Editing 120 film (section)

== Characteristics ==
[[File:Dancer photographed on medium format film.jpg|alt=A portrait of a dancer photographed in 6X9 format on 120 film|thumb|384x384px|A portrait of a dancer photographed in 6X9 format on 120 film]]
[[File:Boy in Mons Meg.jpg|thumb|Image shot on 120 film|256x256px]]
The 120 film format is a [[roll film]] which is nominally between 60.7&nbsp;mm and 61.7&nbsp;mm wide. Most modern films made today are roughly 61&nbsp;mm (2.4 inches) wide. The film is held in an open [[Bobbin|spool]] originally made of wood with metal flanges, later with all-metal, and finally with all-plastic. The length of the film is nominally between {{convert|820|mm|in}} and {{convert|850|mm|in}}, according to the ISO 732:2000 standard. However, some films may be as short as {{convert|760|mm|in}}.<ref>{{cite web | url=http://www.rogerandfrances.com/photoschool/ps%20how%20load%20120.html | title=Handling 120 film | first=Roger W. | last=Hicks | date=2006 | access-date=December 11, 2009| archive-url= https://web.archive.org/web/20091128014507/http://www.rogerandfrances.com/photoschool/ps%20how%20load%20120.html| archive-date= November 28, 2009 <!--Added by DASHBot-->}}</ref> The film is attached to a piece of backing paper longer and slightly wider than the film. The backing paper protects the film while it is wound on the spool, with enough extra length to allow loading and unloading the roll in daylight without exposing any of the film.  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.

The 220 format was introduced in 1965 and is the same width as 120 film, but with about double the length of film and thus twice the number of possible exposures per roll. Unlike 120 film, however, 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.  Because of this, 220 film cannot be used in  cameras that rely on reading frame numbers through a red window. 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 (optics)|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 (e.g. the [[Pentax 6x7]], [[Mamiya C220]] or [[Mamiya C330]]) while others will require different film backs e.g. the [[Pentax 645]] or [[Kowa Six]].

The specifications for 120 and 220 film are defined in the [[ISO 732]] standard. Earlier editions of ISO 732 also provided international standards for the [[127 film|127]] and 620 film formats.