When considering your cold storage needs, it is important to distinguish between polyester film supports and cellulosic supports (cellulose acetate and cellulose nitrate) since B&W polyester film does not need cold storage. This can be accomplished in a non-destructive manner by performing the Polarization Test with the use of a simple tool or “polarized film viewer.”
The following video segment will provide an introduction to the use of the viewer for the Polarization Test. Additional instructions on how to use and make a viewer for your personal use are included in downloadable PDF documents below.
The polarization test is a simple non-destructive method to identify the types of film in your collection. This test involves the use of a simple tool which relies on the properties of light as it travels through two pieces of polarized film. (16SEC)
This tool can be used to help you identify a piece of film as polyester or cellulosic, but it cannot be used to differentiate between the cellulose acetate and cellulose nitrate films. This identification is important because all cellulosic film requires cold storage and most polyester are stable in a normal archival environment. (23SEC)
Here is a brief demonstration on the use of this tool. (4 SEC)Continue to Preliminary Preparation