Nitrate film (cellulose nitrate film)

Nitrate film is historical photographic film with a cellulose nitrate base. It occurs both as photographic negatives and as motion picture film. The base supports the image layer; it is not the depicted subject itself. An old negative therefore needs identification through its material and context rather than the age of its image alone.

Clues and possible confusion

Edge printing such as “NITRATE” can provide a clue, but copied film may reproduce markings from the original. Production periods for different film bases overlap. Neither the subject’s date nor a single visible inscription is therefore sufficient for certain material identification. Cellulose acetate and polyester are other film bases and should not automatically be called nitrate film.

Deterioration can appear as yellowing, tackiness, brittleness or changes in the image layer. Such signs require professional assessment and are not a reliable home test. Do not use a burn test to identify film.

Preservation needs separate assessment

The National Library of Norway stores nitrate film and nitrate-based photographic negatives in a dedicated facility with special fire protection. Flammability and chemical instability mean that ordinary advice for paper photographs is insufficient. Consult a photograph conservator or an archive with relevant expertise before rehousing, digitizing or transporting the material. See also preserving old photographs.

Finding film in an estate

As a practical example, record information on an existing film box and where it was found, without starting to run the film through a projector. Mention film findings before an estate site visit and clearance planning. Historical motion picture film can be discussed with the National Library of Norway’s film collection. Contact the institution before any delivery. This does not guarantee acceptance or provide a home storage procedure.