exposure increase corresponds to a multiplicative factor of 4. In the following I will apply this 2-stop adjustment to images in different colorspaces, with almost self-explanatory results…
Original image:
Image in standard sRGB colorspace, +2 exposure compensation:
Image in REC2020 colorspace with REC709 gamma encoding (the default), +2 exposure compensation:
Image in linear sRGB colorspace, +2 exposure compensation:
Image in linear REC2020 colorspace, +2 exposure compensation:
Notice how the first two images look different, due to their different gamma encodings, and how they both look “wrong”. The result of exposure compensation on linear RGB images looks instead correct and is the same regardless of the colorspace.
The bottom line: if you need to apply an exposure compensation, the correct choice is to work with linear gamma RGB data.