HDR Files, Ordinary Screens
A photograph that holds the sun and the shade at the same time has to give something up on the way to your desktop.
HDR is a promise about range. The file keeps detail in the brightest edge of a cloud and in the shadow under a pier at once, either because the camera bracketed several exposures or because the sensor could hold both ends in one frame. What ends up stored is more light than a normal panel was ever built to show.
On an SDR screen that surplus has to be folded down, and the fold is called tone mapping. Done carefully, the highlights keep their shape and the shadows stay open. Done carelessly, the same picture arrives flat and grey, or the sky clips to paper white with nothing left inside it. This is why an HDR wallpaper can look worse than a plain one on the same desk.
So the useful question for a wallpaper is not how much range the file claims, but how much survives the fold. A frame that already reads at a glance in SDR will read on any monitor you move it to; one that depends on a bright panel to be legible spends most of its life looking disappointed. The screen shows only what it can show. The file just decides how gracefully it loses the rest.
