[Maris]

You know, this is very informative.

But I wonder, dkgeorgie or anyone: Is there simply a thin, opaque tape that can be carefully wrapped into the bellows that will not tear when repeadedly bent (as will be the case as the bellows is brought in and out)? Doing this would truly build back the bellows' stability that had been lost with the wear. - David Lyga

The best bellows repair material is, I reckon, 3M type 850 black polyester tape. I use the 1" wide version to repair and almost reconstruct bellows in enlargers and cameras. The tape is very thin, very black, with a strong non-bleeding, non-gooey adhesive. It is also ultraflexible and doesn't form cracks or pinholes. Maybe bellows should be made out of this stuff in the first place. Downside? Expensive!