HDRMerge creates raw images with an extended dynamic range. It does so using either multiple exposure-bracketed raw files (any camera), or a single raw file which contains multiple exposure-bracketed frames (Fuji EXR and some Pentax cameras). It can import any raw format supported by LibRaw, and outputs a DNG 1.4 image with floating point data. The output raw is built from the less noisy pixels of the input, so that shadows maintain as much detail as possible. This tool also offers a GUI to remove ‘ghosts’ from the resulting image.


Latest Stable Release

Version v0.5.0 is the latest stable release recommended for everyday use.

Latest Development Builds

These are builds of the latest development code, recommended for testing and bug reporting but not for everyday use.

Bugs and Feature Requests

File bugs and feature requests in GitHub. Make sure to provide the necessary information: which version of HDRMerge you’re using, the full contents of any error messages, and a link to your sample raw files.

Getting Started

You may want to read the manual, or jump directly to the command line help with hdrmerge --help.


Do you like HDRMerge? Do you want to keep it under development? You can make a donation through Flattr or PayPal:

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HDRMerge is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

HDRMerge is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.


HDRMerge is what it is thanks to all the people that have contributed ideas, critics and samples to improve it. In particular, thanks to the team of RawTherapee. Also, HDRMerge implements or is based on the techniques described in the following works:

  1. Ward, G. (2003). Fast, robust image registration for compositing high dynamic range photographs from hand-held exposures. Journal of graphics tools, 8(2), 17-30.


These are the most significant improvements by version. For a detailed changelog, see the git commit history.










The first public version of HDRMerge.