What's the difference between HDR and EXR?

Both store high-dynamic-range data. EXR is newer, compresses better and supports multiple channels; Radiance HDR is simpler and still widely used for environment maps.

Why won't it display in the browser?

HDR data exceeds what a standard screen can show and needs tone mapping first. No browser does that, so the file downloads instead.

My HDRI is too large to upload — what now?

Use a 2K version rather than 4K or 8K, which is usually plenty for lighting, or convert to EXR with DWAA compression.

Host an HDR file and share it as a link

Put a high-dynamic-range image online at its own address — the environment maps that light 3D scenes.

You can host:

Drop your HDR file here

Any other file works too — up to 25.0 MB, or 100.0 MB for a whole site

Free to use. Your HDR file is live at your-name.99helpers.site in about ten seconds.

What is a .hdr file?

Radiance HDR stores light values far beyond what a screen can show, which is exactly what makes it useful: an HDRI environment map wrapped around a 3D scene provides physically plausible lighting and reflections from a real location, rather than lights an artist placed by hand.

What people use HDR files for

Environment maps for lighting 3D renders
Reflection probes in game engines
Product visualisation lighting setups
Panoramic captures for VFX plates

What opens a HDR file

Blender, Maya, 3ds Max and Cinema 4D
Unreal and Unity, for reflection probes
Photoshop and Affinity Photo, with tone mapping
No browser displays HDR

How to host a HDR file

1
Drop your HDR file in
Drag it onto the box at the top of this page, or click to choose it. Files up to 25 MB are supported, and nothing is uploaded until you publish.
2
Pick an address
Type a name and we'll tell you straight away whether it's free. That becomes the link: environment-map.99helpers.site
3
Publish and share
Create a free account — that step exists so the file is yours to update, replace or delete — and the link is live within seconds.

The same three steps work for any file — see how file hosting works on 99helpers.com.

What happens when someone opens the link

The file downloads. Browsers can't display HDR data without tone mapping, so there's nothing meaningful to render.

Why host a HDR file instead of emailing it?

HDRI maps are traded between 3D artists constantly, and the files are large. A permanent link is easier than a shared drive when handing a lighting setup to a collaborator.

Worth knowing before you publish

HDR files are large — a 4K panorama easily exceeds the 25 MB limit, so a 2K version may be needed.
EXR is the more modern equivalent, with better compression and multi-channel support.
Host a tone-mapped JPEG preview so people can see the environment before downloading.

HDR hosting questions

What's the difference between HDR and EXR?: Both store high-dynamic-range data. EXR is newer, compresses better and supports multiple channels; Radiance HDR is simpler and still widely used for environment maps.
Why won't it display in the browser?: HDR data exceeds what a standard screen can show and needs tone mapping first. No browser does that, so the file downloads instead.
My HDRI is too large to upload — what now?: Use a 2K version rather than 4K or 8K, which is usually plenty for lighting, or convert to EXR with DWAA compression.

Put your HDR file online now

It takes about ten seconds, and you only make an account once the file is ready to go live.

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Hosting guides for related formats

Host an OpenEXR image Host a TIFF image Host a DDS texture file Host a PNG image Host a JPG photo

HDR is one of over 211 formats you can host — see free file hosting for any file type for the full list, or read the hosting guides for other file types.