Before attempting any treatment, a thorough assessment of the film’s condition and stability needs to be made.
Some treatments, especially those using aqueous solutions, will damage unstable emulsions and bases.
Dirt and grease accumulate on the emulsion and base of a film through handling and static electrical charge. Dirt is not only a nuisance in blemishing the projected image but can cause physical damage during handling and can contain chemicals that will accelerate deterioration of the image or film base.
This chapter contains the following pages on cleaning: Spot cleaning, Dry dust back, Wet dust back, Particle transfer rollers, Solvents, Ultrasonic cleaning, Buffer roller cleaners and Aqueous cleaning.
Rewashing is not the same as cleaning a film, although some cleaning action occurs. Rewashing is designed to reduce surface blemishes such as minor scratching, mould damage and the effects of ferrotyping.
This chapter contains the following page on rewashing: Rewashing
On occasion film can adhere to itself with the reel to form a solid mass, known as blocked, that cannot be unwound without causing serious damage to the emulsion, to the base, or both. The film can become blocked by two known mechanisms: high humidity and tight wind and decomposition.