Overview
ISO 18912:2002 - "Imaging materials - Processed vesicular photographic film - Specifications for stability" defines stability requirements for polyester-base processed vesicular photographic film whose image is formed by heat-created nitrogen bubbles. The standard applies specifically to vesicular film intended and used as storage copies (LE-10 and LE-100) and covers roll and sheet formats where the image layer is a discrete layer on a transparent support. It is not applicable to vesicular film used as work or reference copies. ISO 18912 emphasizes inherent film keeping behaviour and ties life-expectancy (LE) ratings to defined storage conditions (for example, LE‑100 = 100 years at 21 °C and 50% RH).
Key topics and technical requirements
- Scope and classifications
- Applies to polyester-base safety film with vesicular (nitrogen-bubble) images.
- Life-expectancy ratings: LE-10 and LE-100.
- Film classes A and B (Class A suitable for viewing and UV printing; Class B for visual use only).
- Physical and mechanical tests
- Tensile properties and allowable loss in tensile strength.
- Layer adhesion (tape-stripping, humidity-cycling adhesion tests).
- Blocking and thermal sticking behaviour under heat/pressure.
- Binder stability and resistance to high humidity.
- Image stability tests
- Proper development verification and residual diazonium-salt testing.
- Light-fading evaluation and dark-ageing tests for both minimum-density areas and vesicular image areas.
- Densitometry methods for objective measurement.
- Test methods and reporting
- Accelerated-ageing protocols, densitometry standards, and classification for reporting results.
- Informative annexes
- Effects of heat/pressure (Annex D), high humidity (Annex E), microfilm image quality, and corrosiveness.
Practical applications
ISO 18912:2002 is used to ensure the long-term stability and archival suitability of vesicular photographic storage copies. Typical applications:
- Preservation and duplication of records in national/state archives, libraries, museums.
- Long-term storage of legal, medical, historical, and industrial records on microfilm.
- Quality assessment by microfilm manufacturers and film processors.
- Specification of retention standards for banks, insurance companies, and enterprises managing long-lived records.
Who should use this standard
- Records managers, archivists, conservators
- Microfilm manufacturers and test laboratories
- Film processors and imaging-material suppliers
- Standards and compliance officers in institutions preserving long-term records
Related standards
Keywords: ISO 18912:2002, vesicular photographic film, processed vesicular film stability, LE‑10, LE‑100, archival film, film preservation, image stability, tensile properties, blocking test.