Quote Originally Posted by Prest_400 View Post
Polyester seems to have some interesting advantages, and it's drawbacks don't seem that important on still cameras. I'm curious on how it doesn't seem to have replaced Tri-Acetate on the still film market; obviating maybe 135 with motor winder use.
What would happen if the same thickness and material between the three kinds of finish (135, 120 and sheet) were used? I guess it would be an issue for roll film cameras when it comes down to winding tolerances. But it would maybe make lower scale manufacturing easier (one master roll for everything).
If you used one support for all films, for starters, if you used thicker support for 120 and 35mm, you would get fewer exposures per roll. If you used thinner film for sheet film, it would sag and buckle.

But, there is more to this than thickness, there is also size changes (Estar has virtually none, but acetate has quite a bit). and then there is the need for a lot of antistatic materials on motion picture films to prevent marks on the film due to high speed travel through the cameras. For that you need rem-jet. The list of "crossover problems" is quite long and involved.