What does it look like?

A roll of 35mm cellulose nitrate motion picture film in excellent condition
© The Board of Trustees of the Science Museum

A roll of 35mm cellulose nitrate motion picture film in very deteriorated condition
© The Board of Trustees of the Science Museum

Nitrate film yellows and curls as it deteriorates, and it produces a strong acrid odour. The smell of nitrate film deterioration can be distinguished from acetate film deterioration known as vinegar syndrome after its characteristic vinegar odour. Otherwise, to the untrained eye, nitrate film is often difficult to distinguish from other non-flammable photographic film.