The literal interpretation of the title of this thread, "METERING WITH FILM" is carried out as follows:
1) load unknown film into camera
2) expose a scene at varying aperture/shutter speed combinations
3) record exposure for each scene
4) process the film
5) select the lightest image that has detail in the shadows
6) look back at the exposure used to expose that negative
7) use that same exposure the next time you encounter a similarly illuminated scene