Notes on this Rant
To be clear, I created a straw man by taking a beautiful movie, Sicario, and coarsely applying the only area of “improvement” that HDR allows: brighter highlights. This was only possible because Sicario doesn't even use the entire dynamic range of HD video. The filmmaker’s intended look fits entirely within the low-dynamic-range container of HD Rec709. It’s a low-contrast, low-saturation film. The “HDR” 4k version is no different, and seemingly enjoys only the benefit of enhanced color fidelity and resolution in the 4k Blu-ray edition. Those are real benefits. And there are movies with bright, poppy colors that would happily occupy the greater dynamic range of an HDR TV. And working to that standard, a filmmaker would, of course, still be welcome to opt out of the brighter highlights, and choose their own dynamic range “box” to work within.
...in practice, that won’t be the case. Because even without HDR, TVs already ruin movies by trying to make them look “better.” HDR is just another axis for your relatives’ TV to be set up wrong. And just like modern TVs try to “fix” 24p with motion smoothing, you can bet they’ll also offer all kinds of delightful modes to “HDR-ify” your LDR content. And if you think that will look better than my coarse examples above, you haven’t seen how bad TVs already are.
HDR has the potential to be a useful tool. But TV manufacturers will absolutely screw it up.
Follow Up 2017-04-21: All the Ways I’m Wrong
There’s been a lot of great response to this post, and some thoughtful disagreements. I opened the door for the disagreements by structuring my argument rather sloppily; conflating two different ideas.
Argument 1: I’m not personally Interested in the Creative Potential of HDR for Cinematic Images
I can’t be “wrong” about this one, because it’s my opinion, but of course you are welcome to disagree.
When I took the intentionally, creatively LDR images from Sicario and brightened up their highlights, I wasn’t saying that your HDR TV will do this to Sicario. Nor was I saying that an mastered-to-HDR-standards version of Sicario would look like that.
What I was saying is the good old Prolost argument that less is more with cinema. Sicario is widely regarded as a very beautiful film. It intentionally uses a very low dynamic range, less than even Rec709 allows. The only way the HDR-ness of HDR can “improve” that is if some idiot tried to brighten up the highlights. What I was trying to show is that the flagship feature of HDR has nothing to offer Sicario.
But I mixed that argument in with my distrust of consumer television manufacturers, which opened my up to rebuttals like this: