Need some advice on calibrating an Eizo CS2740

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  • #27091

    Firebird
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    I’m hoping someone can help me understand how best to do this properly – I’ve been reading vast amounts of information from all over the place, and it’s hard to keep it all straight in my head!

    The easiest option would obviously be to just use CN7 and trust that it’s correct, but I don’t like to just trust things like that, I like to poke around and make sure of things, and figure out what it’s all actually doing… I’d like to at least find out how accurate the CN7 results are, and whether I should trust them or maybe use a profile made with Displaycal along with them. I assume that it’s generally best to use hardware calibration if the monitor has it? Is this mainly to prevent banding?

    In case other hardware is relevant in any way, my GPU is Nvidia GeForce GTX 1060 6BG (output set to 10bpc), and the monitor is connected via DisplayPort.

    I’m not sure what specifically the hardware calibration part does in the CS2740, does this just handle grey levels (and therefore white?), and gamma? CN7 creates a profile as well, which is applied automatically and shows as default in Displaycal profile loader, which I guess has a lut for colours?

    What I have done so far is I have used CN7 to calibrate a slot to native gamut, D65, gamma 2.2 , with black level to minimum and brightness at 180cd/m2 – I figured I should stick with native gamut and not limit it, as I’ll be using colour managed software, which should handle displaying sRGB etc.  Is this correct? Am I likely to have any issues from the brightness level? I work in a brightly lit room, and prefer a bright screen, but would consider lowering that setting if necessary (I’ve already lowered it from my standard eye-scorching 250+ on my old monitor). I’ve run validation on this in CN7, which of course tells me it’s fine… It would be nice to be able to use (and trust) the colour modes, and easily switch between them.

    I can’t load the icc file CN7 creates into Displaycal to check it, I get a message saying it contains no settings, but I have attempted to verify the results by selecting the display and a correction, then generating a measurement report. I’ve also done one with sRGB as a simulation profile, which I believe should show how well sRGB images will display in colour managed apps? I’m not sure if I’m using the right correction though – after reading several posts on this forum I went with the PFS Phosphor WLED (HP Z24x G2), is that my best option for the CS2740? I’m using an i1Display Pro Plus. I did find a couple of similar(ish) recent Eizo models in the database (CG319X & CS2731), but I’ve no idea if the backlight is the same, or if the data in them is even accurate/relevant/useful to me. Also they were matrix corrections, does that make a difference? The CG319X correction was 1nm, which always catches my eye…

    Basically I would love to get some opinions on how to proceed from people who know this stuff better than I do. I’m hoping to get the colours as ‘accurate’ as possible, by which I mean (as best as I can describe it), displaying colours so that they appear on screen visually as close as possible to the standard accepted physical definition of that colour (Lab values etc). I know it’s possible to talk for at least 6 hours non-stop about all the reasons that’s not going to actually happen, and get philosophical about what even is ‘accurate’ or ‘colour’ anyway (which people elsewhere have done when I mentioned ‘accuracy’), but getting as close as possible for our set up is why we’re all here, right? 🙂

    I’ve attached some files below that are hopefully useful, including a CN7 screenshot showing the calibration target and results, and basic overview results of validations done after calibration – these show what look like some drifting, but I don’t know how strong it is as I don’t know how well to trust CN7, and Displaycal gives different dE values for things, I guess due to the correction used? On this note, I also used an online dE2000 calculator and the xy coordinates detected by Displaycal’s whitepoint editor while using different corrections to see what came closest to CN7’s results, or at least had the lowest dE compared to standard x:0.3217 y:0.3291, and the 2 with the ‘best’ results were the LCD PFS Phosphor WLED family and Spectral:plasma corrections, of which plasma seemed ‘best’ of all (dE between 0.202 and 0.089 testing over 4 hour period). I say ‘best’, but I’ve no idea what I’m doing there, I had some idea that these measurements might point towards the most appropriate correction to use, but I was very tired at the time, and that might not be true at all… Was it a mad plan? How important even is the white point? Isn’t that the point all the colours are based on?

    I’ve also included the 2 reports I mentioned above, could someone offer an opinion on whether they look like what you’d expect from an Eizo CS2740? Can I do better? I’m happy to put the work into getting it as good as possible, as long as I can be sure I actually understand what I’m doing… I think I built my knowledge to a critical point where I realised how much I DON’T understand, and now I’m not sure I know anything.  -_-

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    #27103

    Vincent
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    CS Eizos likely to use GB-LED, but maybe they are using WLED PFS AdobeRGB+P3 in newer models
    Newer CGs are the ones with WLED PFS HP Z24x

    Calibration report is flawless:
    -That mild dE close to black is caused because CN ICC stores that black is perfect, infinite contrast (a trick to avoid Photoshop or LR fixing things at limited precision). CN creates a profile describing display in a very idealized way. It is close to what you get if you create a “single curve + matrix with BPC” on DisplayCAL. It is made that way on purpose, those mild dE is a lesser evil compared to some rounding errors caused by color managed apps using limited precision on a realistic ICC profile.
    -dE to assumed white is likely to be caused by CN and DisplayCAL using different colorimeter correction.
    -contrast is a little low but all reviews agree with that on that model  ~800:1 at D65 rather than nominal 1000:1 value.
    -grey is astonishing perfect, look at RGB + grey balance.

    So do nothing, or check usng GB-LED ccss correction.
    If white color bothers you visually, a slight pink or green cast, just use CN visual whitepoint, move white a little in a* axis till you see a better white.

    #27118

    Firebird
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    Hi Vincent, thank you so much for the advice and explanation! I’m really happy to know I can trust my display and CN7’s calibration, it makes things much easier to manage. Am I right in thinking there’s not much advantage to be gained by making any sort of profile with Displaycal in this case?

    If I wanted to check things with the GB-LED correction you mentioned, which Displaycal option should I choose? I had a look around and found a reply you left for someone saying that the option labelled Dell U2413 counts as a GB-LED correction, is that the right one for me as well? I tried a very quick verification (51 patches) with this and got very slightly worse de2000 results:

    • measured vs assumed whitepoint – HP Z24x: 1.6  Dell: 3.5
    • Measured vs. display profile whitepoint – HP Z24x: 1.45  Dell: 3.19
    • average dE – HP Z24x: 0.29  Dell: 0.34
    • 99% percentile ΔE*00 – Z24x: 1.41  Dell: 1.58

    I’m guessing since the white point is further out, this might not be a better correction to use? Or am I thinking completely wrong about how white point comes into this?

    Do you think it’s worth contacting someone at Eizo to ask about the specific type of backlight and what corrections should be used?

    #27121

    Vincent
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    Hi Vincent, thank you so much for the advice and explanation! I’m really happy to know I can trust my display and CN7’s calibration, it makes things much easier to manage. Am I right in thinking there’s not much advantage to be gained by making any sort of profile with Displaycal in this case?

    Ideal profile fits display so for photoshop/LR/C1 use CN IC profile.

    If you want to make a LUT3D from X colorspace to your current display colorspace I would say yes… but a colorimetric relative intent with CN profile should be visually ok.

    If I wanted to check things with the GB-LED correction you mentioned, which Displaycal option should I choose? I had a look around and found a reply you left for someone saying that the option labelled Dell U2413 counts as a GB-LED correction, is that the right one for me as well? I tried a very quick verification (51 patches) with this and got very slightly worse de2000 results:

    • measured vs assumed whitepoint – HP Z24x: 1.6  Dell: 3.5
    • Measured vs. display profile whitepoint – HP Z24x: 1.45  Dell: 3.19
    • average dE – HP Z24x: 0.29  Dell: 0.34
    • 99% percentile ΔE*00 – Z24x: 1.41  Dell: 1.58

    I’m guessing since the white point is further out, this might not be a better correction to use? Or am I thinking completely wrong about how white point comes into this?

    Seems to be further away

    Do you think it’s worth contacting someone at Eizo to ask about the specific type of backlight and what corrections should be used?

    It should be stated in item description before buying. It’s a shame that reviewers like prad.de do not show SPD on all reviews. Try to ask.

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