Unknown elderly couple

In order to date a photo, it helps to see the entire front, including the type of edges, and the reverse side, whether it is colored, printed, etc. This photo did not come out very clear over the internet, but may have been about 1880. The vignetting of the subjects, gives a certain time frame, in itself. (That's redundant!) Of course that means they would probably be Edwin Allen's grandparents, based on ages.

Thanks for your comment! Good points. The back is plain brown, but shows the indented imprint of the decorative border on the front. The rectangle containing the two portraits has been glued or stuck(very securely) to the brown cardboard; the two portraits appear as though they had been attached separately to the rectangle, but they are part of the same paper--possibly rephotographed as a unit? It's strange. The woman's clothes I think might be older than the 1880s, but since elderly people often continued wearing fashions of previous decades, that doesn't really determine anything. I'm pretty sure these aren't Edwin's Riley grandparents, since I have a picture of Mary Hilliard Riley in her old age and it is not the same woman. Could be the Case grandparents, though--I know nothing about them. Thanks again.