When inspector Andra examines the photo negative with enlargement glass it is clearly visible that this is 35mm Ilford XP-2 film.
This film was not in production until 1980 when launched on Photokina, as B&W film that uses process C-41 intended for color film.
Also there is great chance that professional photographer in 1927 uses 120 film or plan film negative instead of 35mm.