When you calibrate a TCL TV if you use the local dimming function should you calibrate with it on or off. The reason I ask is because I thought it was standard practice to turn off local dimming while calibrating then enable it again after. But after enabling it again it seems to mess with the underlying calibration which is probably too be expected but it makes the image look wrong.

There is no real answer or right/wrong for that.
It is really down to the user's preference.
But if the resulting image looks wrong one way, that would suggest the alternative approach is needed.

Personally, I always calibrare with the same modes/settings as will be used for final image viewing.

Steve

It turns out it's TCLs poor local dimming algorithm as it happens without calibration as well. I am not sure if it's the newer firmware caused it or not but certain shares of colour get a green hue with local dimming turned on and it goes away when you turn it off. Its not even possible to report this bug to TCL though because they always say contact the seller you bought it off.

Not sure that makes sense, as any local dimming is altering the backlight zones, which are monochromatic
And any LUT would alter the 'colour' component at the given backlight value regardless.
You likely need to define the input stimulus value that shows the issue to then define where is sits in a full profile.

Feel free to send me your pre-calibration profile, the LUT, and the verification profile.

Steve

I will when I look at it again but all I know is it's not there when local dimming is turned off so I believe that there may be an issue in the TVs firmware.

Thanks for helping me.

I have a question do the # lines need to be removed from the SDR 1DLUT files as well as it's mentioned to do it for HDR HLG and Dolby Vision but no mention of SDR. Also I didn't realise it meant from inside the file so I didn't do it could that be the problem? Although the above mentioned problem is affecting all picture modes calibrated or not calibrated so I guess not?

Another thing I don't get is when I do the 1DLUT first do I upload this to the TV first then do the second pass for the 3DLUT or should it be selected as an Active LUT in ColourSpace and will that work when using PGenerator or will ColourSpace only use this when creating the 3DLUT.

The # lines need to be removed from any 1D LUT - as the User Guide states.
"Note: Presently for 1D LUTs the # information lines in the file header needs to be manually removed."

And the User Guide also defines the use of the 1D LUTs.
"When using both the 1D and 3D LUTs in combination, the 1D LUT can be used to pre-set the TV's greyscale and/or gamma as a first pass, and then the TV can be re-profiled with the 1D LUT active, and the 3D LUT generated from the second profile pass uploaded to the 3D LUT option for the final gamut calibration. The 3x3 Matrix should be left as a null upload, as performed before profiling."

Steve

Yes I read that but does it mean as an active LUT within ColourSpace or uploaded to the TV. The reason I ask is that the filename has POST1D and the guide says

"There are two LUT slots available for SDR and HLG calibration, with the 3D LUT used in isolation being the normal configuration to use for display calibration, although the 1D LUT, which is after the 3D LUT, can also be used for calibration if required."

This suggests that the 1DLUT should be uploaded after the 3DLUT. So does this mean I can't use the 1DLUT as a shaper LUT.

Thanks

Oh, I see what you mean...
But, if the words 'Active LUTs' are not used, it means Uploaded.
Technically, it would make no sense to do the workflow as defined using 'Active LUT', as the 1D would then be negated when the 3D LUT is used in the TV, as the 1D will never have uploaded been in the TV, but would have been used in the generation of the 3D LUT.
(I guess this is an example where we tend to assume a leve of calibration knowledge.)

And no, as the 1D LUT is stated as being After the 3D, it cannot be used as a Shaper LUT.
And must be uploaded first, before profiling for the 3D LUT.

Steve

Ok thank you and do you recommend using 8 bit or 10 bit when profiling.

That's up to you...

Steve

What is the correct way to make a 1DLUT the way I did it was profile a grey scale large and then use the LUT generator selecting REC709 as the source and the profile as the destination. I used the Hybrid method and then created it and exported it with the 1tcl LUT. The reason I ask is because when I uploaded the unity bypass LUT the weird greenish hue that is sometime there is gone but when I upload the 1DLUT that's when it appears but only when local dimming is on. Its the same on all picture modes as well so I think local dimming must be broken because it looks good 90% of the time but then it sometimes appears on certain colours. When I get chance I will upload a verification profile for you to look at.

You can make the 1D LUT in any way you choose.
But as with all LUT, Peak Chroma is the usual method, unless there are issue with the display that mean the other options become more suitable.
That is explained in the User Guides.

As said, you need to define the colour that causes the issue, and assess why that is happening.
And I really can't make any specific suggestions unless you provide the pre-calibration profile, the LUT, and a verification profile.

Steve

Ok so I think the issue is the local dimming algorithm is altering the black level and it may not be fixable as I managed to get rid of it by significantly turning it up til black became quite a very light grey going from a setting off 48 to about 90 so I'm not sure if it can be fixed reasonably.