Why are there different film supports?

[laser]

Entire books have been written on the characteristics of various film supports. I review the pros and cons of CTA (aka acetate) and Estar (aka Mylar or polyester) in "Making Kodak Film".

Briefly:

Estar has superior dimensional stability and physical strength. It has a memory so it can severely curl in roll film applications and also it light pipes causing fogging. Estar does not out-gas so it can be used in the vacuum of outer space.


CTA has little memory so works well in roll film applications.

 

[AgX]

It is a bit more complicated than that.
These are the main features that had been considered in the past when designing new base materials:

-) strenght
-) optical features
-) coatability
-) flamability
-) area/dimension stability
-) producibility/costs
-) archival stability


That plasticity issue might be subsumized under strenght, though should get aposition of ist own, but interestingly I have not found it discussed in literature, though on other occasions.

 

[Hexavalent]

I've just seen the "Kodak ceases CTA production" announcement morph into fear-mongering things like "ceases movie films production", "ESTAR producation stopped","ceases all film production" etc., etc., (thanks facebook- NOT)

Bob, could you clarify the situation?

As I understand it, EK is just not casting their own CTA base, but will outsource it. ESTAR is still in production. Please correct me if I'm wrong.