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Hi,
My plasma is a complicated beast and none of it’s controls seem to work well. So what I’d like to do is leave the thing in it’s native state and correct the white point and control luminance via a 3dlut (for MadVR). In order to have Displaycal correct the white point, do I just leave ‘whitepoint’ on the calibration tab as ‘chromaticity coordinates’, or do I have to change this to ‘color temperature’? And for white level I just change this from ‘as measured’ to ‘custom’? Do either of these changes necessitate 1dlut calibration prior to 3dlut?
Hi,
In order to have Displaycal correct the white point, do I just leave ‘whitepoint’ on the calibration tab as ‘chromaticity coordinates’, or do I have to change this to ‘color temperature’?
No, the correct choice is “As measured” on the calibration tab. That way, all the whitepoint correction will be done by the 3D LUT (rendering intent needs to be absolute colorimetric with whitepoint scaling).
Thanks – if i set it to as measured how does it know i want 6500k? Or does it assume that i do? Also, am i correct in just changing the whit level to custom and changing the value there to what i want, eg 135cd/m2?
if i set it to as measured how does it know i want 6500k?
From the source colorspace selection on the 3D LUT tab – Rec 709 is 6500K.
Also, am i correct in just changing the whit level to custom and changing the value there to what i want, eg 135cd/m2?
I would recommend not setting a white level target so that you can keep the full native contrast ratio – instead, use interactive display adjustment to adjust your Plasma to 135cd/m2.
Thanks for the advice. I am a little confused about something. I ran a greyscale sweep with hcfr to see how it looks and see how gamma is tracking. There were some problem areas in the greyscale of course but gamma tracked very closely to the dotted line (2.4 with 1% input offset in preferences), except ire70 and up which were a bit all over the place. I just ran a calibration with displaycal with 2.4 relative 99% output offset, thinking this should look pretty much the same as as what i saw with hcfr as it was close to the target anyway overall but to my surprise the image is much much brighter. I was expecting gamma to look pretty much the same as what i saw with hcfr, which means gamma shouldnt have changed very much with the 3dlut. How can i achieve this? The same window size and background was used.
I ran a greyscale sweep with hcfr […] gamma tracked very closely to the dotted line (2.4 with 1% input offset in preferences) […]. I just ran a calibration with displaycal with 2.4 relative 99% output offset, thinking this should look pretty much the same
I would expect those settings to be equivalent as well.
Did you enable white level drift compensation? This is recommended for plasma due to ABL.
The same window size and background was used.
How big was the pattern area? Small sizes (5-10%) with a background of 20% APL linear light should work well with plasma if I recall correctly.
White drift was enabled. I actually used 8% window with 40% linear light background as suggested on AVSForum. I’ve tried gamma light but with no success, looked awful. I’ve also tried standard 10% windows with similar bad results. The results are better with linear light.
I changed absolute to relative on the 3dlut page and it looks much closer to what I saw with HCFR. However, there are still some mysterious differences. With HCFR gamma tracks almost perfectly with the line up til 70% or so then goes a little crazy. But the lower regions 5%, 10%, 15% are bang on that line (2.4 1%). If I set Displaycal to 2.4 99% bar 17 flashes just as bright as with no 3dlut, however bar 18 is smaller than bar 17. I have to lower output offset to 90% to get things at that end looking the same as without the 3dlut. But that is brightening the image too much, and shadows in particular looked much more washed out. I just don’t understand why the difference, when I used exactly the same window size and background.
This was just the default 1500 patches. I guess i could try a shorter run.
This is probably a silly question but is there a way to have a target gamma of ‘as measured’? So displaycal would do a full gamma sweep and map the 3dlut accordingly?
This is probably a silly question but is there a way to have a target gamma of ‘as measured’?
No, that is not possible easily. Tone and color response are not separate things and are inherently intertwined in the measurements. With a lot of fiddling on the command line, you could probably create a synthetic profile with Rec. 709 primaries and the same TRC as your plasma, which could be used as source for the standalone 3D LUT maker. But I doubt it’ll help with the problems you’re having.
If you attach your current profile for the plasma, I’ll look at wether or not the device response seems sane.
If you have the profile selected under “Settings”, you can click the small archive button next to it to create a compressed archive (do not include the 3D LUT).
Gotcha, thanks. I just did that and it’s 27.5mb which exceeds the limit. Is there anything specific from that archive you’d want?
