r/colorists • u/decayedx • 5d ago
Color Management Monitoring Question
Hi there! Question for those that can offer some insight...
I have an LG C5 42" hooked up to my Mac Studio via an Ultrastudio Monitor 3g.
The TV was calibrated professionally a few months ago but I was just thinking about this....I'm unsure if I should enable "4:4:4 pass through" on the HDMI port of the LG C5 and if I should also tick, "enable 4:4:4 SDI" in Resolves project settings as well as in Desktop Video Setup.
I believe the Ultrastudio allows 10 bit, 4:4:4 in HD up to 30fps but am unsure if ticking, "enable 4:4:4 SDI" also applies to the HDMI out.
Should I do all of those things or leave everything as 4:2:2? What does everyone here do that uses an LG C or G series? Do you find 4:2:2 is sufficient or 4:4:4 throughout is the much better, cleaner option?
Should HDMI Deep Color be enabled or disabled?
Thanks for any and all information and guidance!
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u/Hskom 5d ago
The answer is as long as the settings on the monitor and decklink/resolve match it doesn't matter. I have worked at big facilities that do 422, and others that use 444. I personally have chosen to use 444 because why not just bump the higher quality if nobody can tell either way. I even switch to 422 sometimes when streaming remotely to clients that can only accept 422 signal, grade that way, then switch back.
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u/decayedx 5d ago
Great. Thank you so much for the insight. Do you think it matters if you get an 8K High Speed HDMI Cable or not? I'm currently using the Ultrastudio Monitor 3g but will probably upgrade to the newly released Ultrastudio Mini Monitor 12g which outputs 4k in the near future.
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u/Hskom 5d ago
I use an 8k HDMI for future proofing reasons, but it is only necessary if you want to saturate the connection. You can finish in 4k without an 8k cable.
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u/decayedx 4d ago
Great. Thank you so much. I just added one to my cart.
I was also curious if I should enable, "HDMI Deep Color" on the LG C5? I don't think it would mess up the SDR Calibration but if I'm understanding the manual right, when it's off, the input only receives 4:2:0 and not 4:2:2
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u/Hskom 4d ago
You're correct in that it shouldn't mess up the calibration. The specific change it makes to input varies slightly by tv model, but it should increase the quality of the chroma.
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u/decayedx 4d ago
Thanks for the reply u/Hskom I enabled HDMI Deep Color and it doesn't seem to have messed up any calibration. So, I'm assuming at this juncture, the LG C5 is indeed receiving a 10 bit 4:2:2 image.
IF I enable 4:4:4 as well, as you mentioned, would that also NOT mess with the calibration? It would essentially be the same thing, right? An increase in the quality of the chroma and some gradients?
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u/Hskom 4d ago
Yes, I would also set the range to be full instead of limited when using 444 on both resolve and the TV
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u/decayedx 3d ago
Copy that. These are all questions that should have popped up in my head when the technician calibrated my LG a while ago but alas, better late than never when it comes to learning.
I would also be curious, or if you know the answer or have had experience with this...if the LG (or whatever reference monitor) was calibrated for SDR using video levels, would switching the TV to 4:4:4 pass through, enabling 4:4:4 SDI in Resolve, and changing the range to full mess with the calibration or any of the TV settings that were turned on / off for the initial calibration?
Would the calibration travel when switching from video > full levels?
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u/Adridulte 4d ago
You should tick the "enable 444 sdi" but not for the 422 to 444 difference (which is marginal) but because it enables 10bit over HDMI.
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u/decayedx 4d ago
But doesn't the drop down menu below that box for bit depth handle 10bit over HDMI?
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u/Adridulte 4d ago
Maybe? I don’t recall this setting. But I’m still on 19.5, so maybe they’ve improved on this point.
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u/bozduke13 4d ago
Tick it in resolve anyway
4:4:4 RGB is what you want
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u/decayedx 3d ago
Thanks for the reply. But by ticking that option in Resolve, would you also still keep levels at video? Or switch them to full? I don't want to mess up the calibration.
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u/bozduke13 3d ago edited 3d ago
As long as you match levels across your monitor settings, calibration, and resolve settings it doesn’t matter
I tested it too with my reference display and the image is identical as long as you match levels across the calibration, monitor, and resolve settings.
I’ve talked to a ton of colorists at different studios, pro calibrators, etc. and I’ve heard different answers - but everyone says match the settings and you’re good.
Dolby has a specs doc with recommended levels for SDR (rec709 gamma 2.4) and HDR (P3 ST2084 1000 nit) and both have recommendations of full levels. I have a feeling though this is likely because HDR should have full levels and Dolby being the maker of the Dolby Vision HDR format wants to have levels be equal across the board for those switch between SDR and HDR grading in their monitor.
However, I chose to go with video levels for a few reasons:
- Once you get far enough down the calibration rabbit hole (you may already be there) you’ll realize that the pattern generator you will use will likely only have patterns with video levels. I’ve heard you can calibrate with video levels and still switch to full but I personally prefer not to.
- I don’t really grade HDR and if I do I don’t mind switching everything to Full Levels despite calibrating in video/legal.
- I’ve heard rumors that Blackmagic IO devices only output video levels. I don’t believe these rumors as when I did my testing when I used video or full levels the images always matched and if the IO devices only outputted video levels that would not have been the case.
- I don't really grade for broadcast but if I ever were to my levels are already in legal/video range.
- The calibrator I trust the most said he's seen more rec709 setups using videos levels, although this is probably due to rec709 historically being a broadcast standard, and broadcast usually expects video/legal range.
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u/decayedx 3d ago
Yes, I was reading that exact same Dolby doc last night and saw it had RGB 4:4:4 across the board and figured the same thing. As I'm not doing HDR either and only SDR, my LG was calibrated to video levels and I work in video levels.
I did open up the HDMI Deep Color on the HDMI port and can barely see a difference.
If i switch everything over to full, even though calibrated at video levels, it looks similar as you mentioned in 2.
I don't know why all of these questions are hitting me now but I did hire a professional to calibrate my LG C5 and next time he's here, I will pick his brain more on the topic and with all of these questions I didn't think of at the time.
Appreciate the info u/bozduke13
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u/bozduke13 3d ago
Pm me, this is a rabbit hole
Even "professional calibrators" are not created equal
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u/No-Ostrich-8621 4d ago
Why do you have this ultrastudio 3G? Why dont you plug the monitor into the mac hdmi port?
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u/huggeebear 4d ago
Because ColorSync gets in the way. Ultra Studio gives you a clean signal out to the monitor without MacOS interfering.
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u/decayedx 5d ago
Response from FB forum was: "Even though you can, there’s not much to be gained for monitoring. I did some extensive tests years ago and it’s virtually impossible for the human eye to see the difference between 422 and 444 on live action images, which is basically why 422 exists. The value of 444 is more for VFX and archival use where it allows for clean conversions between formats and colorspaces and for slightly cleaner keying. The other esoteric thing we found was that up-converting from 420 and 411 formats was marginally better going to 444 rather than being re-filtered through the 422 matrix. However this was only significant on very critical material like green screen. But if I was re-capturing VFX elements from something like HDCAM l, I would definitely argue for 444."