DT Batch — Opéra Paris

Bulk RAW → JPG converter for photogrammetry shoots. A small Tkinter GUI that drives darktable-cli over a folder tree, applies a darktable style, and mirrors the folder structure into a JPG output root.

Built for the Opéra Paris — Maquettes & Décors pipeline (MAQ###/N###/RAW/*.NEF → .../JPG/*.jpg), but the source/destination/style/ extension are all configurable, so it works for any darktable style preset.

Features

• Pick darktable-cli, source RAW root, and destination JPG root from the GUI.
• Apply any darktable style preset (--style-overwrite).
• Configurable RAW extension (NEF, CR2, ARW, RAF, …) and JPEG quality.
• Mirror mode — rebuilds the source tree under the destination, swapping the RAW folder for JPG (src/MAQ/N001/RAW/*.NEF → dst/MAQ/N001/JPG/*.jpg).
• Resume tracking — finished files are recorded in dt_progress.txt; re-running skips work already done.
• Test 1 file button to validate the style/paths on a single image first.
• Scan source to count RAW files per top-level folder before committing.
• Live progress bar, colour-coded log, and a Stop button (halts after the current file).

Requirements

• Windows
• darktable installed (uses darktable-cli.exe, default path C:\Program Files\darktable\bin\darktable-cli.exe).
• The style preset you want must already exist in darktable.
• Python 3.9+ (Tkinter ships with the standard Windows installer).

Run

python dt_batch_GUI.py

or with uv:

uv run dt_batch_GUI.py

run.bat is a convenience launcher.

Usage

1. Confirm the darktable-cli path.
2. Set Source (RAW root) and Destination (JPG root).
3. Set the style, RAW extension, and JPEG quality.
4. Click Test 1 file — you want exit code: 0 and ✓ JPG created.
5. Click Run. Stop any time; resume by running again.

Notes / darktable-cli gotchas

These are the things that quietly break batch conversion on Windows. The script already handles all of them — documented here so future-you doesn't re-debug:

• database is locked — darktable-cli shares one SQLite library and will fail to commit exports if the darktable GUI is open or a stale lock exists. Fixed by running each file with --core --library :memory: (isolated in-memory catalog). The default config dir is kept so styles in data.db still load.
• Output path must use forward slashes — darktable's disk-export module (glib) eats single backslashes, producing a garbage filename and [imageio_storage_disk] could not export to file. The script converts the output path to /. (The old workaround was doubling backslashes \\.)
• Pass an explicit output filename, not a directory — a trailing-slash directory makes darktable build a malformed ...\/$(FILE_NAME).jpg pattern that silently writes nothing while still returning exit code 0.
• Don't trust the exit code alone — darktable can return 0 and write nothing. Success is keyed off a JPG actually appearing in the temp dir.

If a "Windows cannot find …\Temp\tmp…" Explorer popup appears, it's harmless: it just means you have a File Explorer window open on the temp folder that the script created and then deleted. Close that window.

Files

File	Purpose
dt_batch_GUI.py	The GUI application.
dt_progress.txt	Resume log of completed files (safe to delete / use Clear progress.txt).
run.bat	Launcher.
assets/	Screenshot(s) used in this README.