Srgb or gamma 2.2 as the tone curve?

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  • #33746

    CALmelion
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    Indeed those are the things that are NOT color-managed, and so will be most affected by the display’s tone curve. Applications that ARE color managed should display images the same regardless if i’m not mistaken, as they’re using the monitor profile created after calibration, but the interface might not. Some browsers are aware of the monitor profile, some not.

    #33747

    Vincent
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    I have yet to find out how to deal with how color-managed things look, versus how most other devices display it.

    Reply To: Srgb or gamma 2.2 as the tone curve?

    Let’s say that you are going to build a color management engine.
    You have to render sRGB images in a display with a  single TRC and matrix primaries.
    sRGB output for RGB 000 is expected to be 0, RGB 1,1,1 is expected to be <apply sRGB TRC>

    Now apply what I’ve said
    a) if TRC in display ICC says infinite contrast and display is RGB OLED
    b) if TRC in display ICC says infinite contrast and display is 100cd/m2 and 1000:1. How do you render RGB 000 and RGB 1,1,1?
    c) if TRC in display ICC says  finite contrast ( RGB 0 -> non 0 light output) and display is 100cd/m2 and 1000:1. How do you render RGB 000 and RGB 1,1,1?

    TL;DR
    if you “fake” a sRGB TRC in ICC (“infinite contrast”, “BPC”), although that curve is lower than 2.2 near black, predicted ouput near black will be much lower than what a display with finite contrast lifted  can provide. “Actual” TRC is lifted too much near black to keep sRGB TRC shape. Mismatch is too big.
    if you do not fake “ininite contrast” in TRC, inside display ICC, some “simple” color managed apps or engines may “clip” out of gamut near black colors…. because they’are actually out of gamut.

    • This reply was modified 4 months ago by Vincent.
    • This reply was modified 4 months ago by Vincent.
    • This reply was modified 4 months ago by Vincent.
    #33751

    Vincent
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    Applications that ARE color managed should display images the same regardless if i’m not mistaken, as they’re using the monitor profile created after calibration,

    IF profile and actual display behavior match.

    Mismatch between “idealized” (with BPC active, RGB in 0 -> 0 out ) display profile with a TRC that has sRGB TRC “shape” and actual TRC obtained calibrating to a “lifted” (non clipping) sRGB TRC target in a low contrast display will be too high near black. In other colors not so dark, profile TRC and display TRC will match.

    Color managed apps trust what display profile says.

    #33752

    CALmelion
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    Thanks, the workings of it have begun to dawn on me.

    What i meant by that bit though is how to deal with the vast majority of devices clipping things, while some are not. As this makes a huge difference in contrast and the look of an image, it’s difficult finding the right balance between (color managed) editing and the results as seen by others.

    While you can proof sRGB color, and even paper, it’s a little more difficult with crushed blacks as it will be different for everyone.

    #33753

    CALmelion
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    Applications that ARE color managed should display images the same regardless if i’m not mistaken, as they’re using the monitor profile created after calibration,

    IF profile and actual display behavior match.

    And if your display is set to 2.2 but you’ve calibrated to sRGB TRC, then they don’t?

    Mismatch between “idealized” (with BPC active, RGB in 0 -> 0 out ) display profile with a TRC that has sRGB TRC “shape” and actual TRC obtained calibrating to a “lifted” (non clipping) sRGB TRC target in a low contrast display will be too high near black. In other colors not so dark, profile TRC and display TRC will match.

    Color managed apps trust what display profile says.

    So a bit of a lowered contrast situation for the color managed images as well then.

    • This reply was modified 4 months ago by CALmelion.
    #33756

    Vincent
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    Applications that ARE color managed should display images the same regardless if i’m not mistaken, as they’re using the monitor profile created after calibration,

    IF profile and actual display behavior match.

    And if your display is set to 2.2 but you’ve calibrated to sRGB TRC, then they don’t?

    You did not calibrate to sRGB TRC because you’ll clip on a low contras display, same to 2.2.. You calibrated (typical scenario) to a “lifted” sRGB TRC if your display is low contrast. If you measure “raw TRC” of that display is not sRGB near black.

    Mismatch between “idealized” (with BPC active, RGB in 0 -> 0 out ) display profile with a TRC that has sRGB TRC “shape” and actual TRC obtained calibrating to a “lifted” (non clipping) sRGB TRC target in a low contrast display will be too high near black. In other colors not so dark, profile TRC and display TRC will match.

    Color managed apps trust what display profile says.

    So a bit of a lowered contrast situation for the color managed images as well then.

    No. Input 0 on image will ouput 0 to display. Contrast will be the same as non color managed (unless you softproof to paper of course). First greys will be lifted “out of their place” depending on mismatch between display TRC and ICC TRC. The higher the mismatch the higher the lift vs ideal infinite contrast display.
    (I’m talking about a display ICC profile with BPC, “fake infinite contrast” on TRC)

    • This reply was modified 4 months ago by Vincent.
    • This reply was modified 4 months ago by Vincent.
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