The aspect ratio 4:3 was used for 35 mm films in the silent era. It is also very close to the 1.375:1 Academy ratio, defined by the Academy of Motion Picture Arts and Sciences as a standard after the advent of optical sound-on-film.
The 4:3 format was utilized for 35 mm films during the silent era. It shares a striking resemblance with the 1.375:1 Academy ratio, which was adopted as a standard by the Academy of Motion Picture Arts and Sciences after the introduction of sound technology.