Something to note: the size of the final negative (and therefore the contact print) is not necessarily indicated by the size of the film used in the camera. I am familiar with 620 only, but I know that it was designed to provide 3 final image sizes, depending on the camera design.
I’m having trouble finding details or proof of this online, so I am drawing from memory (so I could be wrong).
The final neg size determined the number of images on a roll: 8, 12, or 16. the largest image was 2.25" x 3.25". I’m not sure the size of the others (you could calculate it). The backing paper had 3 sets of frame numbers in 3 columns, and the camera had a red window located in the right place to display only one of the number columns. AFAIK, no camera provided a choice; it was fixed at manufacturing time and the user wasn’t made aware of the multi-use for the film unless he developed it himself and saw the numbering scheme.
Wasn’t 620 used in the Roliflex 2.25" square format twin-lens cameras? Then the neg size would have been linked to the 12 frames per roll numbers. Or if the cam used 120 or 220 film, there would have been no paper backing, so another mechanism must have been used to register the next shot.
And the smallest neg size, 16 frames/roll, would be about 1.625" x 2.25", for the consumer cams where max frames would be more important than size/quality.
Are those dimensions correct?
I have a Kodak 620 1940’s-vintage unit, 8 shots per roll. You could either wind the film and use the red eye index, or use a gear-based counter that measured the movement of the film and stopped in just the right place for the next shot. This mechanical linkage usually worked, but if it didn’t, you wound too far, wasting precious and expensive film, so I learned not to count on it.
120 film that I used had paper backing, so you could handle the rolls in normal light. (Although direct sunlight not recommended). It was only stuck to the paper at the ends of the roll. The paper had numbers so that as you advanced the film, the frame number on the paper was visible in a tiny round window on the camera (on my twin-lens, at least). But oddly, my camera would click-stop when you had wound forward enough.
I think cheap Brownies used the same square 120 film?
I have a number of photos stored away somewhere from 1963 that seem to match the OP’s question. They were printed from 120 (2.25" square) but the pictures are not contact, they are about 3.5 square colour, with the serrated edge that seems to have been for nothing other than decoration back them. And… the date of processing is printed on the picture white border.
Current 120 film still has the paper backing with the frame numbers printed on it. Actually multiple sets of frame numbers since the same film is used for multiple film formats. Pretty much any “modern” medium format camera will automatically advance the film the required distance, so the numbers are not really needed in most cases.
By “currently” I mean that I still use them or see them being used (for real photography and not just for novelty). I hadn’t realized that there are no models still manufactured.
Oh, I don’t know there are no models of the others being manufactured. I would assume Mamiya and Hasselblads may still have film cameras. Those are definitely the three most used formats for 120 film, but I know some pro photogs who use 6x9 and 6x17 on occasion, but they are into all sorts of less usual bodies and lenses. I have a cheap Soviet 6x9 myself. It’s a weird compact accordion style foldable camera with terrible image quality.
I’ve got a maymia c330 with 2 lenses and a prism finder that I’ve not used for a few years sitting in the closet that I’d be willing to part with if anybody wants to shoot 120 or 220 film.
