I recall something Lisa said last evening, that "a contact print is a negative laid on paper exposed to light. Usually, it is the entire roll together."
Well, this contact print of Altgens6 can't possibly be real. It can't possibly have been made with the original negative. That's because the Altgens photo is a highly altered photo, and the original negative didn't look like this.
You see the sprocket holes of the film, top and bottom. And isn't that a "6" at the bottom? So, the images were numbered on the film, and this was the sixth one. Except, I recall reading somewhere that Altgens6 wasn't actually number 6 even though it is called "6".
But, regardless, this is definitely NOT the original negative; it was definitely fabricated at some point in time afterwards. So, how do we know what the original was dimensionally? Maybe this make-believe contact print was given the correct proportions after the fact. It is definitely make-believe because the Altgens6 photo was definitely altered, and altered a lot.