Recently I'm working with various images that need precise gamma correction, eg: scanned pictures that require a gamma shift from 1 to 2.2, it's a common problem around people who works with linear scan files.
Photoshop has the exposure correction layers/adjustments:
Lightroom lacks of this option but it has curves:
I read around that i can mimic the effect by dragging around the sliders in some way and such.
What I would like is a serious reproducible, numeric (if possible) and precise way to do a gamma correction in lightroom. (basically i would be able to superimpose the file and obtain the same pixel colors I had if the gamma correction was done in photoshop with the exposure adjustment).
Side note: Edit the file in photoshop for the correction and do the edits later in lightroom is not an option. I want to keep the original uncorrected version, aswell as I don't want to store 2 times the file (uncorrected+corrected) because them are huge and it's a waste of memory.
I want to take advantage of the virtual copies of Lightroom and keep together an uncorrected and a gamma corrected version of the image just with the storage of the original uncorrected file and some light lightroom metadata.