Hi all, I am using Resolve video levels > Blackmagic Studio Monitor > HDMI > Atomos Ninja V with video levels. Using Colourspace LTE with an i1 Display Pro OEM.

I did a 13-point cube calibration and probe matched to an i1 Pro 3. I noticed when I extracted the color space from that profile that the EOTF is ~2.2, despite the Ninja V being set to 2.4. In conjunction with the attached CIE graph showing the monitor profiled to itself as the Target, is this just a sign of a poor monitor?

I also was getting an EOTF of ~2.2 with a SmallHD 702Bright that was supposedly set to 2.4

Thanks

LUT generated from the probe matched 13 point prof

Extracted space from 13 point profile showing 2.2

Extracted the color space and set as target

You will need to post the pre-calibration profile, and the verification profile.
Can tell nothing from the screen grabs.

You can also see the EOTF value in Manual Measure, as well as see the curve in the EOTF graphs.

Steve

Sorry about that. I certainly went wrong somewhere, I loaded the LUT into the monitor and did a 512-patch profile, which came out terrible. I did read the user guide and saw that just loading the LUT and profiling isn't a great method to verify.

Attached file: Pre-calibration and verification

Ok - the pre-calibration shows the display can't accurately do Rec709 gamut, and the EOTF is approx. 2.2.
Obviously the displays is not a critical colour capable one.

After calibration there looks to not be the same probe matching applied, as the gamut has shifted outside the pre-calibration gamut, which is not actually possible...
(See the Red gamut area, and the Library shows no 'Match' is active on the saved profile.)
But, the EOTF is now approx. 2.4.

I assume this is for outside, on-set use, as the peak at 500+ nits is very high, and is making the blacks lift to 0.9 nits.

Steve

Thanks Steve, so sounds like it is a bit of "we get what we pay for". It is an on-camera / outside monitor so I did set the nits quite high. I'll troubleshoot the verification again.

Thanks

The big issue is the display has a very poor, and inaccurate, response in Green.
That meant the LUT generation is struggling.
(Also, make sure you have enough Extra Delay set if you are using Resolve as the TPG.)
It actually also looks like the displays is pre-calibrated badly to Rec709, as there is gamut compression at the gamut edges.
So the issue is really with the pre-calibration display setup...

Steve

Thanks. I did auto Extra Delay and it set it to 0.04; I'll up it a bit and keep evaluating my pre-calibration chain. I have a 1 second increment time.

The Ninja V is not a reference monitor and is only going to give you a preview of the content.

The LUT function is designed for creative look LUTs (user guide) and not for a correction LUT, this is because the colour pipeline is going to be transforming the input to the look based on an internal calibration LUT. You can improve the output by using the Atomos calibration here which will update the internal calibration LUT, however, it is still only going to provide you with preview quality.

Hope that helps explain why this is not working.

EricCT

Use 0.75 sec extra delay if you are using Resolve iTPG.

Send YCbCr (Video Level and LEGAL/8-bit in ColourSpace) signal to the monitor, since the cine cameras are using that signaling.

Upload a reset 3D LUT to the Atomos before taking the profiling measurements.

Use FitSpace during LUT generation.

I don't know if the LUT will require a level scaling filter to apply, it has to do with Atomos video pipeline/processing.

Perform a quick verification with grayscale and saturation sweep.

Apply a videoscale pass black filter before the LUT export and upload that second LUT to Atomos.

Verify again with grayscale and saturation sweep, and compare the results with the first LUT verification ...so you will know if you need to apply videoscale pass black filter or not.

With that being the case, the best option would be to use the Atomos calibration software (which is the crappy X-Rite stuff re-branded) to disable the calibration. That should be possible by altering the target colour space the native gamut of the display.
You can then use the Look LUT as the calibration LUT.

Steve

Thanks for the follow-ups and additional tips. The monitors I was attempting are indeed just on-camera monitors and not reference monitors. I'm just looking to get the on-camera monitors better than they currently are. The closest monitor I have to a reference monitor is SmallHD's 2403 Production monitor. I probably bit off more than I can chew by trying to start with monitors that aren't quite meant for this rather than a very linear monitor like FSI.

This has been the adage: can read 100 books about baking bread, but until you bake 1 loaf yourself you really never learn.


I have attempted that in the past but it does a pretty poor job, if their software even "finds" the monitor when it's hooked up to the computer.

Thanks again!

Hi, attached is a before and after profile. No probe matching. The LUT was generated with Fit Space. I tested with videoscale black pass but the delta-e was a little higher with that. In the verification profile the gamut is outside of Rec709, even though the LUT was generated with Fit Space, which means the LUT was generated with bad profiling data?

Attached file: Before and Verification profiles

The pre-calibration profile shows, as before, that the display is badly pre-calibrated to Rec709.
There is a really bad overall colour shift, as seen with the Tangent Lines...
The post calibration is far better, and the slight over-gamut near red is likely due to no probe-matching.
You would have to test to verify that.

Steve

Pre Calibration

Red Gamut Error

Thanks Steve, once I purchase Colourspace I'll be able to truly verify it's reading at video levels. The chain is setup that way but I'm not 100% confident the monitor is behaving as it should.

Thanks for all the support.

Eric