2 exposures in a single frame

2 exposures in a single frame. On the left, studio portrait of two young men wearing a white shirt. On the right, individual bust-shot portrait of a young man wearing a white shirt. No backdrop. Date of original material: [1953-54]. Size of original print/negative: 3 ½ x 2 ½ inches (2B). Format of original material: Glass plate black and white negative.