Photographic Films:

Photographic Films:

The first flexible films, dating to 1889, were made of cellulose nitrate, which is chemically similar to guncotton. A nitrate-based film will deteriorate over time, releasing oxidants and acidic gases. It is also highly flammable. Special storage for this film is required. It is highly explosive and should be kept at low temperatures, in sealed bags, in fireproof vaults.
Nitrate film is historically important because it allowed for the development of roll films. The first flexible movie films measured 35 mm wide and came in long rolls on a spool. In 1920s, using this technology, 35-mm roll was developed for the camera. By the late 1920s, medium-format roll film was created. It measured six centimeters wide and had a paper backing making it easy to handle in daylight.