Many early coaters that made paper used a brush or wick to remove excess baryta during the manufacturing process. On cold pressed papers, when coating hot emulsion, so much was absorbed by the paper that excess emulsion was "scraped away" by a brush or wick.
More commonly though for paper and film, a blade of metal was placed about 0.005" above the surface of the coating to remove any excess and to even out the thickness of the coating. This method would have been in use in the 40s. Some cases used an air knife or air brush to remove excess emulsion.
I hope this helps.