By Tina Gessler, Associate Conservator of Objects
What does it mean for a material to be archival?
In the field of art conservation the terms archival, inert, stable, safe, etc. refer to materials or processing methods that are expected to allow items to be stored for extended periods of time without loss of quality. These materials should not degrade over time and should not contain volatile materials that will be emitted from the material, or ‘off-gas.’ Both degradation products and off-gassing materials can do serious damage to some art materials. Metal, paper, and shells are examples of sensitive materials that can be damaged irreversibly from proximity to ‘unsafe’ materials.
A few examples of stable or ‘archival’ materials used to house objects:
- Acrylic sheet (Plexiglas)
- Polyethylene foam (Ethafoam, Volara)
- Acid-free matboard
- Corrugated polypropylene or polyethylene boards (Coroplast)
- Acid-free corrugated paperboard
- Adhesive-free polyester fiberfill
- Natural unbleached textiles (washed)
- Some synthetic textiles
- Polyolefin fabric (Tyvek)
- Acid-free tissue
- Polyester film (Mylar)
When is it important to use archival materials?
It is more important to use archival materials to build art storage housing than it is to use archival materials for short term enclosures such as crates and packing boxes. This is because it is unlikely a non-archival material will degrade or off-gas enough to cause damage to the art over the short period of time required for transport. However, if your art will be stored in an enclosure for any length of time, housing made of archival materials is recommended. Highly sensitive materials such as silver can show damage from proximity to poor quality materials in as little as a week.
Why are archival materials expensive?
Rather than being a mixture of many kinds of relatively cheap materials, archival products are a few highly purified ingredients. It is often impurities that deem a material inappropriate for use with art. The costs associated with quality raw materials and the processes used to manufacture materials free of impurities are passed along to the purchaser.