Plustek OpticFilm 7500i Linux scanning pipeline

A Linux scanning and processing workflow for the Plustek OpticFilm 7500i using SANE's genesys backend.

It produces 16-bit RGB TIFFs at 3600 or 7200 dpi, optionally scans infrared for dust and scratch removal, and prepares the result for Lightroom / Negative Lab Pro. Original scans are preserved unchanged.

Requirements

Tested with:

• Ubuntu 22.04
• Plustek OpticFilm 7500i
• SANE / sane-backends 1.4.0 (genesys backend)
• Python 3
• libtiff-tools

Ubuntu 22.04's packaged SANE version is too old for this setup. SANE 1.4.0 is expected at /usr/local/bin/scanimage.

Verify it with:

/usr/local/bin/scanimage --version

Install the remaining system dependencies and create the Python environment:

sudo apt install python3-venv libtiff-tools
./scripts/setup.sh

The setup script installs compatible NumPy and OpenCV versions in .venv and verifies the required image codecs.

Usage

Insert film with the shiny/base side up and the emulsion side down, then start the interactive workflow:

./scan-loop.sh

Available actions:

• Enter / N — scan and process the next frame
• P — create a quick 900 dpi RGB preview
• S — select 3600 or 7200 dpi and enable or disable infrared
• Q — quit

Disable infrared for black-and-white film. The next frame number is determined from existing scans in RAW/.

Manual operation

Scan and process frame 1:

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

Create a preview:

./scripts/preview-scan.sh

Processing

With infrared enabled, processing consists of:

1. Scan 16-bit RGB and infrared TIFFs.
2. Detect defects from the infrared image.
3. Estimate RGB/infrared alignment.
4. Inpaint defects in each 16-bit RGB channel.
5. Apply gamma 2.2.
6. Mirror the image horizontally.

Without infrared, only gamma and mirroring are applied.

Scanner output is written to RAW/, temporary processing files to TMP/, and finished TIFFs to DONE/. Temporary files are removed after successful processing by default.

The scanner's output is horizontally mirrored, so mirroring is applied only to the finished image. Files in RAW/ remain untouched.

Configuration

Scanner geometry and defaults are configured near the top of scripts/raw-scan.sh. Processing parameters are configured near the top of scripts/process-scan.sh, including:

MASK_CHANNEL="0"
MASK_THRESHOLD="44000"
MASK_DILATE="0"

AUTO_OFFSET="yes"
OFFSET_MAX_SHIFT="100"

INPAINT_RADIUS="2"
INPAINT_DILATE="1"
INPAINT_METHOD="telea"

GAMMA_VALUE="2.2"

These values were tuned for one scanner and may need adjustment. A higher mask threshold selects more pixels as defects; excessive mask dilation or inpainting radius can smear texture.

Set KEEP_TMP="yes" in scripts/process-scan.sh to retain masks and intermediate TIFFs for debugging.

Scanner reset

If scanimage hangs:

pkill -9 scanimage
sudo usbreset 07b3:0c13

The scripts discover the current genesys:libusb:* device automatically after a reconnect or reset.

Limitations

• RGB and infrared are separate passes and may not align perfectly.
• Infrared can contain faint image detail, so a global threshold may select real content.
• Dust removal and alignment parameters may require scanner-specific tuning.
• This is not literal sensor RAW; SANE still performs calibration and device-level processing.

TODO:

• Multiscan (scan n-times + averaging)
• Smarter scratch detection
• all settings in ini file for other scanners