Srgb or gamma 2.2 as the tone curve?

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  • #33622

    Il Minu
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    Srgb or gamma 2.2 as the tone curve? And why?

    #33632

    Vincent
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    Plot them and you’ll see. X RGB input, Y gamma value. Unless you have an infinite contrast display gamma needs to bend in the lower end.
    Usually you do not want sRGB TRC (relatively lifted to match your non ideal black) for non color managed content like video on a common sRGB display.

    #33708

    Il Minu
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    What are color managed content? Is gamma 2.2 lower end gamma? However I tried both tone curves, with the srgb curve a black shirt (before calibration) becomes for example gray, while with gamma 2.2 it remains black. I guess the second one is more correct? One last thing, checking the calibration I got a bigger average error with the gamma 2.2 calibration than with the srgb tone curve, why is that?

    • This reply was modified 3 days, 5 hours ago by Il Minu.
    #33709

    Vincent
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    Content encoded in a known colorpace (or a supposed one) showed in a color managed application.

    #33711

    Il Minu
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    Sorry, I edited the message, could you take the guesswork out of the other questions as well?

    #33718

    Vincent
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    What are color managed content? Is gamma 2.2 lower end gamma? However I tried both tone curves, with the srgb curve a black shirt (before calibration) becomes for example gray, while with gamma 2.2 it remains black.

    Explained in previous message.
    Finite contrast display showing content from an infinite contrast colorspace. You can choose whatever target TRC you want (target “gamma”) but when profile is made and calibrated display is measured (actual display TRC is measured), if you choose to “lie” (BPC) so profile stores a fake infinite contrast TRC to avoid clipping in color managed software without proper BPC, color managed software is applying the correction computed from “fake” TRC.
    The less contrast display has with a BPC profile the bigger the error.

    Choose the lesser evil. With color managed apps you may want to stick with closest to native neutral grey TRC because color managed software will undo it.

    One last thing, checking the calibration I got a bigger average error with the gamma 2.2 calibration than with the srgb tone curve, why is that?

    Checking calibration and verifying if display matches profile are two different things. IDNK what you did. Your display may be further away from those TRC targets and correction may be so high that GPU cannot handle it peorperly. Also your error differences may be meaningless.

    • This reply was modified 3 days, 4 hours ago by Vincent.
    • This reply was modified 3 days, 4 hours ago by Vincent.
    • This reply was modified 3 days, 4 hours ago by Vincent.
    #33724

    Il Minu
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    So you in conclusion recommend a TRC of 2.2 right? P.s I do not have an oled but an lcd.

    One guy told me that to take advantage of web content the srgb tone curve would be perfect. I’m referring to videos on youtube,netflix and other sites, at this point I guess he was wrong?

    Anyway thank you very much for your availability

    #33725

    Vincent
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    As I explained before you are mixing two concepts:
    -Actual display TRC after calibration
    -TRC reported by profile
    Color managed apps don’t care about 1st, they use 2nd and “trust” that both match.
    When you use BPC on profile you lie about 2nd to avoid that some software “do not know” how to deal with RGB values encoded in an ideal colorspace like sRGB where RGB=0,0,0 means 0cd/m2, hence these apps clip whatever image colorspace color that lies bellow actual cd/m2 ouputed by display at RGB 000 (TRC value at RGB 000).
    Other software have BPC in their color management engine so when image colorspace says “color at 0.00001 of white brightness” but display ICC profile  TRC says “RGB 000 has 0.001 of white brightness” (no BPC, finite contrast) it knows how to deal with it, do not clip and provide a perceptual lift of near black image colorspace to display colospace.
    In both cases if display ICC profile has BPC, “fake infinite contrast”, apps trust it and whataver mismatch you see is caused by TRC  in ICC display not matching actual TRC.

    • This reply was modified 3 days, 3 hours ago by Vincent.
    • This reply was modified 3 days, 3 hours ago by Vincent.
    #33729

    Il Minu
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    Okay, so what should I do? During calibration what settings should I put?

    #33736

    Vincent
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    2.2, D65, idealized profile. See how it performs.

    #33738

    CALmelion
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    So you in conclusion recommend a TRC of 2.2 right? P.s I do not have an oled but an lcd.

    One guy told me that to take advantage of web content the srgb tone curve would be perfect. I’m referring to videos on youtube,netflix and other sites, at this point I guess he was wrong?

    Anyway thank you very much for your availability

    Your friend was thinking about the color profile used for exporting/saving images, then yes use sRGB.

    But your display and everyone else’s monitor should have a native gamma curve of 2.2, and that’s probably what you should keep using if only to match what everyone else is seeing.

    Using sRGB as a display’s tone curve will make your un-color-managed desktop and any un-color-managed programs display sRGB images a bit more like they do when color-managed, but it will also make everything look flat, dull and unnatural compared to everyone else’s standard 2.2 gamma displays.

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

    #33740

    Il Minu
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    So a TRC of 2.2, for my use is the best setting right?

    #33741

    CALmelion
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    So a TRC of 2.2, for my use is the best setting right?

    You haven’t told us what your use is. 😉

    But as has been said, 2.2 is the standard or as “it’s supposed to be” so i’d say don’t mess with it.

    Also, it’s not like you only have one chance or die. Just try and see.

    • This reply was modified 3 days, 1 hour ago by CALmelion.
    #33743

    Il Minu
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    My day-to-day use consists only of enjoying multimedia content on the web and locally but mostly on the web. I am referring to content such as movies and series viewed on Netflix or other streaming platforms, videos on youtube and video games. However as you said before with a srgb tone curve instead of a 2.2 gamma, everything is less colored, more dull. So was it due to this? With a gamma 2.2 I should solve and see everything better?

    #33744

    Vincent
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    However as you said before with a srgb tone curve instead of a 2.2 gamma, everything is less colored, more dull. So was it due to this? With a gamma 2.2 I should solve and see everything better?

    Plot them and you’ll see. X RGB input, Y gamma value.

    Plot them. Wikipedia.

    • This reply was modified 3 days ago by Vincent.
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