Dear list,
Due to a recent experience with an historical sound archive, I am trying to get some insight into the details of aged magnetic tape and tape preservation. I thought I had this right but now I am confused by the description the literature does relating the methods that are used to distinguish acetate from polyester tape. At first I had understood that acetate is tranlucent when held agains the light, and here are some quotes that support that:
"almost all post WWII acetate tapes, you can hold them up to the light and see light through the edges of the tape pack." <http://www.richardhess.com/notes/formats/magnetic-media/magnetic-tapes/a-base-film-primer/> " "All standard play, most long play, and some double play acetate tapes have a translucent wind when held against a light source. This is not the case with PVC or polyester tapes." quoted from a technical paper found at <www.iasa-web.org>
however when I finally got to read what seems one of the most quoted studies on the topic (IPI Storage Guide for Acetate Film) I found: