A cellulose diacetate film base. Introduced before World War I for home movies, diacetate base was more expensive and unpredictable than nitrate base and failed to gain acceptance in professional 35 mm. A cellulose nitrate film. Cellulose nitrate support or base was used in the manufacture of 35 mm. Nitrate base film is no longer manufactured.
Nitrate film is highly flammable.
It does not meet the ANSI requirements for safety base film. A combination of nitrate base and safety base film. The use of mixed bases, spliced together, can be found in microforms from the early 1950s. An item that does not have a film base. Such items are primarily microforms on a reflective rather than transparent base.