We used the following settings to calibrate the LG UH8500. If you intend to play video games on this TV, make sure to copy those settings under the 'Game' picture mode as well.
Start by selecting 'Expert (Dark Room)' picture mode, which is the closest to the look we want to achieve with our calibration. We used a 'Backlight' value of 28 in our totally dark room, but you should select whatever value works best for your taste, and for the lightning conditions of your room.
To remove any unwanted artifacts caused by over-sharpening, set 'H Sharpness' and 'V Sharpness' to 0.
For most content, leave 'Color Gamut' set to 'Normal'. 'Wide' will over-saturate the colors, making video look wrong if the content isn't made to benefit from the feature. For cartoons, 'Wide' will usually look good.
To activate chroma 4:4:4 for sharper text when using the TV as a PC monitor in 4k @ 60Hz, enable 'HDMI ULTRA Deep Color.'
The following are the results of the white balance and colorspace calibration on our unit. They are provided for reference, and should not be copied as the calibration values vary per individual unit even for the same model and same size as the TV we reviewed due to manufacturing tolerances. If you want to try them you will need to enter all values shown, as all of them are active at the same time. If you end up with worse picture quality, simply reset them to the default values.