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Medium format film 220 or 120 is 60mm wide, no sprocket holes, former does around twice the images of the latter, has opaque backing on leader and trailer only, 120 film has full length backing.
Camera design fixes the final negative image size.
Example... a discontinued model...
Fujifilm Pro GX680
Fuji on the GX680 said:
type of film:- Roll film 120 / 220, instant film FP 100 C (or corresponding type) with instant cartridge
photo format 6x8 [cm]
6x4.5, 6x6, 6x7 [cm] using format masks (available as an option)
Thinking about it, I used a Balda folding camera with Baldanar lens using 120 film, way back in the 60's. The camera produced two and a quarter inch square pix... So that 57.2 mm square image would very likely have been your 6x6cm format !! Good camera.
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