[mejutoco]

A similar effect was used in analogue photography by putting some stockings on top of the lens. IIRC it is called "flu effect", which seems to be, unfortunately, ungoogleable.

[sva_]

It seems to be referenced on the web, just not as "flu effect"

https://www.digitalcameraworld.com/tutorials/home-photograph...

https://www.cnet.com/tech/computing/diy-photo-filters-with-e...

[colanderman]

Such techniques generally are termed "gobos", i.e. "go-betweens".