Shrinkage and brittleness are clearly related. Brittleness, like shrinkage, is due to the loss of moisture and/or plasticiser from the film base or emulsion, resulting in brittle film or brittle emulsion or both.
Some early tinted and toned films have particularly brittle emulsion and the technical literature of the period indicates that some dyes seem to promote brittleness of the emulsion and were avoided.
Emulsion brittleness may be temporarily alleviated, for sufficiently long for a printing procedure, in the following manner:
After several days, the film should have regained some suppleness. Do not pursue the procedure too long, or the emulsion is liable to become sticky, which will make it both more easily scratched and more difficult to copy, or the repeated rewinding will create more problems. Do not attempt this treatment with nitrate film that already shows any sign of becoming sticky.
A commercial process called Rehumid [mentioned above as a stage in the Redimension process] was devised some 30 years ago in Canada and is probably still in use in some laboratories. It was almost exactly the same in procedure as the method above except that it used a proprietary mixture of solvents in place of water. Using a solvent enabled the process to continue for much longer without softening the emulsion. It fell out of use because other procedures were as effective and solved other problems at the same time. It is not known what the long-term effects of using Rehumid might be although some film treated this way must have been treated at least 30 years ago.