Ooh, these are good ones!  I'll see if I can round up some filters and test

Thanks, folks.  The boxes don't contain any brand info, although I think some of
the reels are stamped Scotch.  I did actually do the pull test, and broke off
small pieces on two of the darker tapes.  Please don't tell Karl Miller, as
these tapes were under his protection until recently.  But I'm glad to know
that there are other, non-destructive ways of telling acetate tapes.  I don't
suppose there's a way to tell a PVC tape from polyester without burning it?

Rick Taylor

Quoting "Watsky, Lance" <[log in to unmask]>:

> Here are two additional methods to determine if the audio tape is acetate or
> polyester:
> 1. Polarization Test: Place the tape between two sheets of polarizing filter.
> Polyester tape will show color fringes (similar to oil on water) when viewed
> through the filters, acetate tape will not form these color bands.
> 2. Utilize Acid-Detection (A-D) Test Strips: The strips change color to
> indicate the amount of acetic acid present. Polyester tape will not make the
> strips change color. These strips are usually utilized with motion picture
> film, but can work with audio tape. They are also a better way then smell to
> determine the level of Vinegar Syndrome.
> Lance Watsky
> Preservation & Media Specialist
> The Georgia Archives
> 5800 Jonesboro Road
> Morrow, GA 30260
> 678-364-3764 (phone)
> 678-364-3860 (fax)
> [log in to unmask]
> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:[log in to unmask]]On Behalf Of Richard L. Hess
> Sent: Monday, May 03, 2004 3:41 PM
> To: [log in to unmask]
> Subject: Re: [ARSCLIST] acetate tape
> Hi, Rick,
> You could pull at the last 1" of the tape and see if it stretches or
> breaks. If it stretches, it's probably not acetate.
> 3M 201 was a late acetate tape that might be darker. I don't know about the
> Ampex line.
> Cheers,
> Richard