Hi NMcS
Looking at the deterioration pattern around the edge of your photo, I'd hazard a guess that this is a Daguerreotype rather than a tintype, and it would therefore date from somewhere between 1840 and the mid 1850s - a very early photograph! Is the surface very shiny and reflective?
The surface of a Daguerreotype is very fragile and will scratch with the slightest touch, so be very careful.
Daguerreotypes are noted for their clarity and great detail, so I think if you could re-scan this picture at a high resolution without its frame (being very careful to place it gently on the scanner) and then post it again, you might get even better results as the image will then be in focus.
The frame, by the way, is not doing the photo any favours, and is partly the reason that it is deteriorating in that way around the edges. A photograph conservator would be able to give you advice about framing and storage if you were interested.
Cheers
Prue
