Hi, I've seen some tape, I think it's 3M (Scotch) from late in the time of acetate-base, that's pretty dark, reddish brown. Richard At 09:19 AM 5/3/2004 -0500, you wrote: >Hello folks, > >Currently I'm surveying the condition of a collection of reel tapes that are >almost entirely backed with cellulose acetate. Usually it's obvious, because >the acetate tapes practically glow when held up to the light. But >occasionally >I'm finding a tape that is just barely translucent - if I move my finger >behind >the tape pack, I can see a shadow, but I have to look hard. > >Is there another formulation for acetate tape that isn't nearly as >translucent? >Because the others are so obvious, I would have marked this kind down as >polyester or PVC, except that one of them seemed to have a slight vinegar >odor. > >Thanks, > >Rick Taylor >Graduate Student >Preservation and Conservation Studies >School of Information >University of Texas at Austin >[log in to unmask]