- In the preferences I checked "Avarage low luminance measurements" ("Improves the accuracy of low luminance measurements by taking several measurements and averaging them."
- I set 52 calibration and profile steps instead of 32.
- I changed the calibration priority from "maximize contrast ratio" to "Best grayscale color tracking" (That was a winner I think?!)
these were the crucial changes, especially the first and the latter are essential.
I just validated the calibration again, and again and again. This time with the NEC puck, and things look like this:
White point Delta E: 2.95, 3.32, 3.12, 3.79
Maximum Grayscale Delta E: 2.95, 3.32, 3.12, 3.79
Average Grayscale Delta E: 2.19, 2.67, 2.55, 2.89
I have a third colorimeter, a regular i1D2. Here is the validation:
White point Delta E: 8.28, 7.64
Maximum Grayscale Delta E: 8.28, 7.64
Average Grayscale Delta E: 6.63, 6.17
New validation with DTP94b:
White point Delta E: 0.29
Maximum Grayscale Delta E: 1.09
Average Grayscale Delta E: 0.65
Hmmm...

So I did a new calibration with the NEC puck, and Delta E is at an average 0.86 and a max 2.86 (including dark values). DTP94b validation is White Point DeltaE:2.87, Max Grayscale DeltaE:2.87, Average Grayscale DeltaE: 2.04
when you are calibrating with device A the validation with device B is absolutely irrelevent!
You are wasting time!Obviously the DTP94 makes the better greyscale, especially in the dark tonal values (which is no surprise).
So if the NEC puck and the DTP94 produce roughly the same results WRT to colors I'd use the DTP94.
I followed your advice and lowered the contrast a bit, to approximately 0.4. Consequently the Delta E readings of dark values got better. A got averages as low as 0.4-0.5. As a matter of fact the bad deep blacks, just got cut off.
Sounds very good!
Do you see what that means?
If you want to calibrate the monitor to (for instance) 5000K but the display has a generic white point of (for instance) 6500K (mostly even bluer in the blacks) the software has to adjust the hardware... i.e. it has to adjust the RGB channels of the monitor from RGB 0-0-0 to RGB 12-8-0 (or whatever... fictitious numbers). Strictly speaking this adjustment does not apply to the actual RGB channels of the monitor (only the white point is adjusted by the RGB channels) but it applies to the RGB channels in the LUT of the monitor.
So a neutral black - without any color cast and consequently whithout such a high DeltaE value - is always brighter than the absolut black (as said RGB 12-8-0 is simply not pure black).
It's up to you whether you prefer a bad calibration curve but higher contrast or prefer an accurate calibration curve but a lower contrast.
I think it's quite clear which one I would prefer.
BTW, a black level of 0.4cd/m2 is absolutely not uncommon for IPS panels. Maybe this new NEC is advertised as an IPS monitor with a lower black level. But if you can utilize the low black level only at the generic white point it's useless... IMO.
You have to get used to the somewhat lower contrast. But I promise you will get used to it after some time.
Now, as to a "match" with the prints, contrast wise, I bet the monitor still has a much, much higher contrast.
If you feel prints and monitor match better when you set the softproof to rel.col. + BPC (for the conversion) but leave the simulation of paper white and even the simulation of black ink unchecked, than go for it. It sounds a bit strange to me, as in re.col. viewing on the monitor (so without SPC) simulate black ink should match better.
But maybe, probably, this is something you have to get used to.
How does monitor and prints match if you move back from the display 1 or 2 meters? Maybe you are just far to close to the monitor. I don't know... you have to find out what works best. As mentioned several times in this thread monitor and prints will never really match 100%. Find out how to get the closest match
for you...
The yellow cast of the screen, making the paper appear bluish and cold, got almost solved by again lifting the temperature. Its now 6000K and good match for now.
makes sense.
There is one last thing which I can't correct. That is that the print seems to show more red everywhere, more saturated reds, in the shadows, highlights and mid-tones. And the screen definitely lacks the reds.
I hope you have a good advice for this

yes, but first you should check if all your prints, i.e. all your papers show higher saturated reds.*
If so, you can adjust the colors of the monitor profile. Again, I don't know the NEC software but my software provides the adjustment of 6 color channels (hue and saturation). But actually one would fine tune the monitor profile for each paper individually. This is also not a totally easy task... when you say "red" the magenta and yellow might also play a role here. So boosting the saturation of the red channel will most likely not give you an accurate result. Most likely it will make things worse...
So my advice is to skip this for a while and first get accustomed to your new setup. It's possibly easier (less "destructive") to just create a color layer in Photoshop that you simply add for softproofing purposes, i.e. to simulate the actual print saturation (of course you have to delete or deactivate that layer prior to printing the file !!! ).
*edit: of course you should also check whether these colors are inside the actual gamut of your monitor. If you are talking about reds your display is not able to produce, than any adjustment won't help.
Check it this way: first convert the file to your printer profile (rel.col + BPC). Secondly set your monitor profiles as proof profile and enable color warning.