nikgimp

A GIMP3 Nik-Collection Plugin

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nikgimp

A Python GIMP plugin for processing images using external Nik Collection programs.

Compatibility

Prerequisites: Make sure the Google Nik Collection is installed on your system before proceeding.
It was tested with the v1.2.11, you could still find it on the internet
or try this download link Google Nik Collection v1.2.11, which contains both Win & Mac installation.

  • GIMP version >= 3.0.0
  • Windows 10, 11 (tested)
  • Unix-like i.e. Linux with Wine & MacOS may need a little further fine-tune

Installation

  1. Create a folder named nikplugin/ under the plug-ins folder of your GIMP installation
  2. Copy nikplugin.py (latest) into the folder and ensure that the script is executable 
     GIMP_INSTALLATION_PATH/lib/gimp/3.0/plug-ins/nikplugin/nikplugin.py
  3. (Re)start GIMP, the plugin should appear under the menu Filters > NikCollection

Note: For details see Wiki - Installation
Note: see also TROUBLESHOOTING if Nik is installed in a non-default location.

Update

  • Replace the script with the latest version or stable releases nikplugin.py in this repository and restart GIMP

Uninstall

  • Remove the folder nikplugin/ from your plugin-ins directory

Usage

After installation, you can access the Nik Collection filters from GIMP’s Filters menu.
The plugin sends the current image to the selected Nik Collection program, and after processing, will return the result to GIMP.
See demo video.

License

This code revises the original shellout.py script to make it compatible with the API in GIMP v3.x. It maintains the same functionality but updates the implementation to work with the GIMP Python API v3.0.

This plugin has the same license GNU GPLv3 as the original shellout.py script it’s based on.

RELEASE NOTES

To download certain nikplugin.py version

  • Click on the version number to go to the file with this specific version
  • Click on “Download raw file” icon

v3.1.0 (2025-04-01)

Added:

  • Handle multi-layer inputs for hdr efex pro 2

Changed:

  • Refactor functions to reduce cognitive complexity

v3.0.5 (2025-04-01)

Fixed:

  • Select active layer correctly for filter program

v3.0.4 (2025-03-30)

Changed:

  • Improve code quality

Fixed:

  • Don’t display warning message when cancelling hdr filter program

v3.0.3 (2025-03-30)

Changed:

  • Enhance installation path detection
  • Make Nik program invocation work with MacOS

v3.0.2 (2025-03-30)

Fixed:

  • Handle troublesome hdr efex pro 2 internally

v3.0.1 (2025-03-25)

Changed:

  • Create program list dynamically

v3.0.0 (2025-03-25)

Added:

  • Make plugin compatible with Gimp v3.x

previous versions:

Troubleshooting

Custom installation path

Specify path in the variable NIK_BASE_PATH of the script to match your machine configuration, If you have installed Nik Collection in a non-default location.
Following paths are considered default:

  • Linux with Wine: $HOME/.wine/drive_c/Program Files
  • macOS: /Application
  • Win: C:/Program Files

Plugin doesn’t show up in the menu

Please verify with these following checks.
In most case a new reinstallation of latest GIMP3 version resolves the issues.
After all, you could find posts, ask gimp-forum.net or file an issue report with details.

1. Verify GIMP installation

Ensure GIMP3 is properly installed with Python support:

  1. Add official demo plugin GIMP_INSTALL/lib/gimp/3.0/plug-ins/test-dialog/test-dialog.py
  2. Restart GIMP and check if the test plugin appears under Filters > Development > Demos
  3. If the Test dialog... plugin isn’t there either, then is not an issue with this plugin but general GIMP problem, a reinstallation may help.

2. Check plugin location

In GIMP, go to Edit > Preferences > Folders > Plug-ins, ensure that we placed plugin folder in one of the listed directories there. This may differ between machine-wide and user installations.

3. Test Python module availability

  1. Open GIMP > Filters > Development > Python-Fu > Python Console
  2. Input these imports into the interpreter and press Enter: 
    import gi
gi.require_version("Gimp", "3.0")
gi.require_version("GimpUi", "3.0")
gi.require_version("Gegl", "0.4")
from gi.repository import GLib
from gi.repository import GObject
from gi.repository import Gegl
from gi.repository import Gimp
from gi.repository import GimpUi
from gi.repository import Gio
from gi.repository import Gtk

Any error indicates that the necessary Python module is missing and it’s a GIMP issue that reinstallation may help.

4. Check file & permissions

  • Ensure you downloaded the latest version of the plugin and the file content is intact, as Python is sensitive to indentation.
  • Under Unix-like, the script must has executable permission: chmod +x nikplugin.py

5. Check for error messages

Run GIMP console in verbose mode from command-line:

GIMP_INSTALL/bin/gimp-console-3.0.exe --verbose

If error occurs, gimp reinstallation may resolve issue or file a report.

HDR Efex Pro 2 issues

Documents Folder Not Found

warning message:

**HDR Efex Pro 2: Folder not found**
Plugin cannot identify 'Documents' on your system

Solution:

  • Modify the candidate_paths list in the find_hdr_output() function of your nikplugin.py script to include your Documents folder location if you specified it differently from the default.

  • To determine your Documents folder location, right-click on your ‘Documents’ folder and select Properties > Location (win).

  • Background information: HDR Efex Pro 2 doesn’t override the input image when you click “Save”. Instead, it saves the output at Documents/INPUT_FILENAME_HDR.ext (win). Since GIMP Python cannot use additional lib (i.e. win32com.client) to query the exact Documents path, it relies on common default locations.

Output File Not Found

warning message:

**HDR Efex Pro 2: File not found**
Plugin cannot find the output [filename] in 'Documents'
  1. The plugin found Documents folder
  2. But the expected output file wasn’t there after HDR Efex Pro 2 completed

This typically happens when:

  • HDR Efex Pro 2 saved the file to a different location
  • HDR Efex Pro 2 failed to save the file
  • The file was saved with a different naming pattern than expected

Solution: When GIMP plugin starts the filter program, go to SETTINGS > IMAGE OUTPUT SETTINGS > Image Output Format > JPG. It’s the default image format that the plugin expects.

Support

Feel free to ask questions at discussions.

Or report a bug on GitHub. Please ensure to check the reported issues and the troubleshooting first.

Buy me a coffee ☕, if you appreciate my work and found it helpful.