A possible negative consequence of recording tape being paper backed is
intimacy of the medium-to-head contact. Its typical surface (in 2010)  isn't
as smooth as acetate & plastic (at least when those substances are not
aged).   Is it known if the paper used by Brush, 3M & others were acid free?

Years ago I transferred some I.G. Farben paper tape that had been recorded
in 1944.  It broke frequently while running @ typical 'modern' tensions.  It
was self-evidently more brittle than Brush & 3M paper samples with which
I've worked.

Art (Shiffy) Shifrin
www.shifrin.net
NYC USA