Plustek OpticFilm 7500i scanning pipeline

Linux workflow for scanning film with a Plustek OpticFilm 7500i through SANE's genesys backend. It creates 16-bit RGB TIFFs at 3600 or 7200 dpi and can use an infrared pass for dust and scratch removal.

Pipeline

                               ┌──────────────────────────┐
Film ──► OpticFilm scanner ───►│ 1–16 linear RGB captures │──► RAW/
          │                    └────────────┬─────────────┘
          │                                 │
          │                       capture count > 1?
          │                         yes │       │ no
          │                             ▼       │
          │                    align + average  │
          │                             └───┬───┘
          │                                 ▼
          │                           merged RGB
          │                                 │
          │       IR disabled ──────────────┼─────────────────────┐
          │                                 │                     │
          │ IR enabled                      ▼                     │
          └────────► IR capture ──► estimate RGB/IR offset        │
                             │             │                      │
                             ▼             ▼                      │
                       detect defects ──► inpaint RGB             │
                                           │                      │
                                           └──────────┬───────────┘
                                                      ▼
                                              gamma 2.2 + mirror
                                                      │
                                                      ▼
                                                    DONE/

Raw captures are never modified. Intermediate files go to TMP/; completed images go to DONE/.

Requirements

Tested with Ubuntu 22.04, Python 3, libtiff-tools, and SANE 1.4.0. Ubuntu 22.04's SANE package is too old; this project expects scanimage at /usr/local/bin/scanimage.

/usr/local/bin/scanimage --version
sudo apt install python3-venv libtiff-tools
./scripts/setup.sh

setup.sh creates .venv and installs the required NumPy, OpenCV, and TIFFFile versions.

Usage

Insert film shiny/base side up and emulsion side down, then run:

./scan-loop.sh

At startup, the loop checks the scanner, command-line tools, Python packages, pipeline scripts, and writable output directories. Each available requirement is marked [OK]; the loop exits before scanning if a requirement is missing.

Controls:

• Enter / N — scan and process the next frame
• P — make a quick 900 dpi preview
• S — set resolution, RGB capture count, IR, and scratch level
• Q — quit

Disable IR for black-and-white film. Frame numbering continues from the files in RAW/.

Manual commands:

./scripts/raw-scan.sh 1
./scripts/process-scan.sh 1
./scripts/preview-scan.sh

Files and recovery

For frame NNN, the pipeline writes:

• RAW/scan-NNN-rgb.tif — first RGB capture
• RAW/scan-NNN-rgb-02.tif … -16.tif — additional captures
• RAW/scan-NNN-ir.tif — optional IR capture
• RAW/scan-NNN-capture.ini — capture settings and completion state
• DONE/scan-NNN.tif — RGB-only result
• DONE/scan-NNN-scratch-low.tif or -high.tif — IR-cleaned result

Captures and final images are published atomically and existing files are not overwritten. Re-running an interrupted raw-scan.sh with identical settings resumes at the first missing capture. Processing rejects incomplete captures and leaves failed intermediates in TMP/ for diagnosis.

The high scratch profile is more aggressive. If it repairs more than REPAIR_WARNING_PERCENT (5% by default), the pipeline warns and also creates the low variant. Successful temporary files are removed unless KEEP_TMP=yes.

Configuration

Settings live in config.ini, including paths, scanner geometry, scan defaults, multiscan alignment, scratch detection, inpainting, gamma, and cleanup. Environment variables override settings for one command:

RESOLUTION=7200 MULTISCAN_COUNT=4 IR_ENABLED=no ./scripts/raw-scan.sh 1
SCRATCH_LEVEL=low KEEP_TMP=yes ./scripts/process-scan.sh 1

Plustek OpticFilm 7500i note: Using multiscan with at least two RGB captures (MULTISCAN_COUNT=2 or higher) dramatically improves color response in testing, for reasons that are not yet understood. Prefer multiscan over a single capture when scan time and storage permit.

Scratch thresholds are scanner- and film-dependent. Start with low; aggressive thresholds, dilation, or inpainting can remove real image detail.

Scanner reset

If scanimage hangs:

pkill -9 scanimage
sudo usbreset 07b3:0c13

The scripts rediscover the genesys:libusb:* device after reconnecting it.

Limitations

• RGB and IR are separate passes and may not align perfectly.
• Multiscan registration corrects translation, not rotation or line-by-line drift.
• Every additional RGB capture requires another full 16-bit TIFF.
• IR may contain image detail, so defect masks require tuning.
• SANE still performs calibration and device-level processing; output is not sensor RAW.

TODO

• Improve scratch detection.
• Add scanner-specific configuration profiles.