ISO 18916:2007

Overview

ISO 18916:2007 defines the Photographic Activity Test (PAT) procedure for evaluating chemical interactions between processed imaging materials and enclosure materials. The standard applies to general photographic enclosures - paper, tissue, cardboard, mat board, plastics - and enclosure components such as adhesives, inks, paints, labels, and tape. It provides a predictive ageing test to detect tendencies for image interaction, stain, and mottle that could occur during long‑term storage of photographic and digitally printed images.

Key Topics and Requirements

• Scope of applicability: Tests interactions with processed silver‑gelatin, colour (dye‑gelatin), dye‑ and pigment‑based inkjet prints, thermal dye‑diffusion (dye‑sub) prints, toner and xerographic prints, and diazo images (with a specific diazo PAT).
• Three evaluation criteria: image interaction, stain, and mottle determined using dedicated detectors and comparison with a filter‑paper control.
• Detectors and materials:
  • Image interaction detector: unprocessed colloidal (Carey Lea) silver in gelatin on polyester base.
  • Stain detector: premium non‑resin coated B/W paper processed to minimum density.
  • Specified fix and hypo‑clearing solutions are provided for detector processing.
• Accelerated ageing: Sandwiches of detector + enclosure material are incubated at 70 °C ± 1 °C and 86 % RH ± 3 % RH for 15 days to simulate long‑term storage interactions.
• Measurement: Status A blue diffuse density readings are taken before and after incubation (four locations per strip). Densitometer spectral and geometric conformance to ISO 5‑2, ISO 5‑3, ISO 5‑4 is required.
• Test construction: Test sandwiches include detectors, filter paper separators and glass; 500 Pa pressure is applied during incubation.
• Limitations: PAT assesses chemical interactions only. It does not address physical failures (blocking, dye bleed, adhesive migration, plasticizer exudation), nor does passing PAT imply a material is “archival.”

Applications and Who Uses It

• Preservation professionals, archivists, museum conservators and collections managers use ISO 18916 to evaluate enclosure safety for photographic collections.
• Manufacturers and quality‑control labs for enclosure materials and archival products (sleeves, boxes, interleaving tissues, adhesives, inks, tapes) use PAT to certify or screen products.
• Suppliers of coloured papers and inks must test each colour/lot, since composition and purity can vary; materials are typically re‑tested annually or on formulation/supplier change.

Related Standards

• ISO 18902 - Storage enclosures for photographic materials (photo‑safe requirements; includes PAT criteria)
• ISO 18901, ISO 18911, ISO 18918, ISO 18920 - Standards covering photographic material requirements and storage/processing
• ISO 5‑2 / 5‑3 / 5‑4 - Density measurement conformance used by ISO 18916

Keywords: ISO 18916:2007, Photographic Activity Test, PAT, enclosure materials, imaging materials, archival preservation, colloidal silver detector, stain test, mottle test, dye coupler reactivity, accelerated ageing.