Best Treatment for shrunken print

[David Monard Ice]

I have a print of SAFETY LAST and suddenly, it just breaks/stops. Of course in the last reel, and during the climb. I've physically touched/scanned the entire print--but then it just STOPS in my Elmo ST1200HD. No other print has ever done that.

I notice that the take up reel is sort of cupping--not winding tight. It's the print--any other film winds perfectly. And the film itself seems cupped.

I know there's a debate about Film Guard, Film Renew, Vitafilm et.al. Any advice, please? I've only had one "gag" destroyed--but I'm too terrified to run the print anymore, after about 8 splices in 2 minutes! (And weirdly, the rest of the show runs fine!)

[Ed Gordon]

Vinegar Syndrome
Vinegar Syndrome is a breakdown of the acetate base. When deterioration occurs, acetic acid vapors are produced, creating a distinctive vinegar aroma. The acid produced accelerates the process. Keeping the film in a sealed can traps the vapors, accelerating it further. Vinegar Syndrome causes the film to warp, shrink and become brittle. High humidity and high temperature speed the process. I suspect that residual processing chemicals are a significant factor. Polyester base film is immune to vinegar syndrome. The earlier diacetate film (before the mid 1940s) might be slightly less prone to vinegar syndrome, but often emits a camphor or "mothball" smell due to the plasticizers used. Agfa-Gevaert stock emits a peculiar odor, which should not be confused with vinegar syndrome.

http://paulivester.com/films/preserve.htm

What you can do
Shrinkage due to chemical decay is irreversible. Prevention of shrinkage requires storage in a cold or frozen and moderately dry environment, since such an environment will stall the progress of chemical decay.

https://www.filmcare.org/vd_shrinkage.php

Currently there is no practical way of halting or reversing the course of degradation. Many film collectors use camphor tablets but it is not known what the long term effects on the film would be.

https://en.wikipedia.org/wiki/Cellulose_acetate_film