Brightness Chart – Measuring Brightness with profile possible?

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This topic contains 5 replies, has 2 voices, and was last updated by  Florian Höch (@fhoech) 4 weeks, 1 day ago.

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  • #19378

    Daniel1 (@daniel1)
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    Hello,

    i just calibrated and profiled my new Monitor and i wanted to create a Brightness Chart like this:

    Brightness Setting 0,5,10,…,95,100   with corresponding cd/m² measurement.

    I used the interactive calibration to get live cd/m² readings and adjusted the Brightness of the Monitor. The problem is that it doesn’t use my profile and it is a bit brighter.

    I measured at 140 cd/m² without profile and 128 cd/m² with profile (extracted from a Measurement Report with profile). So can i just assume that all the brightness readings are like -8,5% like this 140->128 ?

    Unfortunately Displaycal doesn’t provide a mode to make a Brightness chart or at least i don’t know how.

    Monitor: Philips 326M6

    Brightness Range from 74 cd/m² to 528 cd/m² (measurement without profile)

    #19392

    Florian Höch (@fhoech)
    Administrator
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    Hi,

    I used the interactive calibration to get live cd/m² readings and adjusted the Brightness of the Monitor. The problem is that it doesn’t use my profile

    Interactive display adjustment is always done without calibration in place.

    I measured at 140 cd/m² without profile and 128 cd/m² with profile (extracted from a Measurement Report with profile). So can i just assume that all the brightness readings are like -8,5% like this 140->128 ?

    No, because it depends on whether or not the calibration alters the whitepoint or not.

    Brightness Setting 0,5,10,…,95,100 with corresponding cd/m² measurement.

    Measure a custom testchart with calibration in place (disable interactive adjustment on calibration tab and set tone curve to “As measured”).

    #19608

    Daniel1 (@daniel1)
    Participant
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    No, because it depends on whether or not the calibration alters the whitepoint or not.

    Yes it does alter the whitepoint. According to a review of the monitor by prad.de the device is better left in the “Color 6500K” mode, because in the custom “Color User” mode with adjustable RGB sliders the colors and greytones are all over the place which i could confirm with my own measurement. So i followed their advice and calibrated using the “Color 6500K” mode where the colors are really accurate but only the whitepoint is not very accurate.

    So i can assume that with applied profile (with altered whitepoint) the brightness is rougly -8,5% over the entire brightness range right?

    Measure a custom testchart with calibration in place (disable interactive adjustment on calibration tab and set tone curve to “As measured”).

    You mean a custom testchart with only 1 full white test color, and repeat the measurement after each brightness state i want to measure?

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    #19625

    Florian Höch (@fhoech)
    Administrator
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    So i can assume that with applied profile (with altered whitepoint) the brightness is rougly -8,5% over the entire brightness range right?

    If that is what you have measured with the specific calibration in place.

    You mean a custom testchart with only 1 full white test color, and repeat the measurement after each brightness state i want to measure?

    No, put all the brightness levels in the testchart, i.e. from 0% to 100% (RGB), say in 5% to 10% increments (the grayscale verification chart uses 2.5% increments in case you want to use that).

    #19626

    Daniel1 (@daniel1)
    Participant
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    No, put all the brightness levels in the testchart, i.e. from 0% to 100% (RGB), say in 5% to 10% increments (the grayscale verification chart uses 2.5% increments in case you want to use that).

    I think we are not talking about the same thing. I want to measure the brightness on full white for each Monitor-OSD setting 0,5,10,…95,100.

    If i don’t change the brightness via the OSD it always stays the same. Since the behaviour is not linear and every monitor has their own “curve” i wanted to measure it.

    Here are my notes without calibration in place via the interactive calibration (everything on full white):

    Brightness-OSD Setting          Brightness in cd/m²

    0  74
    6 99
    11 118
    14 130
    17 140
    25 167
    30 192
    35 208
    40 226
    45 245
    50 265
    55 284
    60 301
    65 320
    70 336
    75 352
    80 372
    85 391
    90 407
    95 470
    100 528

    #19697

    Florian Höch (@fhoech)
    Administrator
    • Offline

    In that case you can either use Argyll’s spotread on the command line or the “Untethered” display (in the latter case, you have to convert D50 L*a*b* back to XYZ).

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