Dust, dirt and various types of oily deposit inevitably contaminate film when it is stored and used over many years. The deposits soon become visible when the film images are projected or scanned, but may also cause damage to the surfaces and particularly the emulsion.
Film can be cleaned in a two-stage process. First remove loose particles and bust by gently brushing the surface in a manner that causes the loose material to fall away from the film's surface. A suitably folded velvet or batiste cloth can be used to wipe the surface once loose material has been removed, but great care must be taken not to scratch the delicate emulsion surface.
Specialized solvent cleaners can be obtained to moisten cleaning cloths and may be useful to remove mould, fungi and mildew. However, it is recommended that the manufacturer of the film be contacted prior to cleaning valuable images in this manner. Water should never be used as this may destroy the emulsion. Isopropanol has been used over many years and may be available from pharmacies, but seek appropriate advice before starting work. Many of the film cleanliness problems can be avoided or at least substantially postponed by proper handling and storage. In general, the surface of a film should not be touched, and it should be stored in a clean, dark, cool and dry location.
Digital cleaning of film-based images is also possible but time consuming and hence expensive. The images are scanned, and all the dust particles, scratches and other blemishes are removed from the digital file. The cleaned image can then be reprinted onto film if necessary.