Bad "Black/white" gradient after calibration

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  • #11220

    Kirill Polyanskyy
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    I calibrate 2 monitors Viewsonic VX3211-2K-mhd(main new) and Dell u2410(old) by i1 display pro. On each of them after calibration i have a problem with a “gray” gradient: strips&color strips.

    Viewsonic VX3211-2K-mhd ->

    Before calibrate i measured color temprature(7100) and white level(160cd/m2), then adjust it to “6500” & “120” by monitor menu -> RGB(94-92-89) / brightness-34 / contrast-70 / view mode – standard / Blue light filter – 0 / Black stabilization – 100(I tried different values, but this value was the best for LUT curve).

    Other setting i attach, sory but photos of the monitor is not good. On photo many !!color!! glow effects, but just camera see this effects, in real life my eye see only glow on black !!!without tints!!!.

    Before calibration i see a good smooth BW gradient without color tints, strips etc.

    What I do wrong?

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    #11227

    Vincent
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    There are several causes of that banding.

    1-Color management could cause this. So better to test with a non color managed application. Internet explorer, MS Photos or classical windows image viewer at full screen.
    If you test this in such situation and banding is gone, then it is related to color management. Try simple profiles like single curves + matrix to solve or minimize it.

    2-OS’ LUT loader. If you dont’ use DisplayCAL LUT loader, or even of you use it but you allow OS lut loader to do something, it may cause truncation in LUT content. For example latest versions of MS windows when screen goes to standby and comes back , “night mode” even if you go to night mode and after a while go back to normal, other calibration software like i1Profile and its hardware calibration equivalents (dell, viewsonic…). Whenever these situations happen, LUT contents are truncated and the only way to solve this is a reboot.
    Ensure that your monitor does not go to standby in any situation after a reboot, ensure that DisplayCAL loader is the only active LUT loader in your system. Then test banding in a non color managed app. If it is gone you found what caused it.

    A ICM profile with only 8bit VCGT data may cause this too, but from your screenshots it is not your situation, so ignore this sentence.

    3-Hardware+drivers. Your nvidia titan in particular. Nvidia is know to had problems with lut truncating to 8bit or not enabling dithering at the output of LUT tables.
    Make sure that you enabled more than 8bpc in nvidia control panel and that you are using HDMI or DP connection. If you did not meet this pre requisites,  reboot and test again and check if banding is gone.
    If you didn’t locate the source of your problems in 1st or 2nd test, and >8bpc +HDMI/DP connection did not solve your issues, then it’s very likely to be caused by your nvidia. Solution: Get an AMD GPU or get a monitor with working* hardware calibration… or ask nvidia to fix their drivers and HW, but this last one is not very likely to solve your problems in short term.

    *=there are HW calibration solutions that cannot fix grey tint issues in the same way DisplayCAL does with a high bitdepth LUT with dithering. I mean that they are worse tha DisplayCAL with an appropiate GPU.
    These HW cal solutions take too few measurements to native gamma ramp so some tint in uncalibrated gray scale may not be solved after hardware calibration. DisplayCAL can do a more fine grain work measuring gray scale in tiny steps in order to correct these issues.

    • This reply was modified 2 years, 4 months ago by Vincent. Reason: typo
    #11234

    Kirill Polyanskyy
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    There are several causes of that banding.

    1-Color management could cause this. So better to test with a non color managed application. Internet explorer, MS Photos or classical windows image viewer at full screen.
    If you test this in such situation and banding is gone, then it is related to color management. Try simple profiles like single curves + matrix to solve or minimize it.

    2-OS’ LUT loader. If you dont’ use DisplayCAL LUT loader, or even of you use it but you allow OS lut loader to do something, it may cause truncation in LUT content. For example latest versions of MS windows when screen goes to standby and comes back , “night mode” even if you go to night mode and after a while go back to normal, other calibration software like i1Profile and its hardware calibration equivalents (dell, viewsonic…). Whenever these situations happen, LUT contents are truncated and the only way to solve this is a reboot.
    Ensure that your monitor does not go to standby in any situation after a reboot, ensure that DisplayCAL loader is the only active LUT loader in your system. Then test banding in a non color managed app. If it is gone you found what caused it.

    A ICM profile with only 8bit VCGT data may cause this too, but from your screenshots it is not your situation, so ignore this sentence.

    3-Hardware+drivers. Your nvidia titan in particular. Nvidia is know to had problems with lut truncating to 8bit or not enabling dithering at the output of LUT tables.
    Make sure that you enabled more than 8bpc in nvidia control panel and that you are using HDMI or DP connection. If you did not meet this pre requisites,  reboot and test again and check if banding is gone.
    If you didn’t locate the source of your problems in 1st or 2nd test, and >8bpc +HDMI/DP connection did not solve your issues, then it’s very likely to be caused by your nvidia. Solution: Get an AMD GPU or get a monitor with working* hardware calibration… or ask nvidia to fix their drivers and HW, but this last one is not very likely to solve your problems in short term.

    *=there are HW calibration solutions that cannot fix grey tint issues in the same way DisplayCAL does with a high bitdepth LUT with dithering. I mean that they are worse tha DisplayCAL with an appropiate GPU.
    These HW cal solutions take too few measurements to native gamma ramp so some tint in uncalibrated gray scale may not be solved after hardware calibration. DisplayCAL can do a more fine grain work measuring gray scale in tiny steps in order to correct these issues.

    For “clean test” first of all I install latest driver nvidia with full uninstall previous. Then i unplug my old Dell/hdmi and leave only main Viewsonic/display port. Calibrate at once again with different options on 175 testchart patches: single curves + matrix, XYZ LUT + matrix (white drift level compensation / black level drift compensation / Black point compensation). Install it all one by one (displaycal loader is enable/ bith depth 16)and check gradient in photoshop, browser, standard win 10 viewer – problem with banding not solved. Yesterday i try to increase value of testchart(profiling menu) =>1500 pathes and it hasn’t resulted in success(

    When i use standart windows “linear” profiles like sRGB Color Space Profile.icc or delete(leave color managment empty)  .. gradient is brilliant in all soft but calibrator says that colors are bad((((

    You say that DisplayCAL can do a more fine grain work !!!!measuring gray scale in tiny steps!!! in order to correct these issues. How  i adjust it?  Just increase main testchart or it is adjusted in other place?

    *iprofiler also didn’t fix it

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    #11237

    Vincent
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    First of all, please check that nvidia control panel has >8bpc selected and that you use HDMI/DP connection. Nvidia has trouble with 8bpc or over DVI connections: truncation or no dithering, hence that banding rounding errors.

    You say that DisplayCAL can do a more fine grain work !!!!measuring gray scale in tiny steps!!! in order to correct these issues. How i adjust it? Just increase main testchart or it is adjusted in other place?

    It’s called calibration speed.
    Before profilling DisplayCAL measures in an iterative process grey ramp to compute calibration. Once computed (VCGT data) it applies it, then with monitor calibrated measure for profilling.
    Calibration speed=”Slow” (for example) aims for 4 (I think that they are 4) iterations: 12 meaurements, then 24, then 48, then 96 at 4th iteration. 96 steps gives you a jump of 3/256 RGB values, very fine grained.
    You may try to decrease calibration speed (in calibration tab) from “High” (your screenshot) to “Low”.

    Increasing testchart is not useful for your problem. Same goes if you use “big” XYZLUT profiles. These are related to profiling stage, but you have calibration problems since you say that you see those banding artifacts in non color managed apps.
    Save your time and use simple profiles in your testing.: they won’t affect your test in non color managed apps.

    *iprofiler also didn’t fix it

    It cannot fix it, at least with lastest Win10. Read what I wrote about alternative LUT loaders.
    Using it may truncate LUTs to 8bit untill new reboot and DisplayCAL taskabar app cannot help you even if you use “bitdepth” setting. It is related to something (wrong) introduced in some of the lastest Windows 10 editions that causes truncation when you let OS to load something into graphics card LUT. IDNK what it is.

    ***

    If you tested with these settings (10bpc Displayport connection for example), used DisplayCAL with slow calibration to get 96 measurements  of grey scale in last iteration and after calibration non color managed apps show banding… then it is likely to be caused by your nvidia (or its drivers): get an AMD GPU or buy a monitor with HW cal. Sorry.

    • This reply was modified 2 years, 4 months ago by Vincent. Reason: typo
    #11245

    Kirill Polyanskyy
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    First of all, please check that nvidia control panel has >8bpc selected and that you use HDMI/DP connection. Nvidia has trouble with 8bpc or over DVI connections: truncation or no dithering, hence that banding rounding errors.

    You say that DisplayCAL can do a more fine grain work !!!!measuring gray scale in tiny steps!!! in order to correct these issues. How i adjust it? Just increase main testchart or it is adjusted in other place?

    It’s called calibration speed.
    Before profilling DisplayCAL measures in an iterative process grey ramp to compute calibration. Once computed (VCGT data) it applies it, then with monitor calibrated measure for profilling.
    Calibration speed=”Slow” (for example) aims for 4 (I think that they are 4) iterations: 12 meaurements, then 24, then 48, then 96 at 4th iteration. 96 steps gives you a jump of 3/256 RGB values, very fine grained.
    You may try to decrease calibration speed (in calibration tab) from “High” (your screenshot) to “Low”.

    Increasing testchart is not useful for your problem. Same goes if you use “big” XYZLUT profiles. These are related to profiling stage, but you have calibration problems since you say that you see those banding artifacts in non color managed apps.
    Save your time and use simple profiles in your testing.: they won’t affect your test in non color managed apps.

    *iprofiler also didn’t fix it

    It cannot fix it, at least with lastest Win10. Read what I wrote about alternative LUT loaders.
    Using it may truncate LUTs to 8bit untill new reboot and DisplayCAL taskabar app cannot help you even if you use “bitdepth” setting. It is related to something (wrong) introduced in some of the lastest Windows 10 editions that causes truncation when you let OS to load something into graphics card LUT. IDNK what it is.

    ***

    If you tested with these settings (10bpc Displayport connection for example), used DisplayCAL with slow calibration to get 96 measurements  of grey scale in last iteration and after calibration non color managed apps show banding… then it is likely to be caused by your nvidia (or its drivers): get an AMD GPU or buy a monitor with HW cal. Sorry.

    I check nvidia control panel -> set 10bit/full range color, calibrate in “low” speed, try switch to another gpu nvidia card(no have amd) = problem is the same((. I have to make a choice: good gradient/bad colors or good colors/bad gradient

    Thanks for your participation.

    #25672

    Krzysz
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    Hey, did you solve your problem from 2018? I have exactly the same problem with calibration all 3 monitors (one of them has HW Calibration, but that doesn’t change anything). Thanks.

    #25673

    Vincent
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    Hey, did you solve your problem from 2018? I have exactly the same problem with calibration all 3 monitors (one of them has HW Calibration, but that doesn’t change anything). Thanks.

    -Get an AMD card
    -Get an i1displaypro or i1d3 variant
    -Get DisplayCAL, get a proper spectral correction for your displays’ backlight
    -Configure calibration speed to low, profile type to single curve + matrix + bpc

    or

    -Get a reliable monitor with HW calibration (Eizo, NEC, not a Benq or a Dell with HW cal)

    #25675

    Kirill Polyanskyy
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    Hey, did you solve your problem from 2018? I have exactly the same problem with calibration all 3 monitors (one of them has HW Calibration, but that doesn’t change anything). Thanks.

    No, problem is the same.

    I have come to the conclusion that manually calibrating cheap monitors (no professional) the gradient problem will always be more or less.

    It is better to use the standard profiles (SRGB/ADOBE/) of the monitor itself (if it is a professional Eizo/Nec/maybe VP series Viewsonic… etc) without a problem with gradients and receive a color rendering that is close to reality, but you need to pay a lot of money for all this .

    I am personally used to it, but the next monitor I will get will only be with HW because not all software supports Icc profile (e.g. Blender-cycles/evee, 3d max-octane render,….).

    #25676

    Krzysz
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    I have NEC EA271Q which has hardware calibration and im using i1display Pro. Other monitors are hp2475w (Adobe RGB) and old eizo S1931. They are not professional but no cheap also. It doesnt matter anyway. Gfx is nvidia gtx970.  I get super smooth gradients everywhere the moment i switch to standard icc profile in Windows  (no color management). Otherwise they are jagged and not smooth no matter the monitor nor software( tried displayCAL  and i1 software also)

    As for only doing HW calibration – afaik its not possible cause you have to have icc profile for correct colors.

    #25677

    Vincent
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    I have NEC EA271Q which has hardware calibration and im using i1display Pro.

    Only if you pay it (SV2) and use it. Two requirements

     Gfx is nvidia gtx970.

    =banding, or high chances of banding if you use GPU LUTs.

     I get super smooth gradients everywhere the moment i switch to standard icc profile in Windows  (no color management). Otherwise they are jagged and not smooth no matter the monitor nor software( tried displayCAL  and i1 software also)

    Where?

    Do they happen in MS paint? YES => caused by calibration
    Do they happen only in color managed editors but not in MS paint? YES => caused by profile type. Use profile type as instructed.
    Also some color managed editor have truncation errors, banding there is caused by app, not by profile. Use editors with high bitdepth processing and dithered outputs like LR or Capture One.

    As for only doing HW calibration – afaik its not possible cause you have to have icc profile for correct colors.

    Explained above

    • This reply was modified 1 week, 2 days ago by Vincent.
    • This reply was modified 1 week, 2 days ago by Vincent.
    #25687

    Krzysz
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    Problem solved with SV2 – didn’t know that’s the only way to use hardware calibration on this model. After true HW calibration there is no banding. So  when you want to profile displays with no HW calibration, you have to choose – better colours or smooth gradient. On real photos this gradient isn’t to be seen on anyways i guess, am i right? Thanks!

    #25688

    Vincent
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    So  when you want to profile displays with no HW calibration, you have to choose – better colours or smooth gradient. On real photos this gradient isn’t to be seen on anyways i guess, am i right? Thanks!

    Not really.

    If you just want to profile without calibrating grey ramp in GPU the banding is caused by application itself and its lack of precision when outputing content to screen. Some apps do better than others. LR or CaptureOne “should” have no banding with all profile types. Choosing an idealized profile like single curves +matrix + bpc minimizes to some extent this kind of rounding errors caused by application.
    This applies too to HW calibration and the profile made after it.

    If you want to calibrate grey ramp using GPU and profile your now gpu-calibrated display, then you need a GPU that causes no banding when loading corrections to its LUTs because it has high bitdepth luts and dithering.
    AMD is the safest choice here since 15 years ago, it just works on all kinds of outputs (DVI,HDMI, DP, 8bit-10bit, does not matter) as long as you use DisplayCAL LUT Loader (tray icon) or equivalent precision 3rd party app… although some users made their gamer nvidias work with dithered outputs “in some situations” using the same DisplayCAL LUT loader.

    • This reply was modified 1 week, 1 day ago by Vincent.
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