ISO 18905:2002

Overview

ISO 18905:2002 - "Imaging materials - Ammonia-processed diazo photographic film - Specifications for stability" defines stability and performance criteria for polyester-base safety film that carries an ammonia-processed diazo photographic image. The standard applies to roll and sheet films whose image layer is a discrete coating on a transparent support and is intended specifically for LE-10 and LE-100 storage copies (long-term storage copies), not to work or use copies. It characterizes inherent keeping behavior and sets requirements for processed film, image stability and testing methods to support archival preservation and consistent quality.

Key topics and requirements

• Scope & applicability
  • Applies only to diazo films used as storage copies (LE-10, LE-100) and stored per ISO 18902 and ISO 18911.
  • Covers polyester safety bases (e.g., PET and PEN); films may have a maximum LE rating of 500.
• Film construction
  • Image layer must be a discrete emulsion bonded to a transparent polyester support.
• Mechanical and physical properties
  • Tensile properties and allowable loss in tensile strength (tested per ISO 527-3).
  • Film base identification procedures.
  • Safety film burning/ignition requirements (reference to ISO 18906).
• Layer and surface stability
  • Adhesion tests (tape-stripping, humidity-cycling).
  • Blocking (sticking of layers) and thermal sticking tests.
  • Binder stability requirements to prevent layer deterioration.
• Image stability
  • Tests for proper development, light-fading, and dark-ageing to classify life expectancy (LE) and film class.
  • Two film classes: Class A (visual + printable to UV-sensitive materials) and Class B (visual only).
• Test methods & reporting
  • Accelerated ageing protocols, densitometry, and classification schemes for reporting stability and LE ratings.

Applications

• Establishing acceptance criteria for archival diazo microfilm and storage duplicates.
• Quality control for manufacturers of diazo film and microfilming service bureaus.
• Preservation planning by archives, libraries, government records offices, banks and insurers that use diazo storage copies.
• Procurement specifications and compliance testing for long-term record retention.

Who should use this standard

• Archival managers, records & information managers
• Film manufacturers and processors
• Conservation laboratories and preservation specialists
• Microfilm service providers and QA engineers
• Standards and compliance officers responsible for record longevity

Related standards

• ISO 18902, ISO 18911 (storage practices and enclosures)
• ISO 18906 (safety film tests)
• ISO 18901, ISO 18912 (other imaging-material stability standards)
• ISO 5-2 / ISO 5-3 (densitometry); ISO 527-3 (tensile testing)

Keywords: ISO 18905, diazo photographic film, ammonia-processed, stability specifications, LE-100, archival film, polyester-base safety film, image stability, accelerated ageing.