Hi,  To repair rolls, I recommend to use acid-free archival mending tape:

- Filmoplast P (width 2 cm), or
- Lineco mending tissue (width 1/2").

These tapes are made of thin paper, and the adhesive doesn't leak
outside the tape.

I use Filmoplast P (transparent), easily found in Europe, not the P90,
which is in similar boxes but white and too thick.  I don't recommend
to use Scotch Magic Tape -- it's plastic and not paper, and I fear roll
warping depending on humidity or temperature.

I repaired some rolls with tape edgewise on 30 cm length, and it works,
but take care to _not_ tighten the tape to avoid roll warping, which is
worse than damaged edges.

For some repairs, I split the Filmoplast to obtain 1 cm tape, convenient
for small tears on the edges, or when there are pedal perforations.

Jean-Pierre Jouandet