Read on Twitter
Telephoke, n. Legit boke from a telephone.
The HDR display on the iPhone 12 Pro Max is wild. It happily shows brighter-than-white pixels alongside the UI “white.”
Screenshots don’t capture the overbrights, just like macOS on the Pro Display XDR. What a stunt it is to show an HDR thumbnail against Finder “white.”
After noticing that my iPhone 12 Pro Max and my Pro Display XDR happily display HDR values in an SDR context, I have since discovered that the same thing happens on my iMac Pro and 16" MBP, neither of which claims to have an HDR display. How is no one talking about this?
This is the exact same demo as in the previous tweet in the thread, but on my iMac from 2017. Apple has quietly added HDR display capabilities to devices that long predate the Pro Display XDR, and I cannot find a single bit of information about this.
On the XDR, the HDR values appear instantly. On the older Macs, they fade into view in a few choppy steps, as seen here.
Of course, it’s very hard to see this in an SDR video shot off the screen. In person, the effect is downright eerie. A tiny window in a screen you've owned for three years is suddenly, magically, brighter than the 255 “white” pixels surrounding it.
Is your Mac overdriving your LED backlight and mapping 255 white to some gray value, just on the off chance that some HDR pixels come along to occupy that headroom?
Update: Yes, and Apple calls it EDR. More as I uncover more.
Here's a page with some info. As I went to screenshot part of it on my iMac, I noticed that the screenshot crop displayed in EDR (visually brighter than the 255 white page). How meta.
https://developer.apple.com/documentation/metal/drawable_objects/displaying_hdr_content_in_a_metal_layer/performing_your_own_tone_mapping
https://developer.apple.com/documentation/metal/drawable_objects/displaying_hdr_content_in_a_metal_layer/performing_your_own_tone_mapping
Some more digging and a phone call with an Apple friend later, I came up with some answers about EDR — and of course, some opinions. https://prolost.com/blog/edr
