One notebook plus two external screens. How to get identical colors?

[Arthur Hoornweg]

Hello all,

I have a new Dell Precision 5540 laprop which has a high gamut 4K lcd screen.
Plus I have two external LG  LCD’s that are “just” srgb.

What I want to achieve is that the three screens have near-identical color rendering for NON-color management-aware applications, so that when I drag a picture or application from one screen to the other the colors stay the same.  I just want all screens to behave like the largest common denominator of the three and conform to srgb as good as possible.

The Dell came with a “Premiercolor” app that has a few presets to limit the color gamut of the builtin screen to sRGB.  A nice idea, but terribly implemented : it produces such hideous banding in dark parts of the image that it really distracts when watching videos on Netflix.  A real eye sore.  So I have removed Premiercolor and reset the colors to default in the Intel Graphics command center. This fixes the banding issue but still leaves me with the supersaturated candy colors.

I tried to calibrate the notebook screen to srgb with Displaycal  (I have a Spyder 3 sensor)  but still the outcome is oversaturated.

Can anyone please point me to a “how to” guide on how to achieve this?  I am not a color management expert, nor do I want to be one.  I’d really hate to have to install Premiercolor again.

[Vincent]

What I want to achieve is that the three screens have near-identical color rendering for NON-color management-aware applications, so that when I drag a picture or application from one screen to the other the colors stay the same.  I just want all screens to behave like the largest common denominator of the three and conform to srgb as good as possible.

The Dell came with a “Premiercolor” app that has a few presets to limit the color gamut of the builtin screen to sRGB.  A nice idea, but terribly implemented : it produces such hideous banding in dark parts of the image that it really distracts when watching videos on Netflix.

Then you can’t. You can just fix white point and grey.

For gamut emulation to that g.c.d. you need color management (and contents constrained to that colorspace) or some kind of HW calibration in the monitor with bigger gamut. Since DPC does not work as intended in your laptop, there is no solution.

IDNK which app you use for Netflix, but some video players are color managed like teh ones that support madVR.
The funny thing is that if I had downloaded … let say The Witcher from an “illegal source” I would play it as Rec709 g2.4 in a widegamut display without using HW calibration, just madVR software LUT3D support… and some guy who pays its subscription using some non color managed app… they can’t.
Check if there is some kind of color management in the app you use, if not, check if you can consume Netflix videos from some player with madVR support. If not complain to Netflix, you pay for it. P3 for gamming/multimedia in Windows enviroments are more common these days.

PS: Also Spyder3 is unsuitable for measuring modern LED backlights.

[Arthur Hoornweg]

Hmmm, then am I mis-understanding the whole purpose of calibration?

I always thought that the difference between calibration and profiling was that profiling determines the characteristics of the screen and stores it in a icc file (so that icc-aware programs can perform some wizardry to produce “correct” colors on screen),  whereas calibration would first profile the screen, then compute a bunch of values to be pre-loaded into a color lookup table on the vga card,  which would have the effect of automatically converting “raw” input rgb values into “calibrated” rgb luminosity values?

At least that’s what I would expect and desire. Please correct me if I’m wrong.

[Vincent]

Hmmm, then am I mis-understanding the whole purpose of calibration?

I always thought that the difference between calibration and profiling was that profiling determines the characteristics of the screen and stores it in a icc file (so that icc-aware programs can perform some wizardry to produce “correct” colors on screen),  whereas calibration would first profile the screen, then compute a bunch of values to be pre-loaded into a color lookup table on the vga card,  which would have the effect of automatically converting “raw” input rgb values into “calibrated” rgb luminosity values?

At least that’s what I would expect and desire. Please correct me if I’m wrong.

Yes, it is that way, but video card can only load a lookup table in 1D = grey. At least with a vendor agnostic API used by i1Profiler, Basiccolor Dsplay (no HW cal display), DisplayCAL… etc
Some GPUs have a matrix lut for emulating idealized colorspaces like sRGB but AFAIK there is no vendor agnostic way to load such data. AMD driver call it with the misleading name “color temperature = OFF” (limit native EDID gamut to sRGB), and such gamut emulation is not based on user data but in EDID data.

So if you want gamut emulation (calibration to certain whitepoint, neutral grey and gamut limitation), not just grey, you need to use HW calibration with gamut emulation or color managed apps.
DPC was supposed to provide this at GPU level or with some HW LUT-matrix… but if it is not working, there is nothing you can do but to use color managed apps.

• This reply was modified 4 years, 4 months ago by Vincent.

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