120 film
120 is a film format for still photography introduced by Kodak for their Brownie No. 2 in 1901. It was originally intended for amateur photography but was later superseded in this role by 135 film. It and its close relative, the longer 220, survive to this day as the only remaining medium format film, popular with professionals and amateur enthusiasts.
The 120 format is typical of roll film. The spool was originally made of wood with metal flanges, later all metal, and finally plastic. Frame number markings for the three standard image formats are printed on the backing paper. The film is 72 cm (28.3 inches) long.
Frame sizes
120 film allows several frame sizes.
| Name | Aspect ratio | Nominal size (mm) | Exposures |
|---|---|---|---|
| 6 × 4.5 | 1.35:1 | 56 × 41.5[1] | 15 or 16† |
| 6 × 6 | 1:1 | 56 × 56 | 12 |
| 6 × 7 | 1.25:1 | 56 × 70 | 10 |
| 6 × 8 | 1.37:1 | 56 × 77 | 9 |
| 6 × 9 | 1.50:1 | 56 × 84 | 8 |
| 6 × 12 | 2.1:1 | 56 × 118 | 6 |
| 6 × 17 | 3:1 | 56 × 168 | 4 |
| 6 × 24 | 4:1 | 56 × 224 | 3 |
†Due to better control of frame spacing, modern 6×4.5 format cameras can fit 16 exposures onto a roll of 120
The 6×7 frame enlarges almost exactly to 8×10 inch paper, for which reason its proponents call it "ideal format". 6×4.5 is the smallest and least expensive roll-film frame size; equipment to take photos in this size is also the lightest.
The wide 6×12, 6×17 cm, and 6×24 frames are produced by special-purpose panoramic cameras. Because of the need to cover such a wide piece of film, some of these cameras use lenses intended for large format cameras.
Cameras using 120 film will often combine the two numbers of the frame size in the name e.g Pentax 67 (6×7), Fuji 617 (6×17), and many 645s (6×4.5).
Cameras known to use 120 film
Other similar 6 cm roll films
The 105 format was introduced by Kodak in 1898 for their first folding camera and was the original 6 × 9 cm format roll film. The 117 format was introduced by Kodak in 1900 for their first Brownie camera, the No.1 Brownie, 6 × 6 cm format. These formats used the same width film as 120 film, but with slightly different spools. The 105 spool has a much wider flange, similar to the 116 spool. The 117 spool is slightly narrower than the 120.
Although mostly used by Kodak cameras the 620 format, introduced by Kodak in 1931 as an intended alternative to the 120, became very popular. It is essentially the same film on a thinner and narrower all-metal spool (the 120 spool core was made of wood at that time) :
- 120 2.466" width, 0.990" flange, 0.468" core
- 620 2.468" width, 0.905" flange, 0.280" core
Hence the 620 is sometime referred as "small hole" 6x6 or 6x9 as opposed to 120 "large hole". The 620 format was discontinued by Kodak in 1995, but it is possible to rewind 120 film onto a 620 spool in the darkroom to enable use of 620 cameras. According to Kodak, the narrower metal spool allowed building smaller cameras. Nonetheless the 120 format cast-metal bodied Voigtländer Perkeo remains smaller than any 620 format camera.
The 220 format was introduced in 1965 and is the same width as 120 film, but with double length (144 cm) film and thus twice the number of possible exposures per roll. Unlike 120 film, there is no backing paper behind the film itself, just a leader and a trailer. This results in a longer film on the same spool, but there are no printed frame numbers. Moreover, it cannot be used in unmodified old cameras that have a red window as frame indicator. Also, since the film alone is thinner than a film with a backing paper, a special pressure plate may be required to achieve optimal focus if the film is registered against its back side. Some cameras capable of using both 120 and 220 film will have a two position adjustment of the pressure plate while others will require different film backs (e.g Mamiya C220, Mamiya C330, Pentax 645).
See also
References
- ^ 645NII specifications, Pentax.