@AndN11
There is mild a* oscilation in light greys, about 0.8 delta a* an that is visible if you work with black & white image or illustrations.
I've explained the cause before, not preconditioned panel + too few measurements. If you upgrade your computer or buy a new one and you still keep that SW2700PT, I'll buy a Radeon, apply GPU calibration just for grey and get smooth neutral greys.
That a* oscilation is not dramatic, but it's expected for not preconditioned panels (I meant "cheap"). The wider the calibrated gamut is, the more notriciable these oscillations will be. For example CAL1 emulation sRGB by HW calibration (PME) should render beter a*b* range than what you got.
UP Dells, SW Benqs and all these monitos are "expected" to have a grey range with HW calibration between 1.5-2.1
and it should be less than 1. Of course some of them could have a grey range under 1 if their panels out of the box are very neutral
by chance, but 1.5-2.1 is the most probable outcome.
Black error may be influended by your calibration options inside PME.
An example of what grey calibration should be for monitors with HW cal, Tom01 example is very good:
dzisiaj, o 11:09
Dla porównania, poniżej wyniki NAJTAŃSZEJ kalibrowanej serii od EIZO, czyli CS:
We see there a 0.2 delta a* magenta-green oscillation which is superb. That is what buyers should seek for B&W work.
The only way to see these values in a SW Benq or UP dell is to assist/correct in GPU their HW calibration with a graphics card that has more than 10bit LUTs and temporal dithering (Radeons, from cheap ones to expensive ones...and maybe x0x0 nvidias if you use DisplayPort and force more than 8 bit per channel option, in my humble opinion Radeons are more reliable because of dither)
@Tom1 & @AndN11
That high error 12dE is not related to calibration but to PME "profile maker" which is faulty when creating ICC v2 profiles.
It is common that calibration software stores as device white the value of PCS white (D50), like i1Profiler derived software and if my memory do not fail Basiccolor display (& NEC Spectraprofiler) too. But they do it in THE RIGHT WAY:
since they are using PCS white instead of actual display white there is a CHromatic ADaptation matrix to (CHAD tag inside ICM file) do those conversions.
PME does not include that information (so profile is not as good as it should be)... and it just believes that since absolute colorimetric rendering intent from image TO SCREEN is never used, all things are going to be OK because from image to screen almost always is used relative colorimetric (so in photoshop ProPhotoRGB 255 white is rendered as display 255 white). Altough for most of apps this will work, you'll suffer severe errors if you build software LUT3D with that faulty profile (mostly for video work), like Resolve or madVR.
The easiest way to solve this BUG from PME is to "re-profile"
without GPU calibration in DisplayCAL (set
all calibration target to "native", and lower button will change from "calibrate & profile" to "profile"). This way you'll get a profile with actual display response in an idealized way (single curve + matrix) or in a detailled way (XYZLUT + matrix).
As I said it is not related to calibration but to one of those many bugs that plages Benq Software. PME is very inferior to Dell or Viewsonic calibration software counterparts: lacks of proper spectral corrections, builds faulty ICC v2 profile without CHAD info... etc
So the plot "Correlated color temperature" in page 5 is not fair, it is not testing calibration buf a faulty profile made by PME (the fault is im PME profiles, not in actual calibration white)
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As a summary we see in DisplayCAL report that you get what you pay, although green-magenta oscillations could be worse. That SW200PT PME calibration falls into C- mark. I've seen Dells with 2.01 range (D).
If people want A+ grey ramp like in Tom01 example (Eizo CS), money is needed... or apply GPU calibration with a suitable GPU.
Unfortunately color uniformity cannot be corrected by GPU and money is the only way to solve it right now. Maybe future GPU can load a uniformity mapping in its memory... but it is unlikely: for example modern GPUs have lut-matrix-lut HW and they do not use it, or use it in an obscure and not configurable way like AMD and its on the fly sRGB emulation for widegamuts (based on EDID data, not in actual measured data).