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Thanks again. I think I am starting to understand what you are saying. Let me run some new tests and get back to you shortly.
scott
Hi Vincent,
I followed your instructions (as best as I could understand) and here are the results. I have attached the original test “default profile” against the factory profile “LGULTRAFINE” that comes with the mac and then I calibrated and created a profile “LG_5K_P3” and included a verification test for that.
Visually when using the factory profile colors are very rich and blacks are deep. After calibration – blacks are slightly lifted and images look a little less vivid.
Is this ok? Does the monitor seem ok from test results or should I return it?
Thanks again.
All of them seem wrong. Bad grey. Move calibration speed to low. Also attach full HTML not PDF, otherwise I cannot see % of unique grey levels lost when correcting white & grey (and that is non correctable).
Red and green desaturation is caused by color managent AND factory profile not matching actual display behavior. Factory profile says 255 green is less saturated than actual value.
Hi Vincent. Here you go. I re-calibrated at a higher quality setting. The profile created still lifts the blacks compared to the “default profile” on the computer. Doesnt look as rich and vivid but maybe it’s not supposed to. I dunno.
Ihave attached screen shots of all my settings and the report. When I get the warning notice about single curve and matrix I selected “yes”
Let me know.
Thanks!
The profile created still lifts the blacks compared to the “default profile” on the computer.
Now it seems ok.
Profile & calibration lift black because of two facts:
(calibration)
-Uncalibrated display’s grey is NOT neutral. It has “color”/”tint”. In order to make grey neutral you need to raise or lower one or two channel values at certain grey until it measures “grey” (no color, or the same color as desired white). This task has constraints becuse there is an upper & lower limit (255 & 0) and you do not want all top greys be equal or bottom blacks to be equal (you do not want clipping)(profile)
-your OS is extremely limited regarding its color management engine used in desktop. It can only work with idealized profiles, not with actual display behavior. Apple’s fault.
Profile (idealized single curve + BPC) says for example that grey 26 should have relative brightness to its white of L*=5.71… but calibrated display has L*=6.39 for that grey.
A color management engine without Apple’s bugs could take as input a ICC profile that describes calibrated display in an accurate way (RGB 26 => L*=6.39) … although very close to black it should apply some kind of BPC or deal with clipping caused by finite contrast.These are non correctable with your actual HW & OS.
Hi Vincent. Thanks so much for this explanation. I think I am starting to understand.
so if my monitor was more accurate out of the box in the greys – I wouldn’t get this lifting of the blacks (as it wouldn’t have to adjust RGB values correct?)
I am running Mac OS Mojave. Is this a Mac thing regardless of operating system or any idea if newer OS handles color management better?
finally – any thoughts on the Dell U2720Q?
wondering if I should return the LG 5k. I love the way it looks with the factory/ uncalibrated profile – rich and vivid – but I will be using it to edit photos on, so should use it calibrated (flatter look) as well as just generally enjoying a larger screen for desktop/internet etc
Hi Vincent. Thanks so much for this explanation. I think I am starting to understand.
so if my monitor was more accurate out of the box in the greys – I wouldn’t get this lifting of the blacks (as it wouldn’t have to adjust RGB values correct?)
No, or yes. Grey calibration is for white, neutral grey AND gamma. ArgyllCMS tries to preserve a minimum of brightness separation between greys near black. Some lift is unavoidable in low contrast displays like yours (or any other 1000-1500:1 IPS).
I am running Mac OS Mojave. Is this a Mac thing regardless of operating system or any idea if newer OS handles color management better?
It’s a MacOs issue. Other OSes do not have color management on desktop. All oversaturated, RGB values outputed ditecty to display, hence oversaturated & not accurate color if content was meant to be sRGB. But APPs desgned for that OS can be and are color manages so withing those apps colors are accurate: Adobe suite, Firefox, some other browsers, Resolve, madVR, some image viewers…
For these reason displays have sRGB mode.. or HW calibration with gamut emulation.
finally – any thoughts on the Dell U2720Q?
IDNK. Check reviews online that make uniformity reports in the way displaycal does (delta C) and with accurate devices (not spyders)
wondering if I should return the LG 5k. I love the way it looks with the factory/ uncalibrated profile – rich and vivid – but I will be using it to edit photos on, so should use it calibrated (flatter look) as well as just generally enjoying a larger screen for desktop/internet etc
If uniformity is OK and since it seems you do not loose too much levels because whitepoint correctionto D65 in GPU (you keep ~94% which is good) and if your GPU does not cause banding because GPU LUT calibration… looks like it behaves like a good P3 IPS display.
If you wanted to see printable AdobeRGB colors or want D50 white all these apple like displays is not the way to go. If you do not need this, yours seems OK.
That monitor has some advanced color management options.
Make sure to turn off all the post processing stuff, like black leveler, contrast enhancer, things like that.
You want it to be in the default color space, which is either adobe or p3, I can’t tell, which ever one measures the higher total color volume is the one you want to pick.
You need to adjust the RGB gains on that interactive menu so you don’t lose contrast due to the software curve modification.
You can also adjust the rgb cutoff/offset <which> impact the middle of the rgb balance. usually it impacts between 30% and 50% of the grey slides.
Set the gamma to default 2.2 in the monitor, but also try 2.1, 2.3, 2.4 and see if they track more closely to the 2.2 that we’re calibrating to. you don’t need to run the entire calibration, just use the greybalance test chart , and do quick runs on those gamma settings.
Make sure the Monitor is warmed up for 1 hour before you do anything at all, such as these settings, after calibration DO NOT let it go to sleep or turn off before you check measurements, otherwise it won’t be accurate, and the tone curve will not reflect the stable state.
