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1952 Theatre Catalog, 10th Edition, Page 290 (254)

1952 Theatre Catalog, 10th Edition
1952 Theatre Catalog
1952 Theatre Catalog, 10th Edition, Page 290
Page 290

1952 Theatre Catalog, 10th Edition, Page 290

Common Causes of Damage to 35mm. Prints

Recommended Procedures for Reducing Film Damage And Prolonging the Useful Life of Release Prints

Fiim damage may be caused by various factors, among which are failure to provide adequate storage facilities, improper laboratory methods, inadequate inspection in the exchanges, careless handling in the projection room, and worn or imperfectly adjusted projectors. While it is sometimes difficult to determine the exact cause, each possible source of damage will be discussed. Also discussed are several beneficial practices which will do much to prolong the life of the film, such as making good splices, directions for determining the correct tension of projector parts and for making other projector adjustments.

A booklet entitled SFilm Mutilation and How to Prevent It" was published by the Eastman Kodak Company in 1924. This booklet proved to be so useful to exchange workers and projectionists that a revised edition entitled "Damage to 35mm. Release lPrints" was issued in 1945. It has been felt that a new discussion was needed to bring the old material up-to-date and to include the proper identification of the safety base materials now being used for release prints. Some of the older material contained in the previous booklets has been retained because a considerable amount of older projection equipment is still in use. Most of this information, however, is fundamental and applies to nearly all types of projectors.

THE FILM Structure

As an aid in understanding the factors associated with film damage and the measures which should be taken toward prevention thereof, it will be helpful to have a basic idea of the structure of the release print film. Motion picture release print film consists of a plastic base or support on which is coated a thin adhesive layer and one or more emulsion layers. The adhesive layer provides the necessary bond for holding the emulsion layer or layers firmly to the support. In the case of black-and-white release prints there is only one emulsion layer, but in the case of color release prints there may be several emulsion layers coated one on top of the other. In certain types of color films there may be adhesive layers and emulsion layers on both sides of the support. The emulsion layers usually consist of hardened gelatin which carry the silver or dye images in the picture area and the sound track.

The base or support of motion picture film, which is of standardized thickness, is made from cotton and wood cellulose. In former years, most motion picture film support was of the cellulose nitrate. type. In spite of the hazardous nature of the highly infiammable nitrate film and the safety precautions which were


Motion Picture Department, Rurhcxler, N. Y.

necessary in the handling and storage of this material, it was preferred over the older type safety film (cellulose acetate) for general theatre use because of its excellent physical characteristice. A great deal of research work has been done over the years in an attempt to make a more durable safety base film, and one whose characteristics would be equal to or better than those of the nitrate film. In recent years, such a safety support has been developed and this new support is fully suited to the rigid requirements of general theatre


BRIEF: Every year the loss through needless film damage runs into startling sums. There are several contributing causes to this damage, as will be pointed out in the pages that follow, and it is the purpose of this survey to give exhibitors and projectionists helpful facts with which they may not be familiar, and which will aid in reducing film damage.


use. This new support, known as high acetyl acetate or tri-acetate, has been thoroughly tested both in the laboratory and in the theatres and these tests show it to be superior in many respects to the nitrate material. All motion picture films now made by the Eastman Kodak Company are furnished only on this new type safety support.

Handling and Storage

One of the most important and basic causes of film damage and one which should concern everyone engaged in handling motion picture film is the failure to provide and maintain the proper storage facilities.

Damage may occur in a number of ways, such as from fire, earthquakes, fioods, fungus, etc. In many cases, the destruction is complete and may involve irreplaceable films. Very often, too, damage might be arrested or total loss avoided if frequent inspection of film were carried out. There are many aspects to the. subject of storage but all of these cannot be discussed adequately in the limited space provided here. Certain phases of the handling and storage prob lem are discussed briefly in the paragraphs which follow, however, because they are considered to be of such great importance during the period when the industry is converting from older nitrate base materials to the new safety type films.

Throughout the history of the motion picture industry a great deal of atten tion has been devoted to the subject of fire precautions and regulations connected with the use of motion picture films, particularly with respect to prevention of injuryito personnel and damage to buildings, but to a much lesser extent with respect to actual film damage. This has been proper and necessary because of the highly infiammable nature of the older nitrate base films. Over the years, safe practices in the handling and storing of nitrate film have been worked out by the cooperative efforts of various organizations, including the National Bureau of Standards, the National Fire Protection Association, the National Board of Fire Underwriters, the Underwriters' Laboratories, the Motion Picture Association of America, and the mm manufacturers.

It is highly important to recognize the fact that even though all Eastman motion picture film is now manufactured only on safety support, it will be some time before all the older nitrate film is out of circulation. Many release prints on nitrate base still remain in exchange vaults and are being circulated. It will probably be a number of years before such prints are destroyed or duplicated onto safety stock. A roll of film which is safety base at the outside might contain nitrate film in the interior of the roll. A print released on safety stock may later have replacements made on nitrate stock and be run on a projector not properly maintained for nitrate film. A laboratory which has been using safety stock for release prints for a period of time may suddenly switch to nitrate stock without announcement or warning. Even when no more nitrate film is being manufactured in the United States, foreign prints on nitrate stock may be imported. The danger of such practices is obvious.

Safety motion picture film requires no special precautions in handling and storage as far as its own fire hazard is concerned. The Underwriters Laboratories describe approved safety film as slowburning and state that ttHazards in use and storage are small, being somewhat less than those presented by common newsprint paper in the same form and quantity? Where safety film is used exclusively, only normal fire precautions are needed as in any ofiice building containing wood, paper or similar combustible material. Safety films, however, should be protected from excessive moisture or dryness by storing in tightly taped cans. Exposure to air of relative humidity exceeding 60 per cent before sealing must be avoided.

l/th're safety and nitrate films are both being used in theatres, the same regulations and precautions must be followed as if all the film were nitrate. For detailed instruction On safe practices

1952 Theatre Catalog, 10th Edition, Page 290