They mention in the article that some of the old black-and-white Superman film is stored on glass as well - but what really amuses me is that (if I recall correctly) Superman HIMSELF stores film on glass (or long crystal shards) in the 1978 film that is the subject of this article. My sister and I used to pretend in winter that icicles were our VHS tapes and we’d put them in the snow to “watch” them.