Display Calibration

[Nastenka]

Hello, I had a couple questions regarding the 3DLUTs created by DisplayCal.

- According to and following the various and official tutorials on how to create a madVR 3DLUT, during the workflow to create a madVR 3DLUT near the end madTPG should pop up and carry out further measurements. However, for me the 3DLUT is created after DisplayCal is done measuring, and while madTPG is launched, nothing is shown there or measured. Is this normal?

- I have profiled and created 3DLUTs for two monitors, however, when DisplayCal saves those 3DLUTs in its default location, it's called BT.709 for every monitor. This will lead to the files overwriting each other when profiling one after the other. I've furthermore noticed that the file sizes for different monitors are exactly the same, 96 MiB. I had the same question as above, have I set something wrong in the calibration options? I meticuously followed the official tutorial.

Thanks so much.

[huhn]

- According to and following the various and official tutorials on how to create a madVR 3DLUT, during the workflow to create a madVR 3DLUT near the end madTPG should pop up and carry out further measurements. However, for me the 3DLUT is created after DisplayCal is done measuring, and while madTPG is launched, nothing is shown there or measured. Is this normal?

this can be normal. you can verify it manually.

- I have profiled and created 3DLUTs for two monitors, however, when DisplayCal saves those 3DLUTs in its default location, it's called BT.709 for every monitor. This will lead to the files overwriting each other when profiling one after the other. I've furthermore noticed that the file sizes for different monitors are exactly the same, 96 MiB. I had the same question as above, have I set something wrong in the calibration options? I meticuously followed the official tutorial.

the same file size is normal and the overwritng too is a result from making displaycal easier to use. i totally gave up on the "easy" way and do it manual now.

you can create a new 3d with a custom name and your old readings using a tool called 3dLUT maker it's part of displaycal GUI.

[Nastenka]

Thank you for your response. It looks like everything might be alright after all. I tried the 3DLUT Maker, but wasn't sure if it would do the same as unchecking "Create 3DLUT after profiling".

[huhn]

it is the same program but it let you save the 3d LUt with it own name.

if you don't have 2 different 3dLUTs than you are not fine.

[Nastenka]

I've had a look at the 3DLut Maker, but it differs from the old method I used in that I can now choose gamma for Rec.1886, the default is 2.4 with my profile loaded.
During the regular calibration process however, I originally chose a Tone curve of 2.2.
Should I adjust the Rec.1886 gamma for the 3DLUT to 2.2 accordingly or should I go with 2.4 nonetheless?

[huhn]

it doesn't matter what you choice before you are just reading your screen the 3d LUT will use a source profile like bt 709 and map that to the readings of your screen.

or in short just select the gamma you want.

[Asmodian]

Simply agreeing with huhn.

If you can change options on your screen to more closely match your desired output, before profiling, you might get slightly better results but changing settings during profiling will not make a difference.

I don't think the color patches used for profiling change at all when changing options like gamut and gamma. At least I did some testing with my TV (LG OLED C7P) and I seem to get identical results (within my measurement variability) if I select either DCI-P3 / BT.709 or 2.20 / BT.1886 when profiling using Calman 2017 (the TV was always in the same mode, P3 BT.1886) and creating a BT.709 or BT.2020 3DLUT. Profiling is simply making a map of color value sent v.s. the color displayed so it makes sense that there aren't any options that affect the results. We are mapping the pure native RGB color space of the panel.

[Nastenka]

Thanks you two for your input. Left it on 2.4.

[Arm3nian]

Originally Posted by Asmodian

No, DCI-P3 is bigger than Adobe

If so, why does Displaycal report the gamut volume of DCI-P3 as larger than Adobe RGB?

[huhn]

except for the bigger or larger word both you say the same not?

[Arm3nian]

I'm trying to measure HDR peak brightness to create a 3D LUT, but need some help to load a test pattern. I use HCFR and set the reference to UHDTV DCIP3 and the gamma to 2048. I set the generator to madTPG. The problem is the white it displays isn't white, it's a dark gray?

To get my TV to switch into HDR mode I start an UHD bluray and go fullscreen. It would be nice to skip this step entirely but I don't know if that's possible without madVR.

[Asmodian]

There is a button in madTPG to enable HDR so you shouldn't need to launch a UHD video to switch to HDR. Have you used it? This was all I needed to measure my displays peak white in HDR.

[Arm3nian]

The button does not do anything, with or without a test pattern. Also, when I switch by playing a movie, and measure a white, it's just the peak brightness of a non HDR white. I feel a test pattern with HDR metadata has to be sent for it to switch, and for it to actually display using HDR.

[Asmodian]

To get HDR to trigger with the newest Nvidia drivers (417.35) I need to set madVR to use FSE and output 10 bit as well as madTPG set to full screen. When I do this the 255,255,255 pattern from HCFR is at my HDR's peak white.

[Arm3nian]

I was on the previous drivers (416) when I received my TV. Updating to 417 changed nothing for me. Both windowed and FSE still trigger 12 bit HDR output in madVR. The button did nothing on 416 or 417 however. If I switch using madVR, and then output white in HCFR with madTPG fullscreen, it does give me the peak white.

I did this the other day though using some test patterns I found on avs. The TV sustains ~1930. After setting the optimal settings and adjusting the white point it drops to 1597 sustained. So I should use this in the 3DLUT menu as target peak luminance? The madVR HDR preset doesn't calibrate the gamma, only the whitepoint. So I was thinking to skip it all together, adjust it to 6500k manually using the RGB gain sliders, and just profile. The TV has gamma settings as well, if I really wanted to I could adjust that, but it's quite a bit of work.

[Damien147]

How do you guys adjust backlight on your TV?Is there a standard in cd/m^2 or it's personal preference?

[Asmodian]

It is personal preference, and the ideal level depends on the light level in the room. I use 100 cd/m² for a dark room.

The SDR calibration guidelines suggest between 80-160 cd/m².

[Damien147]

I was with 200 cd/m² these days for night and day.I am gonna try close to 160 then.Thank you.

[chros]

Originally Posted by Damien147

I was with 200 cd/m² these days for night and day.I am gonna try close to 160 then.Thank you.

There was a THX value back in the day (105 nits, in theatres), but due to lot of complaints (too dark) they raised it to 115-120 nits. That is for night usage.
I use:
- night: ~120 nits with 2.4 gamma
- day: ~140 nits with 2.2 gamma
Hence I had to create 2 3dluts and change them (with hardlinks in a script).

But you have to be aware that when you increase the blacklight of most of the displays (that doesn't have perfect black) the black level will also be raised (that's not a good thing).

[Damien147]

edit:I am a noob and for 2 years I got used to setting the backlight full.
I am gonna try your settings but from what I can understand it needs some time to get used to it.Thank you both.