120 film
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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 It was originally intended for amateur photography but was later superseded in this role by 135 film.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 survives to this day as the only remaining medium format, 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 The spool was originally made of wood with metal flanges, later all metal, and finally plastic.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 long.
Frame sizes
120 film allows several frame sizes, the most common being the 6 × 4.5 (56 × 45 cm), also called 645 format film.
| Name | Aspect ratio | Nominal size (mm) | Exposures |
|---|---|---|---|
| 6 × 4.5 | 5:4 | 56 × 45 | 15 or 16 |
| 6 × 6 | 1:1 | 56 × 56 | 12 |
| 6 × 7 | 4:5 | 56 × 70 | 10 |
| 6 × 8 | 3:4 | 56 × 75 | 9 |
| 6 × 9 | 2:3 | 56 × 84 | 8 |
| 6 × 12 | 1:2 | 56 × 112 | 6 |
| 6 × 17 | 1:3 | 56 × 168 | 4 |
Special-purpose panoramic cameras produce 6 × 12 or 6 × 17 cm exposures.
Both 6 × 7 and 6 × 4.5 enlarge almost exactly to 8 × 10 paper, for which reason their proponents call them "ideal formats". The 645 (6 × 4.5) in particular is the smallest, lightest, least expensive, and most popular roll-film design. Due to better control of frame spacing, modern 645 format cameras get 16 exposures per roll of 120.
Other similar 6 cm roll films
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. 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.
The 620 format was introduced by Kodak in 1931 as an intended alternative to the 120 format and is essentially the same film on a thinner and narrower all-metal spool (the 120 spool was made of wood at that time):
- 120 2.466" length, 0.990" flange, 0.468" core
- 620 2.468" length, 0.905" flange, 0.280" core
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.
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