What is this thing?

I know a lot about old photographic processes, but this one's got me stumped.  The scanner wasn't able to pull a usable image, so I'll have to describe it as best as I can.  It's a negative.  At least I think it is.  At least it's a very thin, flexible medium similar to modern film.  It's held in a kind of metal frame, open at the top and bottom, with side edges that hold the film tightly  in place.  There's no glass or any other clear medium over the thing, although I have no idea if it's still complete.  My best guess is that it's meant to be like a tintype or ambrotype,  a neg that looks positive because it's placed on a black background.  If that's the case, it didn't work.  Also, it's curved.  And of course, the big question, Is this something that was once a known, widely used process, or is it the failed experiment of some basement tinkerer?  And the image itself, it's a man in a uniform of some kind.  It's hard to make out, but I'm thinking more police than military.  So, should I take it apart and try and print the thing, or leave it as is?  I'm leaning toward leaving it as is, but I'm not wedded to that.  It would help if I actually knew what it is.