Stu Maschwitz wrote an interesting article on Extended Dynamic Range, or how Apple brings High Dynamic Range to non-HDR displays. This doesn’t just refer to its Pro Display XDR; it’s how iPhone OLED displays can be defined as HDR.
So Apple has a method of showing HDR and SDR content together on the same screen. It works on every display Apple bills as “HDR,” even though the phones are performing the stunt using a different underlying technology than the 30″ Mac display. The XDR uses “local dimming” to light up an array of LEDs brighter behind the HDR pixels, as needed. The OLED displays drive each pixel to the desired brightness individually.
Check It Out: How Apple Brings HDR to Non-HDR Displays