Hi Matthew
there is another way to do reversals that is in this meandering thread
https://www.photrio.com/forum/threads/reversal-print-processing-video-new-approach.153447/
it has to do with paper but with coated glass or metal or whatever, you can do it with any emulsion
I haven't used a camera and film in a while ( I slipped and fell in a deep rabbit hole and had tea with the queen )
but I have been planning on doing these with glass and metal and paper coated with emulsion... the trick is
to have the right concentration of citric acid you can use dollar store 3% peroxide and its a lot of fun..
I've also had loads of fun doing old school ferrotype reversals ( like Jason mentions ) and have attempted to
concoct my own reversal bleaching developer but as I mentioned I was having tea with the queen for a few years
and everything I had been planning on doing before was put on hold..
have fun! ( and don't listen to the hype that they aren't
authentic because they replaced that process by the early 1900s
the only difference is the developers &c were all proprietary so the recipes weren't all in the public domain )
John
ps. regarding how to display them, that's the million dollar question
. no clue !