Adding to my last post, 16mm film was also used for sending copies of UK programmes to other countries. Notably in the anglophone commonwealth. Some programmes, believed lost, have turned up on 16mm film in places like Nigeria.
In a very few cases, where a colour programme has been telerecorded from a monochrome monitor, the subcarrier dot crawl pattern has been sufficiently well resolved to convert the film back to colour.
There was also a heroic attempt to reconstruct a film that had fused into a solid mass. Not sure if it was 16mm or 35mm. ISTR the solid lump of film was sliced into sections small enough to fit in a high resolution industrial CT scanner. The silver in the emulsion shows up well. Then a massive computing job to piece everything back together. This seems like Dead Sea Scrolls territory. Scroll down to "the Salvation of British Comedy":
https://hackaday.com/2018/09/20/the-...f-ct-scanners/