3.21 Tears
3.22 Perforation Damage
3.23 Scratches
3.41 Nitrate
3.42 Acetate: Vinegar Syndrome
3.43 Color Fade

Film is subject to three main categories of deterioration: mechanical, biological, and chemical decay. Causes of damage and decay will be discussed in this section, and the main techniques to control film deterioration will be identified.

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Although the condition of a reel of film is not necessarily dependent on its age, it is often helpful to know how old a piece of film is. One method for identifying the age of a film is to look for its manufacturer's date code. Kodak prints a series of small shapes along the edges of its film. These codes identify the date the film was manufactured, but remember that sometimes it may have been several years later that the film actually went through a camera. Also be aware of the fact that Kodak's codes run in twenty-year cycles, so the code for 1955 is the same as 1975. You will also have to look at the image and use other clues to determine its age. Finally, if you are looking at a copy and not the original, determine which series of codes you are reading, as you may be able to see more than one generation. Older codes may have been printed through in the laboratory printing process. Note all codes, and use the most recent one to determine the age of the piece of film you're looking at.

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3.21 Tears
Tears and breaks are usually the result of mishandling of film during winding or projection, or of old splices coming undone. All breaks, tears and weak splices need to be repaired with cement or tape splices.

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3.22 Perforation Damage
Another common type of damage is torn perforations (perfs). This is usually caused by improper threading of the film in the projector, and is usually found at the beginnings and ends of reels or after a bad splice. The best way to avoid further perforation damage is to always be sure to use sufficient leader (at both the heads and tails of reels). Repair all faulty splices, thread the film carefully in a clean, properly lubricated projector, and do not attempt to project shrunken or brittle film.

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3.23 Scratches
Either side of the film may be scratched by contact with dirt or worn rollers in the film path during projection. Scratching and abrasions can also occur outside of the projector if film is wound too tightly or loosely. Scratching may have occurred at the lab, in the camera, or during the editing process. Never pull the end of a reel of film to tighten it up on the reel or core. This is an easy way to scratch your film. While there are film treatments to "rejuvenate" films by applying protective coatings or lacquers, we do not recommend this because possibly harmful chemicals are involved. Base-side scratches can be minimized during the duplication process (either film-to-film or film-to-video telecine) by the use of the wet gate method, in which the film passes through a liquid solution that temporarily fills in the scratches so they do not show in the resulting copy.

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Mold, Mildew, Fungi
There are types of damage that can occur even while the film remains in storage. Improperly stored films, especially those in hot and humid climates or damp locations such as cellars or garages, are prone to attack by mold, mildew and fungus. These organisms can cause severe damage to the emulsion, and while they generally attack the film from the edge, they can easily make their way into the roll, sometimes resulting in dull spots or feathery tendrils on the image. Providing proper storage minimizes the risk of biological decay. This might be achieved by just avoiding sustained high humidities, typically during the summers, and by improving ventilation.

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Film components such as film supports (e.g., nitrate and acetate) and color dyes are inherently subject to chemical deterioration.

3.41 Nitrate Decomposition
Cellulose nitrate film base is prone to chemical decay over time. The condition nitrate films are in today is a direct result of the conditions under which they were stored, as well as how they were manufactured.

Nitrate decay is described in terms of 5 specific stages. These descriptive stages are a widely recognized standard.

Stage 1: Film has an amber discoloration with fading of the image. Faint noxious odor. Rust ring may form on inside of metal film cans.
Stage 2: Emulsion becomes adhesive and the film tends to stick together during unrolling. Faint noxious odor.
Stage 3: Portions of the film are soft, contain gas bubbles, and emit a noxious odor.
Stage 4: Entire film is soft and welded into a single mass, the surface may be covered with viscous froth, and a strong noxious odor is given off.
Stage 5: Film mass degenerates partially or entirely into a shock sensitive brownish acrid powder.


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3.42 Acetate Decomposition: Vinegar Syndrome
Acetate base film is subject to the so-called vinegar syndrome. The term 'vinegar syndrome' is taken from the distinct odor that is given off by deteriorating acetate film. Vinegar syndrome results from a chemical reaction that takes place at the molecular level that can cause serious and irreparable damage to film. When combined with moisture, heat, and acids, the plastic support in the film begins to release acetic acid. The process is an autocatalytic one, meaning that once the degradation begins it starts to 'feed upon itself' and the deterioration process begins to snowball. When film reaches its autocatalytic point the acetic acid released by the film grows exponentially, and with it the potential problems for the film. Climate is an important determining factor in the deterioration because humidity affects the amount of water absorbed by the film and heat supplies energy for the chemical reactions. Even more important is the "micro-environment," a term used to describe the conditions inside the film can. Vinegar syndrome appears to be contagious, so any film suffering from it should be stored apart from "healthy" reels.

The vinegar smell is the most obvious indicator of decaying acetate film, but it is by no means the only one. The condition of the film can be evaluated by using acid detector strips (e.g., IPI’s A-D Strips); this approach provides an objective way to determine the state of preservation of the materials and their needs to be further stabilized. White powder on the edges of the film may indicate plasticizers loss. Because of the molecular breakdown of the plastic base, in advanced stages of deterioration the film becomes brittle and shrunken. Films with shrinkage of more than 1% could be damaged by projector mechanisms, so should not be projected. [See section 5]
There are techniques for re-dimensioning film (restoring it to a less-shrunken state), but these are temporary measures that can permanently damage the film and should only be done in a lab situation as a last-ditch method to enable a new negative or print to be made.

Acetate Decomposition—Advanced Stages of Decay
The typical pattern for acetate decay is:

1. Vinegar odor
2. Shrinkage
3. Cupping: the film retains a curve. It will not lie flat, but instead appears wavy.

4. Crazing: the emulsion cracks and the image appears as a crazy mosaic.

5. Appearance of white powder on edges (from binder deterioration, this is the plasticizer separating from the film).
6. Film becomes square on reel [Illustration].
7. Film is no longer flexible and the emulsion flakes off from the base.

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3.43 Color Fading and Decomposition
Color fading and other forms of chemical decomposition are usually the results of inherent problems in the manufacturing of the film, bad processing or poor storage conditions over the years. Generally there is nothing that can be done to reverse the process of color fade. However, you can stop further damage to the film by moving it into good storage conditions (see section 8).

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