David Sharpe asked about repairing rolls where a long bridge has
collapsed.  I've seen the same problem on a few rolls and in most
cases have seen that if it collapsed in one place, it will continue
down the roll and collapse in several more.

I've tried to repair several rolls by strengthening the site but have,
in my experience, found that the damage is often stronger than the
repair -- the paper has warped and wants to be in the collapsed
position.  I haven't tried ironing the rolls, yet, though I have a
candidate that I don't want to lose, with only 2-3 collapsed lines,
so this may be my next attempt.

Another problem with this type of roll is that I've noticed that this
problem occurs on particularly brittle rolls.

Eliyahu Shahar