Calibrating rec709 iMac Pro & Proper Linear Workflow

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  • #25323

    MisterE
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    Hello

    I’m trying to setup proper color calibration on iMac Pro with DisplayCal and xrite i1Display Pro Plus for working in Adobe apps, for Video, Photography and Web. I haven’t calibrated a monitor in a long time so could use some advice to make sure I do it properly. I don’t want to mess it up and then tweak all the comps and footage in my current project only to find out it was incorrect. Getting a proper monitor isn’t possible now, so I just need to get the iMac Pro display calibrated as good as I can.

    Primarily, I’m using Adobe After Effects 2020 and Premiere Pro 2020 along with the rest of Adobe apps to create 4k video content for YouTube. I work in 32-bit per channel linear and typically set my color space in After Effects to Wide Gamut RGB, I output to 16-bit ProRes 422 which gives the best results when uploading to YouTube. This space was suggested to me by Adobe and seems to provide a lot of control when pushing tones and color. They said to just output to rec709 color space when rendering for Premiere since rec709 is native to it. This sort of worked—exr and ProRes files looked right when editing in Premiere, but the colors were off when Premiere exported a final ProRes 422 video.

    I’m not sure if the color space was the problem or if  my monitor not being calibrated was, or both. After doing a quick calibration set to rec709 in DisplayCal and watching one of my videos I output directly from AE as sRGB ProRes422, it looked a lot like incorrect output from Premiere—brighter in the shadows and a bit washed out, though the reds were vibrant. So it may just be the calibration.

    For Photography I typically like to work in ProPhotoRGB space in Photoshop in 16-bit as I’ve had the best results using that color space, even with my monitor not being calibrated.

    For the web, I’m not sure if I need a separate calibration for sRGB or if a calibration for photos would also suffice for web.

    Anyway, any advice is welcome on how to properly calibrate this iMac Pro to have more accuracy when I’m working on video, photography or web work, and any advice you may have on linear workflow in Adobe apps. I assume having separate profiles is the way to go. I just need to ensure the profiles are made correctly.

    Thanks

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    #25327

    Vincent
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    It seems that you have no calibration issues, just “working colorspace” issues (=configuration of Adobe Suite).

    For working with Adobe suite you just need that you have your desired whitepoint and an accurate display behavior description stored in an ICC, and that ICC is set as display profile in OS settings, since latest CC2020 Premiere seems color managed but IDNK how good it is, maybe just a fast GPU assisted transfromation.

    For viewing “final product” video you need a reliable color managed video player. IDNK it QT is one of these regarding gamma, maybe you want to check mpv.

    When exporting final product you need to convert it to client/customer/service colorspace, meant to be viewed in some conditions/display. Those are typical Rec709 g2.4 or g2.2.

    For working with photos is the same, you work in some image colorspace and that gest translated realtime to whatever your screen capabilities are.
    For exporting final product for web, just convert to sRGB, no separate calibration is needed. Some colors may fall outside sRGB, so final product may look off or clipped, so just use Photoshop softproof utilities to sRGB while you edit to see that in advance.

    Summary:
    If video/photo editing/viewing apps are color managed you just need ONE display profile with GPU(grey) calibration. Typical D65 white and near native TRC which is ussually 2.2
    You may want other calibrations with warmer whitepoints for printing… you if you want that, you bought one of the worst display: a mac, because an Imac is just a big laptop with locked OSD controls for whitepoint. Anyway, it looks that this do not apply for you since you edit for web and video = D65

    • This reply was modified 4 months, 3 weeks ago by Vincent.
    #25341

    MisterE
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    Thanks for your reply.

    In After Effects, the only profile option is Rec709 gamma 2.4 (not 2.2). So if I calibrate my monitor to Rec709, then I just set the profile to that in AE I assume? Attached is the color management window as I have it currently set in AE.

    This is one discrepancy I’ve seen repeatedly—whether to use gamma 2.2 or 2.4 (with disagreement on what’s best). In DisplayCal, under Tone Curve, it has either Gamma 2.2 or Rec709 (and some others), so I assume Rec709 is what to choose. As I said above, AE’s only setting is for 2.4 with Rec709.

    As far as DisplayCal in Calibration tab, I assume I have to disable “interactive display adjustment” since I can’t adjust the RGB values on the iMac Pro screen, and then set “Whitepoint” to 6500K and white level “as measured?” Ambient light level I can measure with my i1.

    Is there any benefit to generating a 3D LUT for Adobe apps? That’s something I’ve also never worked with before. People seem to use them a lot with Resolve but I don’t have that.

    I’m still unsure about going from AE to Premiere (if any changes to output settings are needed so Premiere doesn’t mess with colors upon output). Hopefully if I tweak everything in AE working in Rec709 then Premiere will behave. 🙂

    P.S. Trust me I would have preferred a mac pro with a proper display like an Eizo monitor, or a mac for my audio and a windows workstation for graphics, but when I got this machine the pro wasn’t out yet and I already had licenses for mac I couldn’t transfer to windows. Is what it is for now. Hopefully this coming year I can upgrade my hardware.

    Thanks

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    #25343

    MisterE
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    Guess it would have been smarter to just post the images from DisplayCal, so here they are.

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    #25347

    MisterE
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    Here is the first screen again. I found a correction profile online on a photography site made for the iMac Pro screen.

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    #25351

    Vincent
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    You CAN’T calibrate an imac embebed display to Rec709 colorspace. There is no HW for doing that, your imac is not able to do that (it “may” be able to do that, at least in MS Windows with AMD GPUs sRGB gamut emulation). It may even have problems getting D65 bceause it’s just a big laptop screen (*)
    So just set D65 white point and near 2.2 gamma because it should be close to native TRC. Never set Rec709, it is not meant to be used for that. Then profile. That’s all you can do on a mac.
    With a more or less accurate display ICC profile if all apps are color managed they will transform content from whatever source colorspace (let’s say rec709) to display colorspace (let’s say near P3).
    -Adobe suite is color managed using their own color managemnent engine (not Apple’s), although IDNK if Premiere video rendering to screen is somehow simplified (take Rec709 content and transform that to an ideal P3 D65 g2.2 display)
    -IDNK accuracy of QT’s color management, so for testing/viewing exported content you may want to use a more reliable video player like MPV.
    -same for photos, rather that trusting embeded OS’ image viewer use a more reliable image viewer like PS. And use PS’ softprrof to sRGB to see gamut clipping when going from a ProphotoRGB/eciRGBv2/AdobeRGB image to final sRGB image

    Also for sRGB-like Imacs (older ones) correction is WLED (common white LED IPS correction for sRGB displays). For all new “P3” displays from Apple use the bundled correction in displaycal WLED PFS phosphor for P3 macs (there are 3 flavors, <95% P3 for gamming multimedia, “just P3” for newer macs, and AdobeRGB+P3 photo displays which are more advanceed that the other two)

    (*) You can choose to let DisplayCAL to correct whitepoint to D65 using GPU LUTs like in common laptops, but due to the buggy Apple’s color management engine for desktop you may experience some artifacts, hence DisplayCAL default settings.

    • This reply was modified 4 months, 3 weeks ago by Vincent.
    #25353

    Vincent
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    Also do not use ambient light compensation with color managed apps.
    All to default, D65, g2.2, proper spectral correction for whetaver iMac you have.. and that’s all you can do,

    #25358

    MisterE
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    Thanks for the info. My iMac Pro is 2018 so I think it’s P3.

    I chose “Office & Web (D65, Gamma 2.2) from the Settings dropdown. I changed the correction to LCD PFS Phosphor WLED IPS P3 (Macbook Pro Retina 2016). In Calibration tab I just changed the speed to Medium. I didn’t touch Profiling tab or Verification tab. Hopefully I have it closer to correct now…

    Attached are the settings.

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    #25363

    Vincent
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    Verification, when you calibrate and get resulting display profile is a little different than what you think:
    -all disabled: check if display matches profile <<< Usually just run this verification
    -simulation profile, all the other unchecked: check how display profile behaves when color managing some image encoded with simulation profile
    -simulation profile and suse simulation as display profile: DISABLE GPU grey calibration, check if display AS IS matches or does not match simulation profile. <<< YOU DO NOT WANT THIS on a mac …but you may want it to check how good is factory calibration to P3 D65. This setup is sused to verify factory calibration or HW calibration like those NEC or Eizos with arbitrary gamut emulation, but since a mac has not such features you can use it inly to verify factory calibration to P3 D65.

    Also if you experience artifacts or corruption in OS UI elements like finder bar or menus then instead of “Office & web” use default setting for mac (and its associated display native white, not D65)

    • This reply was modified 4 months, 3 weeks ago by Vincent.
    #25365

    MisterE
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    Thanks.

    I ran it two more times. The past 5 or so calibrations I ran with D65 gamma 2.2 look almost the same—they had a bit of a yellow cast and the grays seemed too washed out. However, the last one I ran using the “Default (Gamma 2.2)” setting looked better—more neutral, more contrast in grays and not so washed out. Will try this out this week and do a bunch of tests with my project.

    Checking between the factory profile and all my early calibration attempts, the gamma was definitely off—subtle dark grays near black were too dark so I couldn’t see them, even in 32-bit float. With the new calibrations I can see way more of those faint tones as they blend into black, very good when doing glow effects and such. With the last few it seems that reds and oranges are a bit more vibrant. Not sure if this is accurate, just noticed it. From what the calibration meters are showing, these iMac displays seem to sway heavily into the blue.

    I’m going to post on Adobe forums and see if they have any info about getting accurate colors between AE and Premiere including rendering finals. What you said earlier is what I always thought: Work in what you want in AE and just convert the colors when rendering. That seemed to work for me going between AE and Photoshop when doing web stuff even without calibration, but Premiere is odd. I think it ignores embedded profiles or something.

    Tomorrow I’ll check out that video player you mentioned. I usually check my stuff in QT, VLC and then upload to YouTube to check in browsers since that’s where it will be seen. Worst case, I’ll just render from AE and deal with the longer render times.

    Much thanks for all the time and help with this. I really appreciate it. This stuff makes my head hurt so much I’d rather hire someone to come and set this stuff up for the rest of my life 🙂

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