FREEDOM251

Freedom251 › HDR Software

HDR Merge Master

Free plan LinuxMacWindows

Visit HDR Merge Master Alternatives

HDR Merge Master's own site

What HDR Merge Master is

HDR Merge Master combines exposure-bracketed images in batches using Blender’s compositor, producing 32-bit OpenEXR or Radiance HDR files. It can process multiple input folders and, optionally, their subfolders; batch lists can also be imported or exported as JSON. Alignment options include no alignment, Hugin pre-alignment, or MTB alignment, depending on Blender version and mode. The tool creates tonemapped JPG previews alongside merged files. Processing camera RAW images requires RawTherapee, and adjacent PP3 profiles are used automatically. Optional workflows include Blender, Hugin, Luminance HDR, and PTGui; an included script can substitute EXR paths for JPG paths in a PTGui project. A headless command-line mode supports folder processing, JSON batches, alignment and thread settings, and cleanup. The project is actively tested with Blender 4.5 LTS and 5.1 LTS; older Blender versions use a legacy script with fewer features. It does not remove ghosting, and the maker recommends a steady tripod. HDR Merge Master is free and open source, with builds for Windows, macOS, and Linux.

Who it suits

It suits photographers creating HDRIs for stitching, especially those who want to batch exposure brackets and replace JPG previews with EXR files before final export.

What it does well

  • Free and open source.
  • Outputs OpenEXR or Radiance HDR.
  • Processes multiple folders and subfolders.
  • Offers command-line batch processing.
  • Runs on Windows, macOS, and Linux.

What to know first

  • Does not remove ghosting.
  • RAW processing requires RawTherapee.
  • Older Blender versions have reduced features.

Getting started

  1. Open the project website on GitHub.
  2. Download a build from GitHub Releases for Linux, macOS, or Windows.
  3. For the documented Windows installation route, run hdr_merge_master.exe.
  4. Use Blender 4.5 LTS or 5.1 LTS for the actively tested versions.
  5. If processing camera RAW files, use RawTherapee.

Verdict

HDR Merge Master offers batch HDR merging with multiple output formats and alignment choices. Account for its lack of ghost removal and its dependence on RawTherapee for camera RAW processing.

Questions

How much does HDR Merge Master cost?

It is free and open source under the GPL-3.0 license.

Which platforms are supported?

The project lists Linux, macOS, and Windows.

What formats can it create?

Merged HDR output can be 32-bit OpenEXR or Radiance HDR. It also creates tonemapped JPG previews.

Can it process camera RAW files?

Yes, but RAW processing requires RawTherapee. Adjacent PP3 profiles are used automatically.

Which Blender versions are actively tested?

The project actively tests Blender 4.5 LTS and 5.1 LTS. Older versions use a legacy merge script with reduced features.

Does it remove ghosting?

No. The maker advises using a steady tripod.

Facts from HDR Merge Master's own pages

Alignment
It offers no alignment, Hugin-based pre-alignment, or MTB alignment modes, with MTB as the default. · github.com, 4 Oct 2026
Automation
A headless command-line mode supports batch files, folder input, recursive processing, alignment options, thread counts, and cleanup. · github.com, 4 Oct 2026
Batching
The app supports multiple input folders, recursive processing, and batch lists that can be imported or exported as JSON. · github.com, 4 Oct 2026
Batch processing
Users can add multiple input folders and optionally process subfolders recursively. · github.com, 3 Oct 2026
Blender versions
Blender 4.5 LTS or 5.1 LTS are actively tested; older versions use a legacy script with reduced features. · github.com, 3 Oct 2026
Download
The installation instructions direct users to download the latest GitHub release and run hdr_merge_master.exe. · github.com, 4 Oct 2026
HDRI workflow
The maker says Poly Haven uses the tool to merge exposure bracket sequences for HDRI creation. · github.com, 4 Oct 2026
HDR output
The output format can be 32-bit OpenEXR or Radiance HDR. · github.com, 3 Oct 2026
Integrations
The project documents optional use of Blender, RawTherapee, Hugin, Luminance HDR, and PTGui workflows. · github.com, 3 Oct 2026
License
The repository identifies its license as GPL-3.0. · github.com, 4 Oct 2026
Linux builds
The release notes state that Linux release binaries were added. · github.com, 4 Oct 2026
Maker
The repository owner is Greg Zaal, whose GitHub profile lists South Africa. · github.com, 3 Oct 2026
Notable limit
The tool does not perform ghost removal, and the README recommends using a steady tripod. · github.com, 3 Oct 2026
Notable limitation
The tool does not remove ghosting, and the maker advises using a steady tripod when shooting. · github.com, 4 Oct 2026
Other integrations
The workflow can use Hugin's align_image_stack for image alignment and includes a script to replace JPG paths with EXR paths in PTGui project files. · github.com, 4 Oct 2026
Output formats
Merged output can be 32-bit OpenEXR or Radiance HDR, and the app also creates tonemapped JPG previews. · github.com, 4 Oct 2026
Preview files
The tool creates tonemapped JPG previews alongside the merged HDR files. · github.com, 3 Oct 2026
PTGui workflow
An included script can replace JPG paths with EXR paths in a PTGui PTS project. · github.com, 3 Oct 2026
Purpose
HDR Merge Master uses Blender's compositor to merge exposure brackets in bulk into 32-bit EXR files. · github.com, 4 Oct 2026
RAW processing
RAW input is supported when RawTherapee is installed and the RAW option is enabled. · github.com, 4 Oct 2026
Release downloads
The project distributes downloadable builds through GitHub Releases. · github.com, 3 Oct 2026
Requirements
The maker actively tests with Blender 4.5 LTS and Blender 5.1 LTS; older Blender versions use a legacy merge script with reduced features. · github.com, 4 Oct 2026
What it does
HDR Merge Master uses Blender’s compositor to merge exposure brackets in bulk into 32-bit EXR files. · github.com, 3 Oct 2026
Who it is for
The README describes the intended workflow as creating HDRIs for stitching, then swapping JPG previews for EXR files before final export. · github.com, 3 Oct 2026

Where HDR Merge Master stands on Freedom251

Look at these too