U3014, Spyder 4 Elite, DisplayCAL, calibration issues

From your screenshots it seems that your DUCCS configuration could be partially wrong and that you are using an outdated version and that you are mixing difrent calibrations, hence the test is not valid.

-in older versions (before 1.6.5) "native preset" aims for whatever Dell names "native". If you wish a custom white and do not want to try new version, set it manually. For example try AdobeRGB, sRGB or "custom xy" with xy coordinates for srgb/adobergb and D65 white.
-it seems that you have attached 2 monitors while running  DUCCS. That is not recomended, unplug the older. I think that it was inclused in some official FAQ from Dell /but not 100% sure). Also there is a sRGB CCFL correction selected in UI which could cause all sort problems.
-CCT in dark colors does not work like you think (actual black is bellow 2 delta b* from your target)
-DisplayCAL profile shows a warm whitepoint (5500K daylight) which should look yellower than D65 (6500K daylight), so device seems to measure OK with proper correction. That yellower whitepoint is written in profile name, so calibration is OK when we talk about white.
-profile in DUCCS and profile in DisplayCAL do not match. They are not the same calibration.
-a*b* tints in grey ramp are typical of older verions than 1.6.5. Newer DUCCS or GPU calibration (old way without HW calibration adn DCCS) could improve that. GPU calibration grey ramp results are dependent on GPU HW and calibration "speed" configuration.

@yumichan 

Thank you for your reply. Your time and help is much appreciated. I will go through all of your points one by one tonight and will redo it all.

One thing though, is that I wasn't able to use new DUCCS. It wouldn't connect to my monitor. Here on this forums, I found info that the latest one that can connect to u3014 is 1.5.8. That is the reason why I downloaded and installed it. 

It doesn't break in the middle. If you refer to the crash I described above, it only happened once in 5 or 6 calibrations I attempted. Each and every one was successful, ie it went all the way to the end, except for this one time.

It just seems like when ICC profile is created, it gets modified / broken by something. During calibration whites are white, calibration finishes, last step is to create profile and load it and then it turns yellow. It happens with every software and calibration type, HW calibration, GPU calibration, DUCCS, DisplayCAL, iProfiler. The only thing I have not tried yet is to get my Spyder 4 Elite out, install its software and try that. However, it's all packed and ready to be sold.

OK, I'm going to do the DisplayCAL calibration now.

If it breaks in the middle of operation find logs and send them to Xrite/Dell. HOME, "AppData\Roaming\Dell\Dell UltraSharp Calibration Solution".

I've no acces to DUCCS code. Your display and mine have no public SDK available so you cannot write to monitor calibration by other way.

Use GPU calibration... Custom mode, all to default, move just RGB gains keeping one al 100, move brightness from 50% to your desired level at the same time you tune whitepoint... measuring with DisplayCAL d65 traget an RG_phosphor as correction.
This leads to white at the point of measurement.

@yumichan

I am so confused by all of this that I honestly am out of ideas.

Here is what I've done.

- Disconnected the second monitor.

- Changed color profile back to the basic u3014.icm - whites changed to yellow

- Fired up DUCCS

- Changed from "native" to custom xy. Got AdobeRGB coordinates from Wikipedia (please see the screenshot attached). Changed to D65 as suggested. Changed luminance to 100cd/m2, just to see if there will be a noticeable difference

- started calibration. Calibration finished, but I have messed up the screenshot, so I decided to redo the calibration again. Whites were yellow just as every other time.

- so started DUCCS again, everything the same, but this time I have picked the biggest patch of colours to measure from. Just to increase accuracy.

- Started calibration. 2 or 3 min into it, calibration stopped with an error message, something to do with DUCCS lost connection with monitor... what I was shocked to see is purest whites I have seen for long time. The whites were perfect after it crashed and calibration stopped in the middle. I have restarted the calibration and of course when it ended, whites are yellow. This is the post calibration screen. It reports that it achieved 6600K! Where?! Definitely not on the screen I'm looking at. I reckon it was 6600K when the calibration crashed and I saw whites as they should, but the minute every calibration finishes with whichever software, it always look yellow. I reckon it measures the white point during the calibration and not at the end where every calibration turns yellow. It's that last step when profile is being created and loaded into Windows, that whites change to yellow

I have also loaded Profile Info from DisplayCAL

I have also restarted the PC to make sure that the profile is loaded correctly into the system. Checked in Windows settings and correct profile is loaded (one created by DUCCS few minutes ago)

I was planning on doing DisplayCAL calibration straight after, but even without trying it, I know what the results will be.

Aaaaand whites are yellow.

I don't understand why everything reports that it's 6500K when it clearly isn't.

I've done everything like suggested. Using gains, I have went to as close to middle point for  R G and B as possible. Then let the calibration go. This time the white remained just the same as after DUCCS calibration. Nothing changed at all. DisplayCAL reports 6500K. Those are profile info screens straight after calibraiton:

I then went on to to even more comprehensive verification than before. It also reports that it is 6500K

To be sure that I'm not losing my mind here and my eyes suddenly see everything yellow, I have fired up my Dell 4k wide gamut laptop calibrated using DisplayCAL and Spyder 4 Elite a couple of months ago

Laptop bellow, u3014 calibrated to 6500K above

Since that dell 4k is not calibrated with the proper spectral correction and since spyder4 is not accurate at all, your comparison is useless. Laptop could not be D65 at all but something cooler.

If whites are white in U3014 during RGB gain fine tune and during patch measurement there should be some configuration in your Windows that moves screen to warm white. Dell Display Manger could be used to disable some anoying feature movie effect or something like that, check out this. It could be diosabled form OSD too.

ArgyllCMS has comand line tools that takes single measurement without drawing a window patch. If your screen is really yellow while not measuring patches as you report AT THE MEASURING POINT, this way you can capture it. I think it was "spotread" but check documentation.

If your screen (U3014) has an extremely poor color uniformity it could be D65 at the measuing point but other white in other screen zones, hence the overall color cast you report.
2013-2014 versions have a not so useful Uniformity Compensation, since it usally locks brightness when activated. This means that form a practical perspective, uniformity issues are non correctable.

U2412m was better tan U3014, only 76%rgb but was constant. This one is changhing color when i change brightnes. So annoying.. Is ok only for productivity.