Greetings.  I often have to repair rolls prior to scanning.  Although
there are many methods, a couple which I have discovered are the
following:

For repairing broken bridges without causing false repeats, narrow
charting tape can be used.  I am not sure if it is made of plastic of
some sort or a heavily reinforced paper but, the type that is intended
for straight of slightly curved chart lines (not the flexible crepe
type) works very well for reinforcing bridges.

What limits the durability of the repair is the condition of the paper
itself and the care with which the tape is applied.  If you touch the
adhesive surface or soil it in any way, it will not stick.  It also
needs to be burnished to adhere well.  It is so narrow that it should
not be difficult to remove in the future, if necessary.

It is not easy to find this stuff anymore as most charting is done with
the computer but it is still made and can be purchased or ordered from
drafting and graphics are supply houses.

For those who are concerned with appearance, archival tape can be cut
into precise narrow strips with a handy little tool that was made for
rag rug making.  Mine is a "Bliss Effortless Strip Slitter" which I got
at the Salvation Army for $20.  It is a very well made little device
and comes with precision machined cutting wheels for different strip
widths.  Mine came with four different wheels but only one or two were
included originally and others were purchased as options.  I have seen
a couple of these on eBay.

The device is well enough made that you can "kiss cut" to the backing
sheet with Filmoplast archival tape but not with tissue.  With tissue,
you would have to cut all the way through.  My slitter has a one cutter
that is narrow enough to make strips for edge repair.

I have been experimenting with die cutting and have gotten pretty good
at it.  I have considered making 9-to-the-inch webbed perforated tape
(archival quality) for roll repair but it would require making custom
dies and an indexing mechanism to allow for rapid production.  I would
even consider making a dedicated machine to produce it if there was
enough demand.  It is not worth spending the time to do it for just my
own limited use.

If there is enough interest, I will add this to my list of ongoing
projects.  This is not going to be a cheap item as the tape itself is
quite expensive.  A roll of Filmoplast tape is something like $20 or
$30 and it needs to be perforated accurately without damaging the
adhesive, so it is not a trivial task.

Best regards,
Spencer Chase
Garberville, Calif.
http://www.spencerserolls.com/