Last Updated on March 1, 2026
OpenEXR is a high dynamic-range (HDR) image file format developed by Industrial Light & Magic for use in computer imaging applications.
The format has 16-bit floating-point color component values, supports 32-bit unsigned integer and 32-bit floating-point data types, and several lossless compression methods.
It’s released under an open source license.
It provides the following tools:
- exrheader, a utility for dumping header information.
- exrstdattr, a utility for modifying OpenEXR standard attributes.
- exrmaketiled, for generating tiled and rip/mipmapped images.
- exrenvmap, for creating OpenEXR environment maps.
- exrmakepreview, for creating preview images for OpenEXR files.
- exrdisplay, a sample application for viewing OpenEXR images on a display at various exposure settings.
- IlmImf, a library that reads and writes OpenEXR images.
- Half, a C++ class for manipulating half values as if they were a built-in C++ data type.
- Imath, a math library with support for matrices, 2d- and 3d-transformations, solvers for linear/quadratic/cubic equations, and more.
Key Features
- Higher dynamic range and colour precision than existing 8- and 10-bit image file formats.
- Support for the “half” 16-bit floating-point pixel format.
- Multiple lossless image compression algorithms. Some of the included codecs can achieve 2:1 lossless compression ratios on images with film grain.
- Extensibility. New compression codecs and image types can easily be added by extending the C++ classes included in the OpenEXR software distribution. New image attributes (strings, vectors, integers, etc.) can be added to OpenEXR image headers without affecting backward compatibility with existing OpenEXR applications.
Website: www.openexr.com
Support: Documentation
Developer: Florian Kainz, Rod Bogart, Drew Hess, Paul Schneider, Bill Anderson, Wojciech Jarosz, Andrew Kunz, and many contributors
License: Modified BSD License
Related Software
| HDR Imaging Software | |
|---|---|
| RawTherapee | The Experimental Raw Photo Editor |
| OpenEXR | HDR image file format and HDR utilities |
| Hugin | Panorama photo stitching program |
| pfstools | Command line HDR manipulation programs |
| tev | High dynamic range image comparison tool |
| HyperHDR | Ambient lighting implementation for television and music sets |
| HDRView | Depth-map and high-dynamic range image viewer |
| Luminance HDR | Provides a workflow for HDR imaging |
| Radiance | Lighting simulation and rendering system |
| HDRMerge | Combine two or more raw images into a single raw |
| CinePaint | Works with 16-bit and floating point pixels for HDR imaging |
Read our verdict in the software roundup.
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