Lenovo P27u-10 Setup

[Imran Ramzan]

Hi,

I recently purchased the Lenovo P27u-10 which I am trying to setup as best as possible. This model is classed as wide-gamut (99% Adobe RGB, 97% P3) and comes with a factory calibration report outlining Delta E<2 for the sRGB and AdobeRGB presets. The P27u-10 is connected as a second monitor next to my iMac Retina 5K. OS X settings are tweaked: auto-brightness and Night Shift are off.

I used the latest version of DisplayCal with the iDisplay Pro colorimeter. There is a correction file for the P27u that I applied, and I used the Default testchart and calibration speed set to high. I ran a pass on the sRGB and Adobe RGB presets, the results look way off the advertised gamut and accuracy.

I then profiled a custom preset, adjusting the brightness/contrast and RGB (the sRGB and Adobe RGB presets are locked and you cannot adjust them), this was an improvement, but I still can’t seem to get gamut coverage close to the monitor specification, and Delta E are pretty high. I’m not getting 100% sRGB, let alone 99% AdobeRGB. I tried lots of tweaks, but can’t seem to get a nominal tolerance pass.

In comparison my iMac 5K returns as expected results (100% sRGB, 99% P3) and Delta E all below 2 after profile and verification. Side-by-side the P27u look oversaturated compared to the iMac screen, and too warm.

I have attached some files outlining my findings. Are there any Lenovo P27u owners who can collaborate their findings? Perhaps I am doing something wrong? Or this is ‘as expected’? Lastly maybe there is an issue with my panel and I should try and contact Lenovo. Any assistance greatly appreciated.

Thanks!

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[Vincent]

This model is classed as wide-gamut (99% Adobe RGB, 97% P3) and comes with a factory calibration report outlining Delta E<2 for the sRGB and AdobeRGB presets.

It means nothing, really.

There is a correction file for the P27u that I applied, and I used the Default testchart and calibration speed set to high.

Which one? Plot it if it’s a CCSS, maybe user who made it did it in the wrong way (non native gamut). CCMX are not really portable between other users and you.

I ran a pass on the sRGB and Adobe RGB presets, the results look way off the advertised gamut and accuracy.

How? Your sentence is very ambigous and DisplayCAL can do many things, but you may have chosen the wrong setup.
If you plan to verify factory calibrations to some colorspace preset you have to set a simulation profile and select it as display profile.
If you wish to verify a GPU calibration applied to soem preset you should never choose those settings becasuse it will clear your calibration.
Also your newly made displaycal profile cannot be used in other OSD preset different from the one you chose to make it (“Custom” seems from file names).
Each OSD needs its own profile, if you change OSD mode you’ll need to change defdault display profile for that OSD mode. DisplayCAL tray for windows is very helpful for making such changes in a fast way.

I then profiled a custom preset, adjusting the brightness/contrast and RGB (the sRGB and Adobe RGB presets are locked and you cannot adjust them), this was an improvement, but I still can’t seem to get gamut coverage close to the monitor specification

Maye it was not real or maybe there are some issues in the CCSS/CMS you chose. Plot spectral power distribution (SPD), “i” button next to correction if it is a CCSS.
Also instead of looking at % numbers look for dE distance to out of gamut colors, that’s what actually matters (simulation profile ON, use it as display profile OFF), do measurement report and look for OOG colors, and check their dE00.

In comparison my iMac 5K returns as expected results (100% sRGB, 99% P3) and Delta E all below 2 after profile and verification.

DIsplayCAL has a very accurate correction for i1d3 colorimeters and that display. That’s a hint. Plot Lenovo’s CCSS.

Side-by-side the P27u look oversaturated compared to the iMac screen, and too warm.

Make sure that you compare them showing an image, color managed. Profile shows nothing wrong, just under saturation in red-magenta-blu… likely to be caused by correction, but unless you plot it, IDNK.
Once we see that SPD plot we can spot issues or recommend one bundled by default in DisplayCAL (xrite, 1nm resolution) close to its backlight technology

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[Imran Ramzan]

Hi Vincent,

Thank you for taking the time to respond. Apologies I did not understand some of the abbreviations or suggestions…

There is a correction file for the P27u that I applied, and I used the Default testchart and calibration speed set to high.

Which one? Plot it if it’s a CCSS, maybe user who made it did it in the wrong way (non native gamut). CCMX are not really portable between other users and you.

I used Tools>Correction>Check Online, and there was one correction matching my Lenovo, but I understand this maybe wrong. What do you mean by ‘plot it’ please?

I ran a pass on the sRGB and Adobe RGB presets, the results look way off the advertised gamut and accuracy.

How? Your sentence is very ambigous and DisplayCAL can do many things, but you may have chosen the wrong setup.

The default Lenovo display profile

Correction was the online loaded ‘LCD White LED IPS’

Calibration: int. display adj., CIE1931, 6500K, 120cd/m, Black level as measured, Gamma 2.2, speed high

Profiling: Single curve+matrix – black point comp., profile high, default testchart

Ran calibration, loaded the profile, ran verification

Maybe it was not real or maybe there are some issues in the CCSS/CMS you chose. Plot spectral power distribution (SPD), “i” button next to correction if it is a CCSS.
Also instead of looking at % numbers look for dE distance to out of gamut colors, that’s what actually matters (simulation profile ON, use it as display profile OFF), do measurement report and look for OOG colors, and check their dE00.

Sorry what do you mean by ‘simulation profile ON, use it as display profile OFF’?

I’m unsure what kind of panel is in the P27u Display Specifications lists it as a W-LED…

Thank you for taking the time to respond, apologies for my lack of understanding.

[Vincent]

I used Tools>Correction>Check Online, and there was one correction matching my Lenovo, but I understand this maybe wrong. What do you mean by ‘plot it’ please?

Choose your correction, click “i” and it plots on screen. Capture it.

Correction was the online loaded ‘LCD White LED IPS’

This is a wrong choice. That correction is for sRGB displays. There are WLED widegamut variants like WLED PFS, but manufactures or PR dept forget to add “surname” to backlight technology. So 100% sure it is NOT a common White LED.

Sorry what do you mean by ‘simulation profile ON, use it as display profile OFF’?

Verification tab, those settings. ON/OFF like a switch.

All OFF= verify if display matches its asociated profile in OS
Simulation on, use that one as display proflle = verify if display withot GPU calibration matches some colorspace
Simulation on, use as display profile off = verify if under some color managed app, display can show that colospace

[Imran Ramzan]

Choose your correction, click “i” and it plots on screen. Capture it.

‘Lenovo LCD White LED IPS’ settings and plot on left, LCD PFS Phosphor WLED IPS plot on right  as you mentioned this maybe the setting to use?

Verification tab, those settings. ON/OFF like a switch.

All OFF= verify if display matches its asociated profile in OS
Simulation on, use that one as display proflle = verify if display withot GPU calibration matches some colorspace
Simulation on, use as display profile off = verify if under some color managed app, display can show that colospace

Thank you for the clarification

[Vincent]

Looks like a weird/gamut limited GB-LED, and it’s 3 3nm so the kind of information wiped out in 10nm CCSS should be there.

Try bundled (http://displaycal.net/i1d3) GB-r LED / RG Phosphor correction and check if measured RED 255 moves to more saturated coordinates than what your current profile shows. Also you can use “i” to see that it looks like some “limited” version of a GB-LED.

• This reply was modified 3 years, 11 months ago by Vincent.

[Imran Ramzan]

Try bundled (http://displaycal.net/i1d3) GB-r LED / RG Phosphor correction and check if measured RED 255 moves to more saturated coordinates than what your current profile shows.

Measured red looks about the same, ΔE 4.78, if I am looking at the correct info?

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[Vincent]

You are verifiying a profile against display…. and they do not match:
Display is to bad to be described by a simple matrix profile (weird, extremely low quality) or your are verifiying an profile in an OSD mode not suited for it, or you change something in OSD bertween profiling and verification.

Anyway it last profile is OK red seems too undersaturated for manufacturer’s claim.
IMHO avoid ALL AdobeRGB displays not Eizo or NEC, waste of money and time all those LG, Lenovos, Dell, Benq…

But I would say that there is some user error… profile cannot match the display that was measured to make such profile… weird. Maybe you changed something in OSD setup (some “color enhancement” set ON), or in Displaycal operation… IDNK what you did.
But since you use a limited OS like macOS so if you use a more accurate profile type (XYZLUT matrix) some errors may arise. You may try: medium speed, big enough amount of profiling patches for XYZLUTprofile (400+) and check if that new profile fits display behavior. Adobe  suite may render colors properly with that one but all other apps relying in Apple color engine may show artifacts, that includes desktop & UI

[Imran Ramzan]

You are verifiying a profile against display…. and they do not match:
Display is to bad to be described by a simple matrix profile (weird, extremely low quality) or your are verifiying an profile in an OSD mode not suited for it, or you change something in OSD bertween profiling and verification.

This monitor does not have many OSD options, I have disabled auto-contrast, and overdrive is set to normal. There lots of presets and ‘scenario’ modes, but I stuck with using a ‘Custom1’ setting, because it allows full control of the brightness, contrast and RGB.

Anyway it last profile is OK red seems too undersaturated for manufacturer’s claim.
IMHO avoid ALL AdobeRGB displays not Eizo or NEC, waste of money and time all those LG, Lenovos, Dell, Benq…

I’d love to be able to afford an Eizo/NEC but they range from 3 to 8 times the cost. I know ‘you get what you pay for’, I was just hoping to get something half-way decent…

But I would say that there is some user error… profile cannot match the display that was measured to make such profile… weird. Maybe you changed something in OSD setup (some “color enhancement” set ON), or in Displaycal operation… IDNK what you did.

I’m pretty certain OSD wise I have not enabled any settings that dynamically change colour/contrast

But since you use a limited OS like macOS so if you use a more accurate profile type (XYZLUT matrix) some errors may arise. You may try: medium speed, big enough amount of profiling patches for XYZLUTprofile (400+) and check if that new profile fits display behavior. Adobe  suite may render colors properly with that one but all other apps relying in Apple color engine may show artifacts, that includes desktop & UI

So I tried your suggestion of medium, XYZ+LUT, auto-optimise adjusted to 425 testcharts and the results look much better. For my understanding: Mac OS may not fully support XYZ+LUT, but if I mainly use colour-managed apps (in this case Adobe Creative Suite) then I will benefit, but may see some weird artefacts with OS icons and elements, correct?

Thank you for all your help so far Vincent it is very much appreciated!

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[Vincent]

 

So I tried your suggestion of medium, XYZ+LUT, auto-optimise adjusted to 425 testcharts and the results look much better. For my understanding: Mac OS may not fully support XYZ+LUT, but if I mainly use colour-managed apps (in this case Adobe Creative Suite) then I will benefit, but may see some weird artefacts with OS icons and elements, correct?

Thank you for all your help so far Vincent it is very much appreciated!

Now display & profile match. That’s because these table/lut profiles map like nodes (3D) in a cube how display actually behaves. The more nodes the more accurate you describe it. Now LR/PS/GIMP can take that info anf if color is inside display colorspace transform “image”‘s RGB number to some other display’s RGB number and whie those RGB numbers are likely to be different they represent the same color coordinates (en each colorspace, image 1st, display 2nd)

If you want to see the kind of AdoberGB colors that fall outside your display just verify selecting AdoberGb simulation profile but ***do not*** select it as display profile (that 2nd check box must remain unchecked, just “use simulation profile”, 1st one). Same for sRGB, P3, etc. That test checks display profile in color managed apps, its limits.

[Miker]

Hi Ramzan !

I just purchase a Lenovo P32u-10.
Do you notice like me a banding with a black and white image test gradient after calibration?
Try to set original color profile from Lenovo then your profile calibration to see differences.

[Author]

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