My Apple TV 4 (ATV4) hooked up to a 4K TV looked like everything was filmed thru fog. “Shot through scrim” as they say. No contrast, no vibrancy.

Well, looking around, as you likely have, this is hardly uncommon.

I tried the whole range of adjustment, (as you likely have) without any luck.

Last night I figured out what it was.

Now, I’m not saying this will fix yours, but I -am- pretty sure that this is at least the gist of the problem, and perhaps armed with that, you can apply this to your particular setup.

My setup runs the ATV4 in to a Sony AV amp and out to the input HDMI on my TV. This allows me easy switching of my Tivo, ATV4, DVD player and Xbox.

The issue is HDMI itself, and how Apple vs your TV (vs your AV unit if you have one) implements it. HDMI is (at least in part) the industry’s attempt to keep you from playing pirated video (among other “safeguards”.) To this end, it isn’t a “simple pipe” of the audio/video signals, but a sophisticated chit-chat, where one component talks to the other and even coordinates how things will work.

Well, when that coordination isn’t just right, you end up with famous foggy picture: no contrast; washed out color etc.

My amp has a buried setting for each HDMI input. (I’m suggesting here that your TV may have this too, so keep reading.)

My amp had a setting for “standard” HMDI input, and “enhanced” input (ie 4K/HDR). If memory serves, my setting was, in fact, “enhanced.” But I decided to check the inputs for my other devices, and did find one set for “standard.”

What all this mucking about did however was this: it lead me to go to the HDMI input for my ATV4, and toggle it; to switch it to “standard” and back again to “enhanced.” When I did that, the TV screen went black and then came back…

… in Glorious Color! The fog was gone!

So that toggle caused  the “chit chat” between devices to start over, and reset things properly. THAT is what I discovered, and which I hope will apply to you as well. See if your AV-amp has similar settings. If you don’t have an AV-amp in the circuit, and you’re going from your ATV4 right to the TV, then see if you TV has an HDMI setting that makes a distinction between the quality/type of incoming signal (my “standard” vs “enhanced”.)

In fact, some TVs have a single specially marked HDMI input for HDR/4K.

Finally, before you do all this, here’s the other important thing I learned: mucking about with the ATV4 settings breaks this delicate balance, so set your ATV -first- and then leave it alone.

The new OS allows you to choose “automatic dynamic range” or “original dynamic range” (aka “as shot’.) Choose the latter. Do NOT choose automatic range. Then quit messing with it.

NOW you can try what I’ve described above:
1) setup your ATV4 and leave it alone.
2) if you have it, set your amp or tv to “enhanced” (or the equivalent) mode for that input. (Perhaps that means choosing the “enhanced” input for your cable. )
3) Do what it takes to “toggle” that so the devices are forced to reset their communications. (Unplugging and replugging it? I dunno, that’s not how mine works, so I can’t testify to that bit.)

I’m no guru on this stuff, and don’t blame me if you try this and your TV vanishes in a puff of smoke…I’m just sharing what worked for me, and why I think it worked.

Good luck to you!