Although the images depicted are of different sizes, both of these miniatures are 105mm x 80mm. They were acquired several years apart but are both signed "A Birnbon" at the lower right.
They both appear to be on a very faint photographic base, with that of the younger man very hard to detect. This is where personal preference dictates whether a portrait is regarded as a painting or a photograph.
Some collectors decline to acquire miniatures on ivory with a photographic base, but they are a significant aspect of the history of portraiture and hence should be included in any collection intended to represent the social history of painted or photographic portraits.
Neither sitter is known, and little is known about A Birnbon. There is a c1899 reference at Inside the Hamlin Bank to an H Birnbon;
On Tuesday H. Birnbon, celebrated New York portrait painter, personally delivered to the Hamlin Bank & Trust Co., McKean county's oldest banking institution, in Smethport, a beautiful portrait likeness of the founder, the late Henry Hamlin, done in oil. The large painting presents a likeness of McKean county's pioneer banker which is striking in its fidelity to detail. The picture will occupy a commanding position on the wall.
It seems likely that this refers to the same artist, or else a close relation. The name Birnbon is very rare, and one wonders if the artist changed it from Birnbaum at the time of anti-German feeling during World War I. 1041, 1445