IME, but I have not tested it scientifically, Adobe profiles/curves tend to auto-adjust levels, likely to some preset standard i.e.; clip highlights by 2% and blacks by 3%. Any curve will shrink or stretch DR somewhere and maybe not where we want it. This is when linear comes to the rescue, allowing me to curve it taste, protecting values I want protected.
IDK about Adobe, but C1 allows you to precisely set your clip points for Auto Levels. This for me becomes a huge time saver, and I apply my auto level preference on import to all images. I additionally find that C1’s “film standard” curve is generally well-balanced contrast and saturation wise with excellent color accuracy. So it and auto levels are my goto starting point on import, and I rarely have to revert to linear to save or fix something. Another thing about C1’s film standard profile, is it is extremely consistent and produces very similar color and tonality results across camera brands. IME only FWIW.
Here are the exact settings, according to Adobe, required to reset the current Lightroom/ACR 'new Coke' flavor to the neutral defaults present up to version 2 of the development engine/process.
These settings are always applied on top of whatever profile or curve you select.
I.e.: You download a 3rd party 'flat' profile, and set curve to linear.
-> unless you apply the settings below to get to neutral, Adobe has chosen to apply the opposite of the corrective settings below on top of your image.
