I'm one of the almost very happy owners of LG C8. One issue that making me mad is this black level issue on Dolby Vision.
I was really pissed reading all of that comments, that suggested that is HDMI only issue. Obviously is not, as i see elevated blacks on every Netflix show in interal app (does anyone know any Dolby Vision show with really pure black levels? i don't)... I haven't seen similar issues on HDR10 content. Obviously the letter box bars were fine, but not the blacks. Issue was clearly see on almost all end credits i've checked - most notably on MindHunter end credits, or at the beginning of Bright.
I thought i first i could fix that by lowering the brightness to 49. Well, that "fixes" that issue, but at what cost? We're loosing so much shadow details, that this couldn't be a viable solution (btw, why we get 1-100 point scale of brigthness, where even 1 point make such a big difference?).
My my TVss cinema and gaming profiles were professionaly calibrated by best polish calibrator. I phoned him and ask him what is going on with this Dolby Vision. He told me that he knows this issue and it's because this content has been mastered this way and what only i could do is to lower the brightness by one point (by the cost of loosing shadow detail). I was furious. I actually bought this TV because of good Dolby Vision implementation. I paid for professional calibration of it and i still had the incorrrect image and everybody said nothing can be done on this topic.
Reading this topic didn't help at all... No ideas on fixing this - a lot of people just checking if letterbox bars are greyed not checking the actual content of the image.
Today i installed new software 04.10.15 on LG C8. First thing i've checked was of course raised black levels on Dolby Vision. Unfortunately, new software changes nothing on this matter.
So i was planning to come here and share my sorrow my pain with you guys, but before writing i decided to test all possible settings.
First i've checked all the additional options in the menus (noise reductors, super resolution, tru motion etc) which are turned off always. Nothing helped.
Then i've checked OLED light - lowering it did not helped. And we don't want to do that anyway...
Brightness changes are no go obviously...
Then Sharpness - it was really strange because after applying like 20 or 25 on this grey black dissapeared but strange line at the top appeared. So it was somehow affected by processing of the TV! I reverted the sharpness settings and tried the contrast.
I just dropped contrast from 100 to 99 and... IT WORKS! I really couldn't believe it. I've searched whole internet for the solution, and nobody mentioned that. It's not that we get perfect black then, but is really really good, almost perfect. From reasonable viewing distance it's black (2m for 65 inch for me) and lowering contrast further doesn't change anything. If it works on Mindhunter end credits i assume it should work everywhere. I will try to test a lot of troublesome scenes as well as normal viewing scenes to check how this particular change affects the image, but from what i found so far i could't find any difference on naked eye with normal viewing, but it fixes almost perfectly all the near black issues i had with DV.
To summarize: LG C8, Internal LG Netflix app, latest software 04.10.15, Dolby Vision Cinema profile, drop contrast from 100 to 99 and let me know, if that somehow mitigates this issue for you and what's the impact on the image. Try also with the external devices if possible.