Overview
ISO 18920:2011 - Imaging materials - Reflection prints - Storage practices provides guidance for the dark storage, handling and inspection of photographic and digital reflection prints. It covers prints on opaque supports (fibre-base, RC/resin-coated, plastic supports such as polyester, and fabrics) and a wide range of print processes (black‑and‑white silver gelatin, chromogenic and other colour processes, dye transfer, instant prints, thermal and ink‑jet systems). The standard defines two levels of storage performance - medium‑term (suitable for a minimum of 10 years) and extended‑term (for long‑term preservation) - and addresses practical measures to maximize print longevity.
Key Topics and Requirements
- Scope and materials: Applicable to numerous print supports and processes, including processed silver prints, chromogenic, dye transfer, thermal dye transfer and ink‑jet prints.
- Storage enclosures and containers: Enclosures must meet ISO 18902 and ISO 18916 requirements. Recommended materials include uncoated polyester (PET), polystyrene, high‑density polyethylene and polypropylene. Avoid harmful materials such as cellulose nitrate and PVC.
- Orientation and stacking: Smaller prints (under 28 cm × 36 cm) may be stored vertically between rigid supports; larger prints should be stored horizontally unless mounted. Stacks should be limited in height to prevent pressure damage (standard specifies limits).
- Environmental conditions: Specifies temperature, relative humidity ranges and environmental conditioning requirements (see Clause 7) plus guidance on air purity, light exposure, and display/use limits.
- Fire‑protective storage: Guidance on fire‑resistant vaults and insulated record containers to protect prints from fire, water and firefighting agents.
- Handling and inspection: Identification, safe handling practices, and inspection intervals to detect deterioration early.
- Informative annexes: Supplemental guidance on humidity, temperature relationships, air contaminants, cold storage practices, image degradation mechanisms and print stability.
Practical Applications and Who Uses It
ISO 18920:2011 is essential for professionals responsible for preserving print collections and photographic archives:
- Archivists, conservators and records managers
- Museums, galleries and libraries
- Government and cultural heritage institutions
- Commercial photo labs and imaging service providers
- Photographers, studios and private collectors implementing preservation programs
Use cases include specifying storage room design, selecting appropriate enclosures and shelving, creating handling and inspection protocols, and choosing between medium‑term and extended‑term storage strategies.
Related Standards
- ISO 18902 - Albums, framing and storage materials for processed imaging materials
- ISO 18916 - Photographic activity test for enclosure materials
- Companion standards: ISO 18911 (film storage) and ISO 18918 (processed photographic plates)
Keywords: ISO 18920:2011, imaging materials, reflection prints, storage practices, print preservation, temperature and humidity, storage enclosures, fire‑protective storage.
