I have no constructive input to this conversation; only wonderment. I'm trying to wrap my mind around the enormity of a machine that would apply a dozen layers of emulsion on the film base. I can only conclude that the master roll goes through multiple passes, drying, and re-rolling on the machinery, that it is not done in a single pass, or the machine would be a mile long. I also wonder if the liquid emulsion is applied by rollers like a printing press, or if the base is run through the machine with a bead of liquid, whose viscosity is carefully controlled to draw ann appropriate amount of liquid out of the bead, hence controlling thickness of the emulsion layer.
I also wonder how long of a distance must the wet film travel before it is hardened enough to roll on the other end.