I am imaging a lot of old negatives.
You can invert the tone curve in lightroom and get a usable image, but having done so the sliders do not work as expected, some backwards, some just wacky.
You can also invert the tone curve in a DNG Camera Profile (if shooting the negatives raw), and it appears to do the same thing; specifically the sliders do not work properly.
You can invert the tone curve in Photoshop, and thus commit to a TIFF (or JPG) image for further editing, which does then allow the lightroom (or photoshop) editing controls to work as normal. Photoshop is also pretty good at removing color cast if you have neutral tones to sample with curves. THere is a lot of information along these lines in prior answers (e.g. starting here).
My question though is whether it is possible to keep the raw image and edit in Lightroom, but make the controls work "correctly", effectively to invert it transparently, as though one took it to photoshop and did the inversion, but somehow got it back as a raw. More specifically, can it be done somehow in the camera profile?
Inverting the tone curve in the profile does not achieve this (the sliders are still backwards). Could one somehow map all the colors to their inverses (perhaps even then correcting for color casts in some way)? You cannot do that in the editor, as it limits the distance you can drag a color, you cannot go to the opposite side of the wheel, but I do not know if one could manually (i.e. with a program) produce such an opposite profile?
I tried taking an image of a color chart, inverting that, and taking a photo of it to build a profile - the profile will not build (interestingly the Adobe editor opens this inverse image and MOSTLY corrects it to the right colors for display, inverting it itself; but it will not proceed with a profile).
Is there some manual way to build such a profile? Or would I be back to the same place as inverting the tone curve, that the sliders still do not work correctly, even if the profile resulted in a positive image?