Thank you to Gloria Conti, conservator working in Scotland who found this Italian newsreel from 1938 titled Le tante utilizzazioni della pelle del pesce. The film shows the processing of fish skins into various products. Gloria provided a translation of the brief narration below.
The many uses of fish leather
In Germany fish leather is very in vogue. After being tanned, worked, dried, and handled with meticulous patience, it can be used to make many things like we see here: shoes, handbags, gloves, belts, and even to bind books.Thank you Gloria.
The imagery looks like the photos used to illustrate Franz Weisse's article "Fischhaut - Fischleder - Fischpergament" published in Das deutsche Buchbinderhandwerk, Vol 2, Nr 9, 1938. I described that article and shared some of the images in my post "Fish Skin - Tanned Fish Skin - Fish Parchment."
Perhaps the footage and images were taken together?
My question, are there articles and references in the bookbinding literature outside of Germany that describe using fish for binding...?