HDR to RAW Converter
Convert HDR to RAW in your browser. You download a Linear DNG (.dng), not a .raw: only a camera can create a genuine RAW, and every editor that opens RAW also opens DNG. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
HDR expected · other image formats also work
How to use HDR to RAW
- 1
Add your HDR files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the DNG is written uncompressed. Resizing and rotating are under More options if you need them.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .dng files one at a time or together as a ZIP.
Why use Aback Images for hdr to raw
Where a RAW would go
RAW files are opened by Lightroom, Photoshop Camera Raw, Capture One, darktable, RawTherapee and dcraw-based tools, and every one of them opens the DNG too.
DNG next to HDR
The DNG is written uncompressed, so expect it to be several times larger than the HDR, which stores run-length encoded RGBE scanlines.
Written without a lossy pass
The DNG is written uncompressed, so the pixels decoded from the HDR arrive unchanged, apart from precision beyond 8 bits per channel.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
HDR vs RAW
What changes from HDR to RAW
Encoding: the HDR uses run-length encoded RGBE scanlines; RAW uses uncompressed, lossless JPEG or vendor-specific coding of the sensor data, depending on the maker, and the download is a Linear DNG: demosaiced 8-bit RGB with the colour matrices raw editors need.
Bit depth: an 8-bit mantissa per channel sharing an 8-bit exponent (RGBE), 32 bits per pixel in the HDR; RAW allows 12 to 16 bits per channel, and the DNG written here has 8 bits per channel, linearised. The high dynamic range is mapped to 8 bits per channel, and values above white clip.
Colour: linear RGB (or XYZ in the XYZE variant) in the HDR; RAW supports camera-native RGB from a colour filter mosaic, written here as 8-bit sRGB.
Metadata: the HDR can carry a text header with FORMAT, EXPOSURE and optional comments; RAW can carry EXIF and vendor maker notes, almost always with an embedded JPEG preview, but nothing is copied across.
About HDR
Radiance .hdr stores high dynamic range light values, widely used for 3D environment maps and HDRI lighting.
A Radiance file starts with '#?RADIANCE' (or '#?RGBE'), text lines such as FORMAT=32-bit_rle_rgbe and EXPOSURE, a blank line, a resolution line like '-Y 2048 +X 4096', then the scanlines.
HDR files usually come from HDRI environment maps, 360° panoramas and lighting simulation.
About RAW
Camera RAW files (CR2, CR3, NEF, ARW, DNG, ORF, RW2, RAF and others) hold the unprocessed sensor data from a camera along with an embedded full-size JPEG preview rendered by the camera.
.RAW is an extension rather than one format. Panasonic and Leica compacts wrote TIFF-like .RAW files before Panasonic moved to RW2, and scanners and scientific cameras use .raw for headerless dumps with no width, height or layout recorded, which nothing can read without being told those values.
RAW files come from older Panasonic and Leica compacts that saved .RAW, and scanners or scientific cameras that use the extension for pixel dumps.
When converting HDR to RAW makes sense
Forms and workflows that ask for RAW usually feed a raw editor, and each of those opens DNG as well, so the DNG can take the RAW's place. Keep the HDR if you only need to view or share the picture.
What RAW offers when it comes straight from the camera: Maximum editing latitude in RAW editors; Includes a camera-rendered preview. Its drawbacks: Huge files; Every brand uses its own format; Phones, browsers and websites cannot display it.
Limitations
- Light values above 1.0 are clipped rather than tone-mapped, so the sun and bright sky turn flat white.
- Environment maps are 2:1 equirectangular panoramas, so the picture looks stretched near the top and bottom, as it should.
- Files in the XYZE variant cannot be read here; RGBE files, the common kind, can.
- The DNG holds the decoded 8-bit pixels, so it adds no dynamic range or detail beyond the HDR.
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Frequently asked questions
Why do I get a .dng file instead of a .raw?
A real RAW is written by a camera and holds the sensor's own readings (12 to 16 bits per channel, stored as uncompressed, lossless JPEG or vendor-specific coding of the sensor data, depending on the maker) along with EXIF and vendor maker notes, almost always with an embedded JPEG preview. An HDR holds no sensor data, so no software outside the camera can create a genuine RAW. The Linear DNG you get instead is Adobe's open raw format, and every editor that opens RAW files opens it with the same raw controls. It holds decoded pixels, so it adds no quality or dynamic range.
Does converting HDR to RAW lose quality?
DNG is written uncompressed, so the pixels are stored exactly as decoded. The high dynamic range is mapped to 8 bits per channel, and values above white clip.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.