Quote Originally Posted by DanielOB View Post
...As I can understand Acetate base is what we get with B&W films, 35mm to 4x5"...
35mm and 120/220, not 4x5". While there may be an arcane exception or two, black and white sheet film today is coated on polyester base. There are also a few roll films on polyester, but not from the "big three" manufacturers.

Until recently a few color sheet films were still on acetate, but most I'm aware of have been transitioned to polyester too.