I tried to send you this message directly but the address failed.
At Ipswich Museum we used a black tape called:
Black Crepe photographic tape 25 mm wide, we bought it at
BDK
26 Anson Road
Martlesham Heath, IP16 0JE
Tel: o1473 659 059.
In the past for restoration jobs I made my own with black cotton
tape sized with rabbit skin and shellac (laborious!)
I hope this is of some help if you have found a better product, let us
know.
Dominique Rogers
Conservator, (Free lance)
Ipswich Museum.