(By the way, this is one of the mediocre lightroom ones, some are pretty decent, some are awful, but this is 'average'. This is too much of a niche need, but I bet all lightroom really needs is an 'invert then ignore the inversion' mechanism, and it would work great for this.

Photoshop also works better, because you can invert the tone curve and then all the tools work normally. T he color cast looks easy to remember, but remember none of the controls work as you expect, try to fix one color and another gets much worse. Here's an example, left is Vuesan, right is my attempt in lightroom. I feel like Lightroom has all that I need here, between the curves and HSL and other slides, but what is needed is to get the order right of making the adjustments. What's odd is once in a while (I think poorly exposed) I can do a much better job in lightroom, though it is tedious. For the vast majority I just gave up and used Vuescan, which does a pretty decent job on them. The more I do this the more I feel like I am just on the edge of finding a good approach, but not quite. And with which control? How do I remove bias in the tone curves - keep it linear at a 45 degree angle and raise/lower both ends, change the angle, some sort of curve? do I set black first? And do I set it as white (pre-invert) or as black (post invert). There's got to be, algorithmically, a 'best' way to do this, that preserves the. Which is the place that, having adjusted, gives me the most 'normal' adjustment for fine tuning later.

But I can do that with temperature sliders (somewhat), with the tone curve itself (and there I can do it by either changing shape of a color or biasing the color while keeping it linear), or with the HSL sliders. I think I want the R, G and B to exactly overlap (though it's not clear where on the histogram I want it, left or right wise). Let's take the neutral, say I actually had a grey card in frame - I can crop to just it and look at the histogram. What do I tackle first, and with which slider. In terms of how ACR works, is there an optimal way to make adjustments. There's tools like Vuescan which actually do this very nicely - but again, the output is TIF or JPG. moving toward yellow gives below, more exposure less, etc. It is easier in photoshop, since the curve inversion is destructive and once inverted you are just adjusting a positive (as opposed to lightroom where you are seeing a positive but adjusting a negative, e.g. In practice the inter-relation of each change makes it hard. In principle it is easy - invert the RGB tone curve, then adjust the colors to take out the negative tint, and adjust the rest as desired (with some controls now working backwards or just different). I like doing it with lightroom as the non-destructive nature is SO much smaller than the huge TIF's you get out of negative scanning (or conversely is more editable than the JPG's you might get). I'm digitizing lots of old negatives by photographing them.

Lightroom invert colors