Measure Ambient Light ?

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  • #25883

    Christopher
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    I read the documentation but I’m stuck on how do I measure the ambient light for the room using the calibrator; although what is the solution considering ambient light can change alot during the day how does this tie together ?

    #25909

    Vincent
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    Go to console, have ArgyllCMS bin folder in PATH, then “spotread -a”.

    Do not use ambient light for calibration even if it remains constant. It may work for not color managed video apps but color management will undo it for the other apps because it is meant to do it.

    • This reply was modified 4 months, 2 weeks ago by Vincent.
    #25920

    Christopher
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    What can finding the ambient lighting of the room help ?

    #25922

    Vincent
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    In non color managed enviroments (= ICC profile is ignored and display is believed to behave like some “reference”) it may “deform” display gamma so “it looks like something” under those conditions even if when measured (ICC profile) it does not behave like that “something target”.
    Profile stores “actual behavior” so ambient light compensation is useless and more a problem than a solution if apps can read that profile

    #25927

    Christopher
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    It sounds as if measuring the ambient light which my calibration can do, is useless.

    #25930

    Vincent
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    It sounds as if measuring the ambient light which my calibration can do, is useless.

    It is… in color managed enviroments. I’ve explained it previously.

    #25934

    Christopher
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    What isn’t considered a color managed environment, multiple monitors that are not calibrated ?

    #25937

    Vincent
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    What isn’t considered a color managed environment, multiple monitors that are not calibrated ?

    A few examples of non color managed enviroment under MS Windows
    -MS windows, app menus, buttons, wallpaper
    -MS Paint, MS photos, MS Office (at least 2016 and lower versions)
    -games
    -most video players like VLC
    -most video editors like VEGAS (latest premiere is color managed and Davinci Resolve can work color managed too)
    -mostly …everything!

    A few examples of color managed enviroment under windows, if we assume that you have assigned in OS a profile to your display that actually describes its behavior
    -Adobe suite
    -Capture One
    -GIMP
    -Partially and possibly with some user extra configuration newer internet browsers like new Edge, Firefox
    -Video players that support madVR and its LUT3D like Media player classic and such
    -partially old windows image viewer when not in full screen

    • This reply was modified 4 months, 2 weeks ago by Vincent.
    #25954

    Christopher
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    When DisplayCAL has created the ICC profile, I should apply that profile to Windows so that buttons, menus etc are calibrated; or should I color manage buttons and menus separately ?

    Therefore DisplayCAL created the ICC profile that only applies to programs which use a color managed environment ?

    #25956

    Vincent
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    When DisplayCAL has created the ICC profile, I should apply that profile to Windows so that buttons, menus etc are calibrated; or should I color manage buttons and menus separately ?

    They won’t be calibrated at all, with exception of gamma & grey. Windows desktop is not color managed.

    Therefore DisplayCAL created the ICC profile that only applies to programs which use a color managed environment ?

    with exception of gamma & grey (including white as a grey). That’s what is stored in VCGT tag in ICC file and loads into graphics card LUT aka “GPU calibration” aka “grey calibration”.

    #25959

    Christopher
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    They won’t be calibrated at all, with exception of gamma & grey. Windows desktop is not color managed.

    Once DisplayCAL has done the calibration and created the ICC profile, it seems the only answer to fix the over saturated Windows menus, buttons etc; is to re-adjust the displays RGB values to ones liking.

    RGB is stores in a ICC profile, but not gamma and gray, why not ?

    #25960

    Vincent
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    They won’t be calibrated at all, with exception of gamma & grey. Windows desktop is not color managed.

    Once DisplayCAL has done the calibration and created the ICC profile, it seems the only answer to fix the over saturated Windows menus, buttons etc; is to re-adjust the displays RGB values to ones liking.

    It seems that you do not get it:

    YOU CAN’T, unless monitor has some sRGB mode, or HW calibration to get it close to sRGB, or some per channel saturation / 6-axis.

    “RGB” controls, usaly named RGB “gains” just fixes white point and nothing else.

    Also if you modify sometjing in OSD after profile is made… profile becames broken = “no longer valid”

    RGB is stores in a ICC profile, but not gamma and gray, why not ?

    ICC profile does not store such thing. You get it all wrong.

    It will be better that unless to go back to start and learn first basic concepts of color management, return your current nmonitor and get one thta is just RGB an nothing more. Widegamuts are not for you, or for your task.

    #25963

    Vincent
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    RGB is stores in a ICC profile, but not gamma and gray, why not ?

    ICC profile does not store such thing. You get it all wrong.

    It will be better that unless to go back to start and learn first basic concepts of color management, return your current nmonitor and get one thta is just RGB an nothing more. Widegamuts are not for you, or for your task.

    Maybe I found the source of your misunderstanding.

    ICC profile, since is just display description, not a calibration AS A GENERAL RULE, stores in a simplified way “color coordinates” for R 255, for G255 and for B 255, for the primaries. It also stores coordinates of white (in several ways out of scope of this reply) and final “gamma” value.
    Please remind what I wrote… these “RGB coordinate” stuff is NOT configuration values. These are just actual values of what you get and the end of calibration.
    So a profile as a general rule just stores “RGB triangle” of coordinates, white and resulting gamma. A DESCRIPTION of how display behaves, nothing more.
    Then optionally it can store grey calibration (and white is a grey) in VCGT tag. That’s DisplayCAL or i1Profiler grey calibration stored inside ICC profile.

    So you cannot expect to modify something in an ICC profile that changes actual display behavior.

    To do what you want you must:
    A) work only on color managed enviroments, which is not possible on a windows desktop, only inside color managed apps.
    B) modify monitor behavior before DisplayCAL profiles it. This can be done:
    B.1) with and AMD adn EDID sRGB emulation
    B.2) with sRGB factory preset in your display, if available
    B.3) using 6-axis controls onmonitor OSD (or some more simplified RGB “saturation” control, WHICH ARE NOT “RGB gains” FOR WHITE) so resulting “emulated” R G & B primaries are a mix of native RGB primaries and such mix brings them closer to sRGB ones. Usually you do not need to modify blue.

    IDNK which monitor you have, or how big is it compatred to sRGB (missing data or image although your previos capture looked very sRGB -like), but since it seems that you are using Windows, non color managed apps and you do not own an AMD card, then you should go to your monitor manual and look for what I’ve described in B2 & B3. If your display has none of them, then return monitor for refund and buy a sRGB-like monitor (and AMD is another option but I think it will be erasier to return monitor)

    #25966

    Christopher
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    Then optionally it can store grey calibration (and white is a grey) in VCGT tag. That’s DisplayCAL or i1Profiler grey calibration stored inside ICC profile.

    The gray calibration & white are stored inside an ICC profile only when using DisplayCAL and a i1 Profiler ?

    The display which I use supports HDMI-1 port specially supports few uncertain HDMI1.4 EDID devices.

    #25973

    Vincent
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    Then optionally it can store grey calibration (and white is a grey) in VCGT tag. That’s DisplayCAL or i1Profiler grey calibration stored inside ICC profile.

    The gray calibration & white are stored inside an ICC profile only when using DisplayCAL and a i1 Profiler ?

    No, with other GPU Calibration software will happen the same. For example Basiccolor if your computer has no support for HW calibration with it, or i1Studio software.

    Profiling software (with GPU/HW cal… or whatever)=> create profile that describes display
    GPU calibration software => also includes in VCGT tag inside profile white & grey calibration

    • This reply was modified 4 months, 2 weeks ago by Vincent.

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