126 is a film format used for still photography. The original film designated "126" was a roll film introduced by Kodak in 1906, for images 4 1/4 x 6 1/2 inches. That film was discontinued in March, 1949. In 1963, Kodak introduced a new film, encased in a plastic cartridge, for which they re-introduced the "126" designation. The image format is fixed by the cartridge at a square 28 x 28 mm, which is reduced to 26.5 x 26.5 mm by masking. The width of the film is the same as 35 mm, but the perforation basically consists of just one registration hole per image:

The film is housed in a dual spool plastic cartridge that also registers the film. The film was available in 12 and 24 image lengths, but today it is only available in 24-image rolls. Like the 120 format, there is a continuous backing paper, and the frame number and type is visible through a window at the rear of the cartridge. The film does not need to be rewound, and is very simple to load and unload.

The 126 cartridge was introduced by Kodak in 1963 under the brand name Kodapak, together with the Instamatic camera. Around ten million cameras were made, but with a few notable exceptions, the format were never really used for anything but fairly simple amateur cameras. Kodak and others discontinued the format at the end of December, 1999. Ferrania in Italy is still producing 126 cartridges of ISO 200 color print film.

International standard: ISO 3029