It's certainly not EXACTLY portra 400. Cinema film is physically thicker (and less prone to curling) than standard CN film and the verita matches this. Of course they could paint the portra chemical emulsion onto the thicker film base.
Thickness-wise, this is true now for 35mm color negative film.
Cinema film and regular 35mm still film from Kodak are both on 0.135mm base. I did confirm this with my calipers, both films are approximately 0.16mm thick, including emulsion.
Not anymore. The current 35mm photography color negative films from Kodak are on 0.10 mm polyester base (or at least that is what the data sheets say). Personally, I hate the polyester film base and much prefer the traditional cellulose acetate film base.
I think 35mm Ektachrome E100 is still on acetate base, and I have some hope that maybe it will stay this way, as perhaps it shares coating production with the motion picture Ektachrome 100D, before then going to their respective finishing.

