HDR vs SDR
The difference is one thing, not fifteen. SDR puts a ceiling over the picture: nothing can be brighter than white. HDR removes it — highlights are allowed to exceed white, and the file says by how much. Everything else on every comparison list follows from that.
The ceiling
In an SDR image, a desk lamp, a car headlight and the sun are all the same value: white, full stop. The picture was graded against a reference where white means 100 nits, and however bright your screen goes, the brightest thing in the image can only ever be as bright as a white pixel — a blank document glows exactly as hard as a sunset.
HDR stores where the image should exceed that. The encoding reaches 10,000 nits; real screens manage somewhere between 400 and 4,000, and the display maps what the file asks for onto what the panel can do. The result is not a brighter picture overall — midtones stay put — it is a picture in which the few genuinely bright things are allowed to look bright.
The rest of the specification exists to support that range. Eight bits per channel is enough for SDR; stretched across HDR’s range it would band a clear sky, so HDR is 10-bit. And the colour gamut usually widens at the same time, because the same displays that go brighter also reach deeper reds and greens.
Side by side
| SDR | HDR | |
|---|---|---|
| Peak brightness | Graded to a reference white of 100 nits. Your screen may show it brighter, but the picture holds nothing beyond white. | The PQ curve encodes up to 10,000 nits. Real screens deliver 400–4,000, and the picture knows which parts should use it. |
| Bits per channel | 8 bits — 256 steps. Enough for the SDR range. | 10 bits minimum — 1,024 steps. Stretching 8 bits over the wider range would band the sky. |
| Colour | Rec.709 — the HD television gamut, unchanged since the 1990s. | Usually P3 inside a Rec.2020 container: deeper reds and greens, not just brighter ones. |
| On a screen without it | Exactly as intended. | Tone-mapped down, or — for gain-map photos — the SDR base image shows and nothing is lost. |
Every comparison image is fake
This page is SDR. So is every article comparing the two — which means every side-by-side “HDR vs SDR” picture you have ever seen was produced by dimming and greying the half labelled SDR. A medium with a ceiling cannot show you what removing the ceiling looks like.
The honest demonstration is an HDR file of your own, on your own screen. Our SDR-to-HDR converter makes one from any photo — a model predicts which highlights should glow and writes the result as a gain-map JPEG or AVIF, entirely on your device. On an HDR screen the highlights lift off the page; on any other screen you simply see your original photo, because that is what a gain-map file degrades to.
Questions people actually ask
What is the difference between HDR and SDR?
One thing: the ceiling. In SDR nothing in the picture can be brighter than white — a lamp, the sun and a sheet of paper all top out at the same value. HDR removes that ceiling: highlights are allowed to go brighter than white, and the file records how much brighter each part should be. The deeper colour and 10-bit precision that come along exist to support that range without artefacts.
Is HDR better than SDR?
On a screen that can genuinely go bright, yes — a sunset or stage lighting in real HDR is not subtle. On a panel that claims HDR at 300 nits with no local dimming, the label is marketing: it accepts the signal, cannot show the range, and often looks dimmer than its own SDR mode. The format is better; not every screen wearing the badge is.
Why does HDR look washed out on my monitor?
Almost always Windows, not the monitor: with HDR on, ordinary SDR content — the desktop, the browser — is composited into the HDR signal at a default brightness that reads grey and flat. Raising the "SDR content brightness" slider in HDR settings fixes most of it. The rest is panels that accept HDR input without the hardware to show it.
What are HDR10, Dolby Vision and HLG?
Delivery formats for the same idea. HDR10 sets one brightness description for the whole film; Dolby Vision and HDR10+ adjust it scene by scene, which mid-range screens turn into a visibly better picture; HLG is broadcast television’s version, built so one signal serves both HDR and SDR sets. A television made in the last few years handles HDR10 and HLG at minimum.
What is an .hdr file?
Radiance HDR — a 1990s format from lighting research that stores real brightness per pixel, still used for 3D environment lighting and panoramas. It is not what a phone or TV means by HDR: photos use gain-map JPEG or AVIF, video uses HDR10 or Dolby Vision inside a normal video file. If you were handed an .hdr file, it is almost certainly a lighting environment for 3D software, not a photo.
Is an HDR photo the same as HDR mode on my phone camera?
The name is doing two jobs. Camera "HDR mode" historically meant merging several exposures into one ordinary SDR photo that clips less. An HDR photo in the display sense is a file whose highlights are allowed to exceed white on screen — a normal JPEG plus an embedded gain map saying how far. Recent phones quietly do both at once, which is why photos in your gallery can flash brighter than the interface around them.
Can an SDR photo be converted to HDR?
The look, yes; the lost data, no. A model can predict which highlights should glow and write that as a gain map — that is what our converter does, on your own hardware. What no conversion can do is recover detail inside a blown-out highlight: the SDR file holds nothing beyond white, so a clipped sky stays clipped, just brighter.