Overview
ISO/TR 18160:2014 - Document management - Digital preservation - Analog recording to silver‑gelatin microform - provides guidance and test methods for evaluating the consistency and quality of digital images recorded onto black-and-white silver‑gelatin microfilm. The Technical Report covers quality control across the end‑to‑end workflow: capture from document scanners (digitally born or scanned), image preparation, and recording to microfilm (16 mm, 35 mm, 105 mm roll microfilm or microfiche) using film image recorders. Test methods are primarily based on visual examination and the use of both commercial and ISO‑approved test targets.
Key topics
- Scope and applicability: Assessment of office document scanners and film image recorders when producing microform for long‑term preservation.
- Test targets and methods: Use of ISO and commercial digital targets (including references to ISO test charts) to measure system consistency and resolution.
- Image creation best practices:
- Recommended scanning resolution for preservation and OCR: 300 dpi (higher DPI for very small fonts).
- Thresholding guidance for bitonal conversion: midpoint is 128 but typical practical settings around 160–180 for robust reproduction.
- Importance of calibration, brightness/contrast, and resolution settings.
- Image recording and film processing quality control: Procedures to monitor film writer and chemical processing to maintain output over time.
- Operational controls: Daily use of standardized targets, mechanical maintenance, and cleaning to avoid defects (e.g., dirt causing spots on film).
- Visual test methodology: Practical, visual inspection techniques to verify resolution (line‑pair targets) and image integrity after recording.
Applications
ISO/TR 18160 is intended for practitioners who need to convert and preserve digital documents as analog microforms or verify the quality of that conversion:
- Archivists and records managers seeking durable analog backups for long‑term preservation.
- Libraries, national archives, and government agencies that require LE‑grade microfilm retention strategies.
- Digitization service providers and microfilm vendors validating film image recorders and scanner chains.
- Quality assurance specialists in document imaging workflows responsible for scanner calibration, thresholding, and film processing control.
Practical benefits include standardized test procedures, improved consistency of microfilm output, and reduced risk of information loss due to digital obsolescence.
Related standards
Keywords: ISO/TR 18160, digital preservation, silver‑gelatin microform, microfilm, microfiche, document scanner quality control, film image recorder, archival preservation, test targets, quality control procedures.