I looked at the film again and have the feeling as I have thought before, that this is a combination of a wick to spread a thick layer of emulsion on the film (or paper) and then an attached blade or "wing" on the "wick" to level the coated emulsion and to even it out. In other words, a doctor blade.

This is due to the complexity of the coating head shown at the beginning of the film when they are hand coating some paper. It looks overly complex for a single application device and therefore I postulate two devices being used as I describe above.