I just talked to the person who has this collection. The negative sizes are 3 1/2 by 5 1/4. I have no idea which camera would have taken these. He also has alot of 8 X 10 inch negatives. This person talked to his grandmother and got more information. His grandfather had a studio in New York before he got married. This was when he took the porno. There is a rumor in the family he photographed aspiring show business people before they became famous. I'm sure this is wishful thinking.