High dynamic range widens the gap between the brightest and darkest thing a screen can show at the same moment. That gap is a contrast problem before it is a brightness problem, which is why two displays quoting the same nit figure can look nothing alike.

Almost every monitor sold now carries an HDR label of some kind. VESA's DisplayHDR programme exists to separate them, setting measured floors for peak luminance, black level, colour volume and how the backlight is controlled.

The sections below explain what each certification level demands, how mini-LED and OLED arrive at contrast from opposite directions, and how to set the whole thing up in Windows so the desktop does not end up looking worse than before.