Editing 9.5 mm film (section)

==Format==
The format makes use of a single, central perforation (sprocket hole) between each pair of frames, as opposed to [[8 mm film]], which has perforations along one edge, and most other film formats, which have perforations on each side of the image. The single hole allowed more of the film to be used for the actual image, and in fact the image area is almost the same size as 16&nbsp;mm film. The perforation in the film is invisible to viewers, as the intermittent shutter blocks the light as the film is pulled through the gate to the next frame.

The width of 9.5&nbsp;mm was chosen because three strips of film could be made from one strip of unperforated [[28 mm film]]. This was useful when duplicating films, because only one strip of 28&nbsp;mm had to be processed. When discontinued in 1927, 9.5&nbsp;mm strips were cut from [[35 mm movie film|35 mm film]].<ref>{{Cite web |date=2018-01-21 |title=9.5mm film (1922 - 1960) |url=https://obsoletemedia.org/9-5mm-film/ |access-date=2023-02-19 |website=Museum of Obsolete Media |language=en-GB}}</ref>

The projection system also incorporated a way to save film on non-moving titles. A notch in the film was recognised by the projector, which would then project the second frame after it for 3 seconds. By this method, 3 seconds of screen time was available for 1 frame of film, rather than the 42  frames required if the film was projected at the normal rate (which was 14 fps at the very beginning, then it became 16 fps). The same principle was used by the 'Agfa Family' system of [[Super 8 mm film|Super 8]] camera and projector in 1981 though to provide still images rather than titles.<ref>{{cite web|url=http://kameramuseum.de/0-filmkameras/agfa/family/family-home.html|title=Agfa Family|publisher=Kamera und Fotomuseum Kurt Tauber |language=de}}</ref>