LG G5 3D LUT Upload doesn't match Active LUT?

Hello,

Whenever I upload a LUT to the 3D slot in my G5, it seems to not match what I get when using the same LUT in Active LUT, in a visually obvious way. Measurement wise, I'll see changes, but the greyscale seems only slightly affected by it. If I upload the same LUT to the 1D slot and put the 3D LUT back to Unity Bypass, it looks and measures exactly the same on the greyscale as if I were using Active LUT.

It was my understanding from reading the guides on this site that I should be able to only upload a 3D LUT and accomplish full calibration with greyscale included and I can leave 1D on Unity Bypass. Would anyone have any pointers for what I might be doing wrong? It almost seems like the TV is not reading the 3D LUT correctly, but I've seen other posts of people calibrating their G5's with 3D LUTs seemingly without issue, though I've run out of ideas on what I could be doing wrong.

There are a number of possible/probable reasons.
Most 3D LUTs have a coarser granularity than the 1D, which is why using Lage LUT sizes in ColourSpace works well when the 1D is treated separately to the 3D.
https://lightillusion.com/lut_size.html
Alternatively you may have a range mismatch - Legal vs Data ranges.
https://lightillusion.com/data_legal_levels.html
https://lightillusion.com/issues_lut_processing.html
https://lightillusion.com/issues_signal_processing.html
https://lightillusion.com/issues_signal_range.html

Steve

Hey Steve. Thank you for the response. I will review all of those, I think I hadn't seen one or two of them. I'm stuck on the smaller LUT size with HTL, but I at least don't think it's a legal vs data range thing. At one point I tried using the Video Scale feature in the LUT generator; it was pretty much the same story. Uploading that to the 1D LUT slot produced an obvious change reflecting the change in scale, with the display having an elevated black level afterwards, and very little effect to the greyscale when uploading to the 3D LUT.

The LGTV Integration Guide says:
"Note: Due to some LG firmware issues, it may be necessary to switch to a different picture mode and back again, or even power down the TV, and unplug for a while, to activate the uploaded LUT.
Also verify the correct settings for the LUT upload, such as Colour Space, etc."

In fact, I had to unplug the TV to get it to work properly.