Calibrated two Dell U2415 monitors but they both look different.

[Space Squirrel]

I bought two Dell U2415 monitors because supposedly they have accurate colors and come factory calibrated, to a DeltaE < 3, so I thought I wouldn’t have to worry about calibration. However even from the factory they seemed significantly off. If I put a white window across both of them, one looks more yellow, and the other looks a little more rosy red.

So I used a ColorMunki Display colorimeter to calibrate them with the same settings, but after finishing they still basically have the same difference in tone.

Here are the settings I used, based on what seems correct and standard after doing lots of reading and youtube videos

Settings: sRGB (I hear supposedly Gamma 2.2 could be chosen also and is almost indistinguishable, but various threads made me lean to sRGB)

Correction: Spectral: LCD White LED family (AC, LG, Samsung)

Everything else was default, which included in the calibration menu Whitepoint as “Chromaticity coordinates” and White level “as measured”

As for the monitors, they were set to custom color and I adjusted the rgb values as accurately as possible for the arrows to line up, and I had brightness at a level near 120 cd/m2

Perhaps some of these are wrong?

I noticed when viewing the profile details later in displaycal loader > profile associations > profile information, that Media white point Illuminant-relative CCT is 6569 for the yellower monitor and 6472 for the rosy monitor. So I suspect maybe I did white point wrong. I hear it should be 6500, so maybe I should have manually set it?

I read one thread about using the visual white point editor if there is a mismatch but I don’t really trust my eyes since I know how much your eyes change based on environment. I have a feeling maybe I need to just set it to 6500 manually but couldn’t find this documented, and randomly experimenting takes a lot of time.

Can anyone help explain in simple newbie friendly terms what I’m doing wrong, or what settings I should be changing differently in order to achieve a proper calibration so both these monitors are equal and properly calibrated? I’m not trying to do professional work, I just want reasonable assurance they are color accurate for all my personal and family photos/videos.

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[Vincent]

CCT is not a reliable way of measuring white. You only take account of “b*” axis and ignore a* axis.
Make a measurement report and calculate actual color distance between measured white (between displays) and profile white (between displays), lots of online calculator like bruce lindbloom. This will give you a hint if its an issue of colorimeter (match) or caused by you when operating RGB gains while leaving calibration target to native or something like that.

Also try to search for an specific 3nm CCSS (not CCMX) correction for your U2415 in colorimeter database.

Aiming for 6500 daylight, 2.2 curve and single curve matrix + black point compensation seems a good start. For white mismatch choose the whiter as reference and visual white point match. Since that 2nd display has close to a match numarically on OSD RGB gains, correction should be small on a*b* axis.

Also displays can match on the cernter ( numerically & visually) but due to poor uniformity seenscreens as a whole you can percieve a tone mismatch. This is not correctable.

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