I’ll kick it off with l, arguably, the best one I own. It is the original, 1 of 1 glass plate negative of Captain Lou in college(1923).
As a photography fan, I believe there is still a huge upside as far as investment of original photos. Although on the radar, they are still undervalued IMO. Mostly because there is a relatively small group of collectors(vs say cards). I believe when PSA implements a registry of any kind, the fireworks will fly. They are on their way….
The negatives, however, are further back. They are in their infant, infancy.

they are as rare as it gets for any one image- 1 of 1. They produce the highest end prints(IF in good shape). And they are totally untapped as it relates to mainstream hobby collecting and authentication. There is a huge opportunity for collectors/investors as well as an authentication outfit.
Negatives are just so cool and would love to see others post here who also enjoy them. I am totally hooked and believe in them. They are not for the faint of heart. However, if you start, it’s hard to stop. . They are historical relics and it’s amazing to say.. “i own the actually original, 1 of 1 negative of that image. “ “ I am going to start my own Archive.” I think the sky is the limit.
I know I know.. they are hard to display and it is scary that they might break. Anything else?
I will be making 1 of 1 very high end prints of each of my best pieces which i will display. Also, i have looked into getting dupes made of the originals just for displaying purposes along with the photo(keep the original locked away). This can be done at every medium.. glass, acetate, slides etc.
Anyone else love abs collect this stuff? If so, would love to hear your thoughts and see your examples. Let’s have some fun(if you want) and put funny watermarks on but still allow the beautiful image to be appreciated. I will start on my following examples.
As always, excuse and autocorrects /fat fingers as I’m on the fly on my phone.