Grayscale color banding after calibrating

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  • #26132

    Anonymous
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    Hello,

    My problem is pretty much as simple as the title. I’m using a x-rite i1 display studio to calibrate my surface laptop 3 13.5″ display. I’m calibrating my display for the occasional movie/general use. It comes factory calibrated but the white point and gamma are slightly off of D65 and 2.2 (I’ve tried 2.4 as well). I’ve played around with a ton of settings but can’t seem to fix the issue. Even leaving the laptop preset in displaycal at default settings with 2.2 gamma and native white point causes noticeable color banding. The default sRGB color profile that comes with the laptop has faint pink and greenish banding, but switching to the displaycal profile after calibrating shows very prominent pink and yellow grayscale banding. The difference is apparent in both full-quality lossless blu-rays in all video players and on a simple grayscale gradient from google images. There isn’t a lot of documentation on this display so I’m a little lost. I assume it’s a hardware limitation, though. It’s an 8-bit panel. Maybe my calibration instrument isn’t as precise as the one they use for factory calibration? A windows color management issue? Low-quality panel? I dunno.

    Sorry for the word vomit but any explanation would be helpful.

    Thanks.

    i1Display Studio on Amazon  
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    #26142

    Vincent
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    It’s a GPU limitation. 8bit LUT and no dithering. An 8bit panel can be calibrated without issue as long as correction is done at high bitdepth and then dithered to 8bit.
    AFAIK all intel iGPUs suffer this limitation. Some desktop nvidias sometimes have the same issue. Desktop AMDs as long as you use AMD propietary driver and DisplayCAL GPU calibration loader have no such issues even over 8bit DVI connection. The key is “dithering”.

    If you make a “Profile only” profile, without calibration at native white, Lightroom (develop module) or CaptureOne should have no banding since their output is dithered and with “no calibration” there should be no bands.
    If your GPU+CPU has enough power you may try a video player with dithering like madVR. Maybe MPV can do the same. The previous “profile only, no calibration” ICC will be used as source for both.

    These solutions won’t fix your uncalibrated grey tints on desktoo or other applications, or calibration induced banding. AFAIK there is no solution for your laptop in those scenarios.

    #26143

    Anonymous
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    Ahh that makes sense. madVR error diffusion dithering reduces the banding but it doesn’t go away. I had tried that before.  The iris plus iGPU is pretty powerful so it runs madVR well. Thank you for the response.

    #26219

    Anonymous
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    I figured it out!

    The Surface laptop 3 13.5″ display uses white LEDs for backlighting so I had to apply that spectral correction manually to displaycal. Auto didn’t apply any correction. Everything is perfect now. No weird banding or tinting. I discovered this by using the i1 profiler software included with x-rite’s products. Their software automatically applied a white LED correction before calibrating.

    Hopefully someone can find this information useful!

    #26220

    Vincent
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    I figured it out!

    The Surface laptop 3 13.5″ display uses white LEDs for backlighting so I had to apply that spectral correction manually to displaycal. Auto didn’t apply any correction. Everything is perfect now. No weird banding or tinting. I discovered this by using the i1 profiler software included with x-rite’s products. Their software automatically applied a white LED correction before calibrating.

    Hopefully someone can find this information useful!

    This is not the solution for your issues, 100% sure.

    Spectral correction applies THE SAME 3×3 matrix multiplication (once computer from CCSS and colorimeter firmware) for each measured raw RGB value from colorimeter. Not applying proper correction imposes the same correction for all greys, all of them. Applying the proper one does the same, but with a different matrix values, but the same matrix to all measured colors.

    By applying proper correction you get a whitepoint that should be visually more OK. That menas that if your Surface native uncorrected white point is closer to calibration target (like D65) it has to correct “less”so you loose less unique grey levels for white. If factory grey calibration is OK, overall resulting calibration will differ very litle from an input=output calibration tables.
    Banding induced calibration issues remains there, just happens that for that particular screen  and calibration target resulting calibration correction is small/mild, so they are less noticeable.
    Aim for another whitepoint target, like D50,  using GPU LUTs since you do not have RGB gains on screen and you will suffer the same issues you reported previously.

    Banding issues are HW & GPU driver related, or LUT loader related (but DisplayCAL does it OK so this does not apply).

    • This reply was modified 4 months, 4 weeks ago by Vincent.
    #26225

    Anonymous
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    D50 at 2.2 has no banding issues :/

    Nothing compared to what was going on before. It’s not a completely smooth gradient but the default profile wasn’t either. The D50 and default profile are virtually identical in the amount of banding present.

    #26230

    Vincent
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    D50 at 2.2 has no banding issues :/

    Nothing compared to what was going on before. It’s not a completely smooth gradient but the default profile wasn’t either. The D50 and default profile are virtually identical in the amount of banding present.

    Then you changed something else, not just correction. Like using windows calibration loader instead of DisplayCAL, GPU driver update or such things.

    Changing spectral correction just changes 3×3 matrix applied to raw RGB values from colorimeter to get XYZ coordinates, the same multiplication for ALL colors. If greys were “spread” in a*b* planes they remain spread.
    Correction cannot solve your issues, it solves whitepoint and 255 R,G,B XYZ coordinates.

    • This reply was modified 4 months, 4 weeks ago by Vincent.
    #26232

    Anonymous
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    Hmmm something does seem to have changed. The banding is gone even without the correction. Anyway, thanks for the information.

    #28011

    Anonymous
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    Ok I fixed the issue 100%. Disabled surface color profile driver in device manager + 3dlut calibration in madvr and it’s perfect. No color tinted greys or banding in video (and on windows desktop). The default profiles have noticeable grayscale color tint and banding now that I’ve seen the display without them enabled. Microsoft’s implementation of factory calibrated color profiles on surface devices is poor I guess. Feel free to explain why this worked.

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