I'm forever on the hunt of early photographs of folk art paintings, and photographs of photographs, too (representations of representations, emblematic of the emergence of new modes of representation, and also emblematic of the want to preserve pieces of the past and carry them forward) and I believe this is both--a tintype copy I'd guess of an daguerreotype or ambrotype of a painting of a young child. [The other possibility I suppose would be a tintype of a portrait miniature.) Dark and appearing almost as if intentionally scratched, with at least a good part of that scratching seeming to me embedded in the image rather that on the surface of the tintype. With clear oval toning from where previously framed/cased, though again a bit hard to tell at which stage in the life of the image! Wonderfully intense and also feeling full of mystery--just the sort of thing to trigger obsession.
2 9 /16” x 2”. Dark, as noted--I've photographed it in a few different lighting situations to try to give a good sense. Surface is smooth and flat, with no bends or dings at all.