Merge bracketed photos into HDR in your browser

You can merge bracketed photos into one HDR image in your browser with Light, the raw developer in Madosuite. Its Photo Merge lines up the frames, removes ghosts from things that moved, and gives you one photo with detail in both the sky and the shadows.

The files stay on your device the whole time. Here is how it works, from shooting to export.

What HDR merge does

A camera can only hold so much range in one shot. Expose for a bright window and the room goes black; expose for the room and the window turns white. Bracketing means you take the same scene several times at different exposures. An HDR merge combines them, keeping the highlights from the darker frames and the shadows from the brighter ones.

Shoot your brackets

A good merge starts at the camera:

Use a tripod if you can. Light aligns frames for you, but less movement means a cleaner result.
Turn on auto exposure bracketing (AEB), or change the shutter speed by hand between frames.
Keep the aperture and ISO the same for every frame. Change only the exposure time.
Cover the range. The darkest frame should keep detail in the brightest part of the scene, and the brightest frame should show the shadows.
Shoot raw if your camera allows it. Light opens DNG and raw files from Canon, Sony, Nikon, Fujifilm, Panasonic, Pentax and Olympus, as well as JPEG and TIFF.

Merge the photos in Madosuite

Go to madosuite.com and open the desktop.
Open the Store and add Light. It takes one click.
Open Files, press Upload, and pick all the frames of one bracket.
Open them with Light, so they appear in its library.
Select the frames of the bracket.
Use Photo Merge to merge them as HDR. Light aligns the frames automatically and can remove ghosts, such as a person walking through or leaves moving between shots.

If you shot a bracketed panorama, Light can also merge an HDR Panorama, and that result is written as a DNG. For panoramas without brackets, see stitch a panorama from raw files.

Tone the merged photo

The merged photo holds more range than a screen can show at once, so you shape it with the usual develop controls:

Highlights and Shadows first. Pull Highlights down to bring back the sky; lift Shadows to open the dark parts.
Whites and Blacks to set the ends of the range.
Tone Curve for a gentle S if the image looks flat.
Masks to work on one area: a linear gradient for the sky, or a brush for a doorway.

Light’s pipeline is non-destructive and works in 32-bit float, so you can push and pull without changing the source files. Press the backslash key to compare with the Before view.

Avoid pushing every slider to the end. A natural-looking HDR keeps some shadow and some bright highlights.

Export the result

Export as JPEG for sharing, or as TIFF or DNG to keep more data for later. Light can also export HDR files for HDR screens: gain map JPEG, PQ/HLG AVIF, PQ PNG or JPEG XL, and float TIFF.

Then open Files and download what you exported.

Limits

Light is an alpha, “young and moving fast” in its own words. Things to know:

No HDR on screen yet. Light can edit and export HDR, but it cannot show HDR brightness on your display yet. It offers a Visualize HDR view and an SDR rendition instead.
Some raws do not decode yet: some Canon CR3 variants, compressed Olympus and Samsung raws, and Nikon HE NEF. Light shows the embedded preview for those, so check that every frame opens as a real raw before you merge.
Camera colour is estimated for many cameras, not measured.
WebGPU in the browser is still in progress, so a merge of large raws can take time.

Light is one of the ArtCraft team’s open-source Crafting Apps (MIT or Apache-2.0), under a Madosuite name.

More about raw files: open raw files. Start with the app on the Light page.