Why using sRGB over BT1886 ?

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  • #141347

    Guillaume
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    There is many monitors reviewers that use sRGB as target and not BT1886. Is there a reason behind this ? Or should they target the BT1886 EOTF instead ?

    #141351

    Vincent
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    There is an sRGB gamut boundaries and sRGB TRC. Also I see no reason to use Rec1886 on 1000:1 displays.

    #141354

    Guillaume
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    Yeah I noticed that a 1000:1 display calibrated to BT1886 is more or less sRGB curve. But for a VA monitor, like my primary monitor, is BT1886 objectively better ? Rtings uses sRGB for all monitors even for OLED and I think it’s wrong but I could have missed something. And also for TVs they always target gamma 2.2 where I think it’s wrong too. Could my 10 years into calibration confirm my feelings about these test methologies ?

    #141356

    Ben
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    BT1886 has higher blacks and looks less contrast on a 1000 contrast display.    It is a challenge for good contrast and good blacks on 1000 contrast display.  I like native contast on my Vizio V 5-555-J01 tv.    HCFR will show you the native contrast.   If you have  10 or 20 point white balance you can get good white balance without crushing black by not turning down 5,10,15 white balance rgb.   You need to use a meter and have a well behaved screen.   Check the 1% black.      On mine it is raised compared to the 2%.   It probably done on purpose at the factory.     I see 1% and less on native gamma 2.2 but on displaycal gamma 2.2 it is very hard to see 1% or less.  http://www.lagom.nl/lcd-test/black.php   .     Difference is 1st row is dark vs 1 dark only.    On native I can switch to 2.4 gamma and see in a dark room.  The 1st row is very dark on 2.4    2.4 gamma is like bt1886 on a oled screen.

    #141357

    Ben
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    SRGB is not wrong.  It is has less raised blacks than bt1886 on the 1000 contrast displays.   Oled can have black crush worse and raised blacks is something you can see on them versus black crush.    2.2 gamma is good for a lighted room.   People watch tv in a lighted room sometimes.

    A factor is also the nit brightness.   2.4 is better at higher nits.

    • This reply was modified 1 month, 2 weeks ago by Ben.
    #141359

    Guillaume
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    In fact I calibrate monitors to BT1886 for quite a long time so in fact they don’t calibrate with the good target. In fact for a well lit room changing the black levels is better cause it matches more cones’ threshold. Like making a SDR version of Dolby IQ or HGiG. There is informations there.

    #141360

    Vincent
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     Rtings uses sRGB for all monitors even for OLED and I think it’s wrong but I could have missed something. And also for TVs they always target gamma 2.2 where I think it’s wrong too. Could my 10 years into calibration confirm my feelings about these test methologies ?

    Rtings hardly knows what they are doing. The post calibration image is like using on DisplayCAL simulate sRGB on a custrom matrix + 3curves profile with no grey calibration at all.
    Mostly useless as a source of computer display reviews.Best use pard.de but they review less displays.

    Download one of their custom ICC profiles and inspect them with ICC profile isnoecto or “DisplayCAl-profile-info.exe path_to_icc\rtings.icc”

    • This reply was modified 1 month, 2 weeks ago by Vincent.
    #141369

    Ben
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    Just my memory that gamma 2.2 2% hcfr input offset matched my native 2.2 gamma.    But displaycal has been make luts starting at 145-170 instead of native 256 and around point 40 of 255 they start to match very closely.    It makes my blacks crushed visualy.    Well my screen is wierd and the red and green cross from 1 to 40.   Fixed with raising green at 5% to match red almost.   In the end displaycal is better.  It is just harder see.  however each number in lagom lcd test a different brightness visually and can see on contrast the white is not blueish at 1 , 2 and 3 in the contrast chart and is smoother increase in brightness.   Still get errors like  2024-05-18 23:19:30,696 Failed to meet target 0.400000 delta E, got worst case 1.727526     .     and 2024-05-18 23:19:30,684 Patch 96 of 96 DE 0.001315, W.DE 1.314525, W.peqDE 1.314525, Fail ( > 0.250000)    .      Those are very rare not to get and usually only dont get any if I do not touch and white 20 point controls and that is only with fast speed quality.   The good qualiy speed always fails something.

    #141397

    Guillaume
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    I’m convinced that using BT1886 for display calibration is the best approach we can have for SDR. But L* with a black output offset, or input, may be better. But here I can’t find any sources to know exactly how the eyes luminance response looks like in the best viewing conditions. So I stay with BT1886.

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