HDR & EXR to JPG

HDR images store light as it really is in a scene: the sun might be fifty thousand times brighter than a shadow under a tree, and the file records both. Radiance .hdr files and OpenEXR .exr files hold that range for HDRI environment maps, 3D renders and merged exposure brackets. Ordinary screens and formats can only show a small slice of it, so the light has to be squeezed into a normal image, a process called tone mapping. This tool does that for any .hdr or .exr file and saves a JPG, PNG or WebP.

What the readout tells you

After opening a file, three numbers appear. Dynamic range in stops says how many doublings of brightness separate the dark and bright parts of the image; ordinary photos manage about 8 to 10 stops, outdoor HDRIs often exceed 15. The brightest value shows the peak, where 1.0 corresponds to white on a normal screen. Exposure used shows how much the image was brightened or darkened to look right.

Automatic exposure

The tool measures the average brightness of the scene on a logarithmic scale, the way the eye adapts, and sets exposure so that this average lands on middle gray. That gives a balanced starting point for nearly any file. The exposure slider then shifts it up to six stops either way. One stop doubles or halves the light, so +1 makes everything twice as bright.

The three tone curves

Filmic (ACES) is modeled on the curve used in film and visual effects: it adds pleasant contrast in the midtones and rolls highlights off smoothly instead of clipping them, so skies and lamps keep their shape. Reinhard compresses bright values more evenly, keeping the most highlight detail but looking softer and flatter. Clip applies no curve at all; anything above white is cut, which suits HDR files that hold only modest values or when you want a purely technical view.

Preview and full-resolution output

HDRIs are often 8K or 16K wide. To keep the controls responsive, the preview works on a reduced copy. When you download, the full-resolution image is tone mapped with the same settings, which can take a few seconds for very large files. The result uses standard 8-bit sRGB color.

Choosing a format

JPG works for sharing previews, thumbnails for HDRI libraries and quick checks. WebP gives smaller files for web galleries. PNG is lossless and best when the tone-mapped image will be edited further.

Typical uses

Making thumbnails of an HDRI collection, checking renders from Blender, Houdini or Arnold without opening a 3D program, posting a merged bracketed photo, or creating a backdrop image from an environment map.

Supported files

Radiance files with the .hdr, .pic or .rgbe extension use the classic RGBE encoding, read by a decoder written for this site. OpenEXR files are decoded with the EXR loader from three.js, which handles the compression types commonly used by renderers. Everything is processed on your device; even very large files are never uploaded.

Keep the original

The tone-mapped result is a display image, not HDR data. For lighting scenes or further grading, always keep the .hdr or .exr master.

Related tools

To view the brightness distribution of the result, open it in the Image Histogram. The Image Resizer makes small preview sizes, and RAW to JPG handles camera raw files.