120 film

Most modern films made today are roughly 61 mm (2.4 inches) wide.

The film is held in an open spool originally made of wood with metal flanges, later with all-metal, and finally with all-plastic.

Frame number markings for three standard image formats (6×4.5, 6×6, and 6×9 [4:3, 1:1, and 2:3 aspect ratios]; see below) are printed on the backing paper.

(cm) †User selectable on newer cameras, if a roll is only partially used then a "kink" may appear in the film where the roll touches rollers in a film back magazine and this may end up on a frame; this is not a problem when 15 exposures are used as the gaps between exposed frames is larger, nor if the camera is not used intermittently.

The 6×7 frame enlarges almost exactly to 8×10 inch paper, for which reason its proponents call it "ideal format".

Cameras using 120 film will often combine the numbers of the frame size in the name e.g. Pentax 6×7 (6×7), Fuji 617 (6×17), and many 645s (6×4.5).

1 Folding Pocket Kodak, as the overall length between the outside of the flanges is too long to fit the width of the film chamber.

The 620 format was discontinued by Kodak in 1995, but it is possible to rewind 120 film onto a 620 spool in the darkroom for use in 620 cameras.