ISO 18912:2002

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

• ISO 18902 (storage enclosures & containers)
• ISO 18911 (storage practices)
• ISO 18906, ISO 18905 (other film specifications)
• ISO 5-2 / ISO 5-3 (densitometry), ISO 527-3 (tensile testing)

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.