Double studio bust-shot portrait on one negative

Double studio bust-shot portrait on one negative. On the left, a man and a boy standing next to each other in white shirts. On the right photo, a portrait of the same boy alone; he faces and looks the camera. No backdrop. Date of original material: [1952-53]. Size of original print/negative: 3 ½ x 2 ½ inches (2B). Format of original material: Glass plate black and white negative.