‘Aspect ratio’ refers to the relationship between the width of an image and its height. From the earliest days of cinema, the standard ratio was 4:3. This was later accepted as the industry standard by the Academy of Performing Arts in Hollywood (the body that awards the ‘Oscars’), so it is sometimes referred to as the ‘Academy’ ratio.
When television began in the 1930s, it also adopted the 4:3 ratio as standard. After the Second World War when cinema started to move towards more wide-screen formats, television continued with the 4:3 ration. Most documentary films, whether they were made for television or not, also continued to be shot in a 4:3 ratio.
Eventually, in the 1990s, television also began to move towards more widescreen formats, and today 16:9 has become the standard both for television and for documentary film-making generally.
Throughout the period covered by The Silent Time Machine project, the standard aspect ratio for ethnographic film-making was 4:3.