What does “Measured vs. assumed target whitepoint ΔE*00 ” mean?

Home Forums Help and Support What does “Measured vs. assumed target whitepoint ΔE*00 ” mean?

Viewing 6 posts - 1 through 6 (of 6 total)
  • Author
    Posts
  • #38941

    mike12
    Participant
    • Offline

    Hello!

    I have calibrated my monitor using the i1 display plus with gamma 2.2 and sRGB. I have looked at before and after reports and this value seems to have increased instead of decrease, said value is “Measured vs. assumed target whitepoint ΔE*00”. I am not sure what it is. Can someone explain? Thank you.

    Also, how does one calibrate according to the brightness of the room?

    #38944

    Vincent
    Participant
    • Offline

    Hello!

    I have calibrated my monitor using the i1 display plus with gamma 2.2 and sRGB. I have looked at before and after reports and this value seems to have increased instead of decrease, said value is “Measured vs. assumed target whitepoint ΔE*00”. I am not sure what it is. Can someone explain? Thank you.

    Whiteness test.
    Google L*a*b*.

    CCT in kelvin is somehow “b*”, yellow blue.
    If we assume that you aimed to daylight locus (google daylight locus), you want a white that “is white” (regardless if it is yellow or blue), not pink not green. This is a* axis.

    “assumed target whitepoint” finds closest daylight locus (100K increment) to measured white and calculates the deviation from whiteness.

    If you aimed to a visual match to another white or to some paper color or light booth you are not aiming to daylight locus and you can ignore this test.

    If you used a vendor propietary HW calibration (Dell, Bem, Eizo…) it may mean:
    -using different set of  (maybe wrong) colorimeter corrections than DisplayCAL
    -HW calibration solution not working as expected (even we assume correct colorimeter corrections)

    If you used a laptop it usually meas that you did not aim to any daylight white, user’s choice. If that laptop is an old macbook (non XDR) maybe you are using this setup because macOS limitations with complex profiles and VCGT. Read macbook threads.

    It can also be your misconfiguration, like measuring with a different correction (or none) than the one used to create iCC.

    Also, how does one calibrate according to the brightness of the room?

    Set white level to native and in popup window when you fix RGB gains lower brightness till you are confortable… or till you get a match to a light booth.

    #38956

    mike12
    Participant
    • Offline

    Understood, thanks alot! I have had a new problem however, hoping you could help.

    I am trying to calibrate my Q60A using a 2.1 HDMI to my laptop, at first it refused to recognize there was a second display connected and after it did not recognize it was 4k and kept it as HD, is that normal? Also how does one install an ICC profile on the TV since calibrating a monitor, it is installed on the graphics card of the computer and thus can be used as long as they are connected to each other. I do not understand how it works when it comes to TVs.

    Help is very appreciated! Thanks alot!

    #38961

    Vincent
    Participant
    • Offline

    Extend desktop (do not clone) then proceed like with any other display as long as it’s connected to a computer… but since it’s a TV watch for HDMI range issues. GPU and display should work on same range.

    If you mean how to calibrate a TV to use as TV without computer, use “HCFR”, get latest from arthur lieberman on AVSForum. Same warning on HDMI levels (video range vs full range) when connecting to laptop or to apattern genertor.

    #38962

    mike12
    Participant
    • Offline

    I’m not sure i understand HDMI levels but Thanks for the tips! I’ll download HCFR and try using it.  I have a question about gamut volume. I have been calibrating my laptop and have gotten a volume of about 50% but have also a coverage very close to that, when verifying it is all far off target. Could it also be due to my configuration or is it that the display does not have enough gamut volume or what not. I messed around and tried a few settings but have gotten almost the same outcome everytime. What could be the problem? Thanks!

    #38995

    Vincent
    Participant
    • Offline

    I’m not sure i understand HDMI levels but Thanks for the tips!

    In video/TV world signal is 16-235, so black is 16 and white is 235. The other values are used for other things.
    Computer display usually work on 0-255 range, even if video content is 16-235, just happens that video playyer apps scales it to 0-255 and even performs color management if needed.

    I’ll download HCFR and try using it.  I have a question about gamut volume. I have been calibrating my laptop and have gotten a volume of about 50% but have also a coverage very close to that, when verifying it is all far off target. Could it also be due to my configuration or is it that the display does not have enough gamut volume or what not. I messed around and tried a few settings but have gotten almost the same outcome everytime. What could be the problem? Thanks!

    Volume = “cubic meters” how big it is compared to something.
    Coverage = “intersection” how much of it overlaps with something (like sRGB).

    50% sRGB coverage is typical for low end TN/IPS laptop displays for office use. It means that screen is as bad as it looks.
    Most color mabanged apps will aim for colorimetric intent (clipping colors out of gamut, OOG) although if some software could use perceptual intent you may avoid color management cliping  of OOG at the expense of overall color deformation .

    Since Office or developement tools are not color managed, aim for a simple curve+matrix profile to correct grey and maybe white(at the expense of contrast)… that’s all you can do.

Viewing 6 posts - 1 through 6 (of 6 total)

You must be logged in to reply to this topic.

Log in or Register

Display Calibration and Characterization powered by ArgyllCMS