JP2 to HDR Converter
Convert JP2 to HDR in your browser. JP2 files usually come from libraries and digital archives, medical (DICOM) and satellite imaging, and digital cinema packages; HDR is the better fit for 3D lighting and environment maps. You get a Radiance RGBE (.hdr) file, with the 8-bit sRGB values converted to linear light. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
JP2 expected · other image formats also work
How to use JP2 to HDR
- 1
Add your JP2 files: drop them here, choose them, or paste from the clipboard.
- 2
Pick the colour that replaces transparent areas, since HDR has none.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .hdr files one at a time or together as a ZIP.
Why use Aback Images for jp2 to hdr
Where the HDR goes next
HDR opens in Blender, Photoshop, Houdini, Unreal Engine, Unity and Affinity Photo.
HDR next to JP2
Both sides are lossless, so the size depends on how well the HDR encoder handles this picture compared with the JP2's wavelet coding: reversible 5/3 for lossless files, irreversible 9/7 for lossy ones.
Written without a lossy pass
The HDR is written losslessly, so the pixels decoded from the JP2 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.
JP2 vs HDR
What changes from JP2 to HDR
Encoding: the JP2 uses wavelet coding: reversible 5/3 for lossless files, irreversible 9/7 for lossy ones; HDR uses run-length encoded RGBE scanlines, and the download is a Radiance RGBE (.hdr) file, with the 8-bit sRGB values converted to linear light.
Bit depth: up to 16 bits per channel is common, more is possible in the JP2; HDR allows an 8-bit mantissa per channel sharing an 8-bit exponent (RGBE), 32 bits per pixel, and the HDR written here has RGBE, 32 bits per pixel. 12 and 16-bit JPEG 2000 files are reduced to 8 bits per channel.
Colour: sRGB, greyscale, YCC or a space described by an ICC profile in the JP2; HDR supports linear RGB (or XYZ in the XYZE variant), written here as linear-light RGB.
Transparency: the JP2 stores it as an extra component flagged as opacity; the HDR has none, so transparent areas are filled with the colour you choose.
Metadata: the JP2 can carry XML, ICC and resolution boxes; HDR can carry a text header with FORMAT, EXPOSURE and optional comments, but nothing is copied across.
About JP2
JPEG 2000 is a wavelet-based format that can be truly lossless or lossy, handles very high bit depths and huge images, and is used where long-term fidelity matters: archives, medicine, satellites and digital cinema.
A .jp2 file is a box structure: a 12-byte signature box, an 'ftyp' box, a 'jp2h' header box with the size and colour specification, then the 'jp2c' box holding the codestream, which begins with FF 4F FF 51.
JP2 files usually come from libraries and digital archives, medical (DICOM) and satellite imaging, and digital cinema packages.
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.
When converting JP2 to HDR makes sense
HDR is the better choice for 3D lighting and environment maps, while JP2 suits archival masters and specialist imaging.
HDR strengths: True high dynamic range; Standard for HDRI environment maps. Drawbacks to weigh: Needs tone mapping to view on normal screens.
Limitations
- A JPEG 2000 file may be a lossless master or a lossy derivative; the file does not tell you which at a glance, so keep the original either way.
- Archival scans can be tens of thousands of pixels across, and decoding them needs a lot of memory on a phone.
- No range is added: the HDR holds the 8-bit picture in linear light, and nothing in it is brighter than the original white.
- 3D software treats the file as linear light, so an ordinary photo used as an environment map may need its exposure raised to light a scene well.
More conversions
Related tools
Convert HDR to JP2 in your browser, stored as lossless JPEG 2000. Batch, private, no uploads.
Convert JP2 to JPG in your browser, with transparency filled in a colour you pick. Batch, private, no uploads.
Shrink JPG, PNG, WebP, AVIF and GIF files with MozJPEG, OxiPNG and modern codecs, with a live before/after preview.
Resize to exact pixels, a percentage or a longest side, with Lanczos3 and Magic Kernel resampling. Batch ready.
Strip EXIF, GPS, XMP, IPTC and comments losslessly. Pixels are never re-encoded for JPG, PNG and WebP.
Convert between 34 image formats in bulk: HEIC, WebP, AVIF, JPEG XL, PNG, JPG, GIF, TIFF, SVG, ICO, PSD, RAW and more.
Frequently asked questions
Does converting JP2 to HDR lose quality?
HDR is written losslessly, so the pixels are stored exactly as decoded. 12 and 16-bit JPEG 2000 files are reduced to 8 bits per channel.
What happens to transparency when converting JP2 to HDR?
JP2 stores transparency as an extra component flagged as opacity. HDR has no alpha channel, so transparent pixels are composited onto a solid colour, white unless you pick another. To keep transparency, convert to PNG, WebP or AVIF instead.
Does saving as HDR make a real HDRI?
No. A real HDRI is merged from several exposures. This file holds an 8-bit image in linear light, so 3D software reads it correctly, but it has no more range than the source.
Which apps open HDR files?
Blender, Photoshop, Houdini, Unreal Engine, Unity and Affinity Photo. It does not open in web browsers.
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.