Overly strong storage enclosures may also be problematic, adding unnecessary weight and bulk, which can lead to handling and spatial difficulties. The term permanent or permanent durable is sometimes used to describe materials that are chemically stable and durable. This standard establishes criteria for paper that will last for several hundred years under normal use and storage conditions. It is intended to be used as a guide in the selection of papers for use in publications. It can also be used as a guide in selecting papers for use as storage materials.
Different standards exist for storage enclosures for photographic materials.
Another standard that further specifies criteria for enclosures for photographs is the American National Standard for Imaging Media Photographic Activity Test , ANSI IT9.16-1993. Storage enclosures for photographs should meet both standards. 7 Plastics Plastics vary greatly in chemical stability and should be used with caution. Some plastics are unstable chemically and produce by-products as they deteriorate that accelerate the breakdown of paper. Others contain volatile plasticizers that can cause items in contact with them to stick to their surface and media to bleed.