OK, my bad .. it does work in CNX-D .. which is a bonus
This way you maintain an NEF file workflow to the final output.
( actually forgot the specific process and thought it didn't work, but anyhow .. my bad)
Process is to get the NEF in CNX-D in negative colour.
The, the first two steps are invert the levels-curves graph and WB using dropper.
I find it's easier to do graph reversal(which does the colour reversal for me really well, then the orange cast turns to a blue cast(which is fine).
Just remember you want a white/grey/black reference point because the colour shift is very dramatic. I've yet to find an actual WB K value and tint setting that works using manual inputs.
Using the dropper to get close to a good WB edit, then tweak using the sliders(I just keep clicking near the point I think is 'whitest').
In my sample images, I clicked the door knob, but may have missed by a pixel compared to my actual edit of this negative, but then clicked on the white paint on the door, got better, just a bit too warm, then clicked paint again and got pretty much as this room is.
Images from this point are now colour reversed using just those two steps, and from here it's a matter of tweaking to bring out colour and contrast, as you see fit.
But there are a couple of caveats(which you would find anyhow) .. just a heads up. **
Hopefully you can read my embedded text.
point is to note the std curve is from low on the left to high on the right. black to white. This is what you need to 'invert'. Basically you force black to white and white to black(on the RGB channels).
CNX2 is a little easier to work with this tool, on my PC(I have a 4K screen, and CNX-D doesn't scale well to it).
So in CNX-D what I do to get more control is to undock the levels-curves, get it into the middle of the screen, enlarge it as much as I can, and then grab each corner point with the mouse and drag up(on the LHS) and down(on the RHS).
What you're looking for on the CNX-D tool, is when the mouse cursor becoems the cross tool.
You may have a different experience than I have tho .. hardware dependent.
On my screen it's very fine/finicky to grab the actual points required to be dragged, so it's a bit hit and miss. If this happens for you, just keep persevering, it does work as shown below.
Next tip in using this tool. which ever end you drag first, don't drag it all the way to the opposite extreme to begin with. Just makes it harder to locate the opposite corner point.
eg. if I start with the blacks first, lower LH corner, I only drag it about 2/3rd of the way to the top of that LH scale. Then do the opposite for the brights, drag it down close to all the way to the lower corner.
Go back the darks 2/3rds of the way up and drag it further up. if you drag all the way, the mouse may be hard to locate onto the correct point of the curves tool.
All this will make sense once you play with a few times.
Also, on the first point alteration, you may see the screen go full white if you start with the blacks, or full black if you start with the brights. normal, will come good once the opposing point is adjusted.
This is basically done. the blue cast is now a WB setting. I think for me, because a used a halogen light source when I digitized the negative with the camera? .. not sure, but different light sources will have various WB effects.
Note the difference in the levels-curves gradient now. black is high, white is low. You can also tweak it's mid settings, to add/reduce contrast as needed too. I found some films NEEDED this to get contrast back, rather than add contrast via other means.
But overall, I use Picture Controls more and the other basic NEF edit tools.
Note too, some of the tools work in reverse, because you've reversed the tone scale. Exposure compensation is reversed. if you want brighter compensation you need to reduce it. ie. +1Ev compensation will darken the image now. The anomaly I've found is that the reverse use of the tools is random. Brightness works as normal, but then you may find that highlight and shadows works in reverse. ie. shadows darkens the image protecting highlights and vice versa!
Nicely colour reversed, just lacking saturation and contrast .. easy fixed with tweaking.
I use a combo of Picture Control, CCPs .. etc.
Note the location of where I used the WB dropper tool, even tho my reversed image was blue. This is my back door, and handle is metal grey, paint is white.
Chairs have a mid tan(timber) partly warm orangey tone, some cloth on the backrest is red .. etc.
Some fiddling with Exp Comp, tone, etc. and the image is pretty much as is the print version of this negative.
The film used here was Extar 100, and I could extract more detail from the NEF shot in camera using the PB4, and a paddle(icecream stick) to burn the highlights (outside the door).
Note tho the CCP on the fence outside. That was to reduce brightness a little more, and to increase contrast a small amount.
One last tip. The hardest part is really the level-curves tool. It's most likely going to be the same setting over and over. I'd recommend to make this adjustment first, and none else, and then save that edit step.
In CNX-D this is a bit more fluent as a batch edit job to do, than in CNX2 as well.
if you find this processing system works for you and you have multiple images to process, what you'd do is to create that levels/curves edit just the once. In the drop down menu where it says [Recorded Settings], hit the drop down and then click [Register].
Choose a name for the save file(I used Negative Reversal), and done.
Now, for your captured negatives, use the film strip, click on each image(to highlight) that you want to colour reverse
before you do anything else.
Cntrl-A to select all of them. Then open the Levels-Curves tool, use the drop down to locate you saved "Negative Reversal" batch save, and all highlighted images will receive the save process.
They all shift from orange to blue(or whatever other tint they start with) .. but from this point it's the easy stuff of WB and tweaking.
I find the most annoying part is just the finicky levels and curves setting.
I also did the same in CNX2 as well, but as said earlier, to do this is in CNX2 requires a few more mouse clicks .. CNX-D makes it a couple of click affair .. easy as!
Hope that helps, really is easy to do.
When I get a chance I'll post the print version of that negative for comparison too.
