Cameras for still photography were developed to take advantage of the flexibility and length of 35mm film—initially introduced for recording motion pictures—at the turn of the twentieth century. A large number of exposures could fit on each length of film and could be rolled tightly and compactly in the camera. In 1913 the frame size for still photography was set to 24×36 mm (the modern day full-frame format) and the first 35mm cameras were made available to the public with black-and-white film.
Although color photography is almost as old as black-and-white photography, it did not become widely available to the public until 1936 when Kodak introduced the first modern color film, Kodachrome (ASA 10), a 35mm positive slide film. Although it cost $3.50 a roll (the equivalent of $50 today), it became the first commercially successful amateur color film.
In addition to being more expensive than black-and-white film, color film was very slow and often required the use of large and inconvenient flash bulbs. To get an idea of the disparity in film speed, Kodak introduced TRI-X, a high-speed 400 ASA 35mm black-and-white film in 1954. The comparatively slow Kodak High Speed Ektachrome 160 ASA became the fastest color film on the market when it was introduced five years later in 1959.
Kodachrome II (ASA 25), a faster (but still not particularly fast) and more versatile version of the original Kodachrome, came out in 1961, and although it made color photography more appealing to the general public, it still tended to be reserved for travel photos and special occasions.
By 1970, prices had come down, film sensitivity had been improved, convenient electronic flash units were replacing flash bulbs, and color had become the norm for snapshots. It is testimony to the success of 35mm film that it remained, by far, the dominant film format until the advent of digital photography at the turn of the twenty-first century. It remains the most popular and accessible film for analog photography, although others are still available, including 120 film for medium format cameras, and large format sheet film.