|Tintype, Carte-de-visite, 1870s|
It is too bad that this image is so dark because it is a fine example of the then state-of-the-art hearing aid technology. A colleague of ours uses a similar horn, and explains how each horn can be "tuned" to it's user, providing optimal amplification specifically to the frequencies in which the user is weakest.
Yes, it is significantly under-exposed, but she did leave the studio with it.
Despite the under-exposure, this is still a rare and interesting subject.