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Calibration Signal Chain (Rec. 709) Resolve - Decklink - BMD 12G 3D LUT // Data vs Legal Levels

 
Author auteur
ZRO
Male
#1 | Posted: 21 Nov 2024 17:40 
Hello,

I'm setting up my monitor for Rec. 709 calibration and need some advice. My signal chain is:

DeckLink Mini Monitor 4K >> HDMI >> Blackmagic BiDirectional 12G (with 3D LUT) >> HDMI >> Monitor

I'll be using DaVinci Resolve as the TPG. I've read the excellent guides on the Light Illusion website multiple times and find the bold text incredibly helpful for inexperienced calibrators like me. If I may make a small suggestion, including a few more images, screenshots, or examples to complement the detailed instructions could make it easier to understand some of the more complex concepts or quickly locate the mentioned settings.

To help with this discussion, I plan to attach some measurements, including Grey Primary & Secondary Ramp+, using different settings in Resolve (FULL, LEGAL, use SDI 4:4:4), as well as testing both RGB FULL and YCbCr output from the DeckLink. While I consistently achieve dE2000 values below 1 across various combinations, I'm uncertain which configuration is correct.

I've also referred to the excellent Data vs. Legal Levels guide. However, I couldn't quite align the provided explanation with my results, and I'm unsure about the scaling method the BMD 12G Micro Converter requires. I've included attachments showing the decklink, BMD 12G, and Resolve settings I used, along with the measurement results for reference.

I've also included the EDID, though I'm not sure how helpful it is, as it uses a different HDMI signal and is connected directly to the monitor. The only potentially useful information I've been able to gather from the EDID are the R, G, and B coordinates, which I'm using to ensure I select the correct/native picture mode on my monitor to match its native color gamut.

Unfortunately, my monitor doesn't have a specific Legal/Full levels option, so I've adjusted the Black Levels to ensure 16 is the deepest black and 235 is white (clipping anything above 236).

Any clarification on the correct setup or how to determine the appropriate settings would be greatly appreciated. Thank you for your patience and support!

I've uploaded them below because they are larger than 2MB.

https://wetransfer.com/downloads/f9227816397d8c507df7edf18ebc3d0820241121174854/aa8a080d7552b2c9362bca9162e04d9620241121174927/2fe4da?t_exp=1732470534&t_lsid=3cfec4c3-c697-4971-9664-e4929c9aecf1&t_network=email&t_s=download_link&t_ts=1732211367

PS I dont have the ZRO license but the LTE
My plan is to also buy an HDfury Vertex/Integral2 in the near future so I can check my signal, but until then, I need to calibrate the monitor.

Colourspace Settings
Colourspace Settings
Colourspace ColorChecker Display Plus
Colourspace ColorChecker Display Plus

Author Steve

INF
Male
#2 | Posted: 21 Nov 2024 18:08 
Sorry to say not enough information provided.
Without knowing what your monitor is expecting as input levels, everything else is just guessing.
Just deciding to set the clipping levels is not the correct approach.
You will need to define exactly what the the monitor is expecting for signal levels.
Try profiling with a large grey ramp, and assess the differences with each different set of settings.

Steve
Steve Shaw
Mob Boss at Light Illusion

Author auteur
ZRO
Male
#3 | Posted: 21 Nov 2024 18:13 
Steve
Thank you so much for the quick response!

My monitor is an ASUS PA329C from the ProArt series.

I was wondering if you had a chance to review the .bcs, .cube files, EDID and the JPEGs that show what I'm seeing on the monitor? I've uploaded them to WeTransfer.
The .bcs with the dE2000 on the naming is those with the lowest dE. I verify with 3 or even 4 different scaling methods, obviously the 3D lut for storing it at BMD 12G needs scaling.

I understand that my IPS panel isn't capable of displaying true blacks, but I'm wondering how I can correct the clipping I noticed in the initial profile. I've tried adjusting the OFFSET settings on my monitor (R51, G51, B51), but this seems to negatively affect the excellent grayscale that the monitor has from the factory calibration.

Additionally, I didn't pre-calibrate the peak white before profiling, as the results in most scenarios seem to be acceptable, with peak white (100nits), dE2000 values below 0.5. However, since I don't have a spectrometer/spectroradiometer, I'm unsure if all these measurements are accurate. And also i dont know if i use the correct correlation file for my specific monitor.

displayspecification

Author Steve

INF
Male
#4 | Posted: 21 Nov 2024 18:35 
Sorry, that link was not there initially.
Unfortunately, you have thrown everything at the profiling, and there is now far too much data to assess.
If I get some free time I'll try to look, but I can't promise anything.
This really is asking for what we would consider consultancy work.

Steve
Steve Shaw
Mob Boss at Light Illusion

Author auteur
ZRO
Male
#5 | Posted: 21 Nov 2024 18:48 
Steve

Thank you for your message. I installed ColourSpace 9-10 months after purchasing it due to health and work commitments, which left me with little free time.

My monitor has been semi-calibrated for about 18 months now, so I'm happy to patiently wait for your response. Even if I don't receive an answer, I've learned a great deal throughout this bumpy journey of calibration.

I didn't pre-calibrate the peak white because I typically calibrate (or at least try to) late at night after jobs, and I end up sacrificing sleep, so I need to save some time. I've also profiled the monitor with both 17^3 and 21^3 LUTs, but I'm still experiencing the same issues with blacks (a reddish tint near black). the factory grayscale calibration is way better. i even try Augmented data without any benefit.

I wish I had a spectroradiometer and an HDfury dr.HDMI/vertex/integral2 to better check the signal and come up with clearer, more precise questions.

I truly appreciate your time and any help you can provide.

Author Steve

INF
Male
#6 | Posted: 22 Nov 2024 11:44 
Let's start from the beginning.
All monitors are basically Full Range displays.
Like any (most) displays, they can be forced to clip to Legal Range, but is that actually correct?
It may be better to use Resolve to re-scale at output from Legal (if that is your default timeline configuration) to Full Range.

So, I would initially set the monitor to its default state, and with Resolve set to your normal workflow configuration, including timeline, output range, video card, etc., profile the full signal chain via ColourSpace using a Large Grey Ramp.
Then assess that result to see if you get what is expected.
From there you can then define any settings issues.

As we often tell colourists, the issues you think you have with calibration are more often than not issues with the grading workflow, that the calibration results are highlighting.

Steve
Steve Shaw
Mob Boss at Light Illusion

Author auteur
ZRO
Male
#7 | Posted: 12 Jan 2025 18:35 
Although pretty good dE2000 0,16/0.20 at 1000 patches, i get a very bad calibration with reddish grey near black and high dE errors on low blue like (0,0,23)
I make a csv at 5% and 10% point at Blue and play around with monitors settings Six-Axis Hue/Saturation on Blue, offset (51, 51, 51) and (50, 50, 51) and other combinations without luck on the low blues.

tried pgen and resolve/decklink as a TPG, and also with correlation and without, i use colorchecker display plus with ColorSpace LTE (dont know why i have the ZRO below my nickname).

RGB separation is okish with Saturation at 51
50 are the default.

monitor settings are
Brightness
Contrast
Saturation = 51 fixes a little bit the initial bad RGB Separation
Hue = 50
Color Temp = 6500K
Gamma = 2.4 (even try 2.6 with offset at 51,51,51) to fix the bump at near black
Black level
Six-Axis Hue = tried some values on B, no luck
Six-Axis Saturation = tried some values on B, no luck
Gain=
Offset=

any help will be appreciated, thanks!

dE 0.16.zip Attached file:
ASUS NO COR B2 C80 S51 R50 G49 B49 17^

 
dE 0.20.zip Attached file:
B2 C78 S51 OFF B51 10^

 
ASUS RSLV BDM FULL 21^ NATIV.zip Attached file:
NATIVE DEFAULT SETTINGS

 

Author Steve

INF
Male
#8 | Posted: 14 Jan 2025 08:37 
I'm not really sure what you are trying to describe?
(And I'm not sure what the B1 C78 551 OFF B51 10^ profiles are?)

But, having less than perfect RGB Separation after calibration is expected if the display has underlying issues.
That is explained in the User Guides.
The monitor also has Blue Blacks by default, and as per the user guides you cannot correct near black/black unless you deliberately raise the black level.
And talking of black levels, I would want to know why the display shows black as being over 0,1 nits - that is far too high.

(And you have ZRO under your user name as you have not posted many times - it has nothing to do with your software license.)

Steve
Steve Shaw
Mob Boss at Light Illusion

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 Calibration Signal Chain (Rec. 709) Resolve - Decklink - BMD 12G 3D LUT // Data vs Legal Levels

 

 
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