NegPy turns scans of film negatives and slides into finished pictures. I wrote it because I wanted a tool made for film scans that does more than invert them. It models film and photographic paper, and adds the conveniences of a lab scanner. It is written in Python and runs on Linux, macOS and Windows.
The User Guide covers every panel and control (the ⓘ on each panel opens it in the app). PIPELINE.md explains the math.
The desktop interface and panel guides support English, Simplified Chinese (简体中文), Japanese (日本語) and Korean (한국어). Choose a language in Preferences → Interface → Language, then restart NegPy. System Default follows your system language and uses English for unsupported languages. Missing panel translations fall back to English. See CONTRIBUTING.md to update or add a translation.
- The orange mask is removed from each channel's own sensitometry: no camera profiles, no border color picking.
- The print is built in density space on an H&D curve (toe, straight section, shoulder) and graded in ISO-R points like darkroom paper.
- Auto Density and Auto Grade meter each frame to adjustable targets.
- Paper profiles from Ilford, Kodak, Foma and Fuji datasheets.
- Color negative, B&W and slide modes. Slides open as captured, with optional Auto Density and Auto Grade for faded film and HDR merging of bracketed exposures.
- The library is a list of rolls: imported folders, or virtual rolls built from any frames.
- Roll-wide defaults for film mode, crop, calibration, metering, raw decode, lens and metadata, with per-frame overrides.
- Roll Analysis gives every frame of a roll, or of a scene within it, the same baseline.
- Keep/reject triage, half-frame splitting, stitching, and search by metadata or (opt-in) content.
- Film scanners: Plustek OpticFilm 8200i SE, 8100 V2, 8300i SE and 7600i v1 over USB, Nikon Coolscan, Reflecta, Pacific Image, and anything SANE supports.
- Tethered camera scanning (macOS and Linux), including narrowband RGB captures with a Scanlight and a sub-pixel Trichrome merge (guide).
- Flat-field correction, sensor calibration for narrowband light, and lens correction read from the file.
- Camera RAWs, TIFF, DNG, JPEG XL and scanner formats such as Pakon, Coolscan NEF, Flextight FFF and Noritsu.
- Dodge and burn with polygon, oval and card-edge masks, each with its own strength, feather, contrast grade and tone limit.
- Dust, hair and scratch removal: automatic, from the IR channel or painted, keeping the film grain.
- Darkroom tools: test strips, ring-around, step wedge, zone overlay, spot densitometer and zone placement.
- Contrast mask, tilt and swing, edge burn, filed carrier and print mats.
- Lith, cyanotype and toners for B&W.
- GPU rendering (Vulkan, Metal or DX12) with a CPU fallback that gives the same result.
- ICC color management, monitor profile detection and soft proofing.
- Export to JPEG, TIFF, PNG, WebP and JPEG XL, with borders, presets, contact sheets and filename templates.
- A flat 16-bit TIFF master for other editors, or a linear export that skips the pipeline.
- Gear and capture metadata written to EXIF and XMP.
- Non-destructive: source files are never modified.
- Edits live in a local SQLite database keyed by file content, so files can move. Optional
.negpysidecars sit next to the scans. - Undo history and named work prints survive a restart.
- Keyboard shortcuts can be remapped.
Download the build for your OS from the Releases page. When a new version is out, a dot shows on the ⋯ menu, and Update to vX.Y.Z… in its Help menu installs it.
To build from source, see CONTRIBUTING.md.
The builds are not signed, so expect a warning on first run.
Make the .AppImage executable with chmod +x and run it.
Optional, for SANE and camera scanning:
sudo apt install libsane # Debian/Ubuntu
sudo pacman -S sane libgphoto2 # Arch
nix run github:marcinz606/NegPyOr add it as a flake input:
{
inputs.negpy.url = "github:marcinz606/NegPy";
outputs = { self, nixpkgs, negpy, ... }: {
# negpy.packages.<system>.default
};
}- Open the
.dmgand drag NegPy to/Applications. - Run
xattr -cr /Applications/NegPy.appin Terminal. - Launch it.
Optional, for SANE and camera scanning (Homebrew):
brew install sane-backends libgphoto2
To build the DMG, set NEGPY_MACOS_ARCH=x86_64 (Intel) or NEGPY_MACOS_ARCH=arm64 (Apple Silicon).
Run the installer past the warnings.
Plustek OpticFilm scanners need the WinUSB driver, installed with Zadig in place of the SilverFast driver. See PLUSTEK_WINDOWS.md. Camera scanning is not available on Windows.
Everything is in Documents/NegPy. On Windows, if that folder is blocked, NegPy asks for another and suggests Local AppData. NEGPY_USER_DIR overrides both.
edits.db: your edits.settings.db: app settings.cache/: thumbnails. Safe to delete.export/: default export folder.icc/: paper and printer profiles.override.toml: startup overrides (below).
If NegPy crashes on startup or renders wrong, edit override.toml (written on first run). Most [performance] values are also in Preferences (Ctrl + ,), but the file wins.
[rendering]
# Options: "auto", "vulkan" (Linux/Win), "dx12" (Win), "metal" (macOS), "cpu"
backend = "vulkan"
[display]
# Qt scene-graph backend. Options: "auto", "vulkan", "d3d12", "metal", "opengl", "software"
qt_rhi_backend = "auto"
# Window system plugin (Linux only). Options: "auto", "xcb", "wayland"
qt_platform = "auto"
[performance]
# Cap GPU texture size in pixels — useful on low-VRAM cards. "auto" = no limit.
max_texture_size = "auto"
# Force HQ preview on/off. Uncomment to override saved preference.
# force_hq_preview = false
# Long edge of the interactive preview in pixels (512-8192). Higher is a sharper
# canvas and more VRAM per frame.
# preview_render_size = 1600
# Preview cache size — keeps recently-viewed photos in memory for instant navigation.
# Lower these on low-RAM machines. Uncomment to override defaults (~1.2 GB / 8 photos).
# preview_cache_max_bytes = 1200000000
# preview_cache_max_entries = 8
[logging]
# "debug", "info", "warning", "error"
level = "info"backend = "cpu" turns GPU rendering off if the GPU backend crashes.
If you like NegPy, buy me a roll of film so I have more test data :)
