SMPTE RP 131-2002 Storage of Motion-Picture Films《电影胶片的储存》.pdf

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1、SMPTE RECOMMENDED PRACTICE RP 131-2002 Revision of RP 131-1994 Storage of Motion-Picture Films Page 1 of 8 pages Introduction It is impossible to estimate the value of the motion-picture films that have been produced during the life of this industry. These films are a rich resource representing both

2、 historical events and a unique art form. When one realizes that a major portion of motion pictures and television programs produced in this century has been lost or destroyed already because of improper storage, the importance and urgency of preserving those still existing are underscored. The conv

3、ersion of motion pictures and television programs to color films has raised concerns about the long-term stability of the dye images. Attention to this question has contributed to a general renewal of interest in the preservation of all motion pictures, both black-and-white and color. Long-term pres

4、ervation of almost any human artifact is a challenging and costly effort. There are no simple, inexpensive methods that are satisfactory for this purpose. Furthermore, extended-term storage, particularly, implies that the preserved artifact is rarely removed from storage for examination. Proper stor

5、age of motion-picture films requires that a sufficient number of working copies be available at the time the original films are put into storage. Proper storage is not a new subject and a variety of documents on the preservation of motion-picture films already exists. These include ANSI and IS0 stan

6、dards, an EBU technical bulletin, a report of the International Preservation Commission of FIAF, several SMPTE, BKSTS, and IS e.g., LE-100 indicates that information can be retrieved after at least 100 years storage. 3.8 life expectancy (LE): The length of time that information is predicted to be ac

7、ceptable in a system at 21C and 50% RH. 3.9 medium-term storage conditions: S t o r a g e conditions suitable for the preservation of recorded information for a minimum of 10 years. 3.10 safety photographic film: Film that meets the specifications with respect to hazards from fire as defined in ANSV

8、NAPM IT9.6. 3.11 storage housing: A physical structure supporting the film enclosures and may consist of drawers, racks, shelves, or cabinets. 4 Storage and handling In order for motion-picture film to be protected, it must be properly stored and handled throughout its life. For convenience, the lif

9、e cycle has been divided into three sections: prior to processing, after processing, and in archives. Although processing is not covered in this practice, it is imperative that black-and-white films be properly washed to prevent stains, etc., and that color films be properly washed and stabilized to

10、 minimize stains, dye fading, etc. The manufacturers processing recommendations should be carefully followed for both black-and-white and color films. Specifications for the stability of black-and-white silver-gelatin imaging media (film) are stated in ANSVNAPM IT9.1. Page 2 of 8 pages RP 131-2002 4

11、.1 Prior to processing 4.1.1 Environmental conditions During manufacture, the raw stock is equilibrated at the appropriate relative humidity, placed in vapor-proof containers (taped cans or foil bags), and sealed. The containers should be kept sealed until the film is to be used (exposed) to maintai

12、n the proper moisture level in the film during pre-exposure storage. High relative humidity should be avoided to prevent rusting of cans and deterioration of labels, tapes, and cartons. The raw stockshould be kept at 13OC (55F) or lower until exposure. If the stock must be kept for periods longer th

13、an six months, it should be stored at -1 8C (0F) or lower. Once the film is exposed, it should be processed as soon as possible. If the film must be stored after exposure and prior to processing, it should be kept at -18C (0F) to prevent any loss of the latent image. Raw stock must also be protected

14、 against harmful gases, such as hydrogen sulfide, sulfur dioxide, and peroxide, and against radiation. Since some gases may slowly penetrate the tape which seals the cans, even unopened raw stock should not be stored in an area where harmful gases are present, even in small amounts. As the speed of

15、motion-picture camera film is increased, its sensitivity to radiation (X-rays, gamma rays) is increased. Some stone aggregate in the concrete used to build film storage rooms can emit sufficient radiation to fog these sensitive films. All storage rooms should be measured for their radiation levels p

16、rior to being used to store raw stock. 4.1 2 Storage enclosures Raw stock should be kept in the original manufacturers container until exposed. After exposure, it is suggested that the film be placed in the original container and retaped. The time between taking the film out of its container and rep

17、lacing it in its bag and container should be kept as short as possible. , 4.1.3 Storage rooms As long as the new stock remains sealed in its original container, its moisture content will not be significantly affected by the RH of the storage room. However, RH above 60%, can damage labels and cartons

18、, iron will rust, and fungi will grow. Provisions should be made against damage by water or exposure to harmful gases. 4.1.4 Handling techniques Raw stock or exposed unprocessed film should be handled as little as possible, and great care should be taken to keep all cameras, changing bags, winding e

19、quipment, etc., scrupulously clean. If the unexposed, unprocessed film is stored at 13OC (55F) or lower, the film shall be allowed to warm up to room temperature before opening the can to prevent moisture condensation which may lead to sticking or spotting of the film. When film rolls are cold, ther

20、e is greater contraction in the radial direction than in the circumferential direction which leads to loose cores, and loose winds. Handling film in such a condition can result in stepped rolls or loss of roll integrity. These eff ects can create camera noise and carnerdprinter loading problems. 4.2

21、 After processing 4.2.1 Environmental conditions Processed film is no longer light sensitive, but it is still subject to change over a period of time. After processing and prior to placing the film in its final storage location, processed film should be handled carefully and prepared for storage. Wh

22、enever possible, film selected for long-term storage should contain a minimum of splices. The film should be handled in an air-conditioned area where temperature and relative humidity are monitored and controlled. Long periods of high temperature or high or low humidity should be avoided. High tempe

23、htures can hasten the fading of dye images and cause film shrinkage and physical Page 3 of 8 pages RP 131-2002 distortions. Low humidity can cause brittleness, while high humidity can accelerate dye fading and base decomposition, and cause mold and bacteria growth. 4.2.2 Storage enclosures Motion-pi

24、cture films are normally wound on cores if they are preprint materials and on reels if they are release prints. The rolls should not be wound with high tension, nor should they be loose enough to allow movement of the film within the roll ( 24-oz tension for a 1000-ft roll is satisfactory). 4.2.3 St

25、orage rooms If possible, rooms and areas used for film storage should be located near the areas where the film is being used. Provisions should be made against damage by water or other associated hazards. 4.2.4 Handling techniques Proper handling of film, whether unexposed, exposed, or processed, is

26、 critical. Cleanliness and good house- keeping procedures are essential if dirt or the results of dirt are to be kept out of the final screen image. Whenever possible, film should be handled in a work area provided with positive pressure and a filtered, conditioned air supply. Any equipment or surfa

27、ce that may come into contact with the film should be cleaned frequently. The film itself should be handled as little as possible, only by the edges, and with gloves to protect it. Smoking should never be permitted in a film-handling area. 4.3 In collections 4.3.1 Environmental conditions After moti

28、on-picture film, whether print or preprint, has been assigned to a collection, it should be stored under controlled relative humidity and temperature conditions. The relative humidity and temperature selected depend on the length of time the film is to be preserved (see table 1). The recommended con

29、ditions are the same as those in ANSVPIMA IT9.11. The effects of environmental conditions on the storage of motion-picture film are presented in annex A. Additional information is available from manufacturers of motion-picture film. Table 1 - Maximum temperatures and relative humidity ranges for ext

30、ended-term storage Relative humidity Maximum range temperature 20-50 2 20-30 7 Sensitive layer Base type % OC Black-and-white silver-gelatin Tri acetate 20-40 5 Black-and-white silver-gelatin Polyester 20-50 21 Color Triacetate 20-50 -1 o Color Poly est er 20-40 -3 20-30 2 Page 4 of 8 pages RP 131-2

31、002 4.3.2 Storage enclosures The recommendations in this clause are taken from ANSVPIMA IT9.2 and 4.1 of ANSiiPIMA iT9.11. Refer to those documents for additional information. Motion-picture film is wound on reels or cores and stored in roll form. Rolls should be wound emulsion in and title in, but

32、not under extreme tension. Rolls mounted on cores, particularly those longer than 500 ft, should be stored flat (horizontal) unless the core itself is carried on a horizontal spindle to prevent the lower part of the film from supporting the load of the core. If such rolls are on spools which have fl

33、anges, a spindle is not required since the flanges support the weight of the roll. Storage enclosures for motion-picture films may be noncorrosive metal, plastic, or acid-free board. Use of steel for reels is permissible provided that the reels are well protected by enamel, tinning, or other corrosi

34、on-resistant finishes. Preferred plastic enclosure materials (cans, cores, and reels) are polyolefins (polypropylene). Accept- able plastic materials are polystyrene and polyacrylates. Polyvinyl chloride is not recommended for this use. Suitable containers are those with flip-top, telescoping, or sl

35、ip-type lids. The materials used shall meet the same requirements as those for cores and reels. Closed containers are not necessarily air tight and may give limited access to ambient air. Therefore, if they are used, the humidity of the ambient air must not exceed recommended limits. Sealed containe

36、rs can be used as an aitemative method for providing protection from high or low humidity in a film storage area where only the temperature is controlled. However, researchers have found that cellulose acetate film base is subject to a deterioration phenomenon called vinegar syndrome. This hydrolyti

37、c reaction is acid catalyzed and auto catalytic. Recent studies with sealed containers indicate that adding silica gel (a desiccant) or a zeolite commonly called a molecular sieve to the container will reduce the moisture content of objects inside the container and absorb acetic acid generated by th

38、e degrading film base. Removal of the moisture and the acetic acid can slow down the degradation and can also impart additional dye stability to color films. However, once the reaction has begun, the film should be separated from unaffected material and removed to another area until it can be duplic

39、ated, preferably on polyester base material. Pressure-sensititve tape, if needed, shall be free from peroxide, and pass the photographic activity test in ANSWNAPM IT9.16. Pressure-sensitive tape shall not be used in contact with the film, other than on the outer loop to fasten the end. Films may hav

40、e possible interactions with other films that are of a diff erent generic base type (for example, nitrate versus acetate base). Cellulose-nitrate film base in considerable quantity is a fire hazard. As the film breaks down, it gives off nitric oxide, nitrogen dioxide, and other gases. Films on nitra

41、te base should never be stored in the same rolls, containers, housing, or environment with films on acetate base (see ANSVNFPA 40). Closed containers are required unless the film is protected from dirt and damage by the storage housings. Containers should be made of noncorrosive material, such as an

42、odized aluminum, stainless steel, or peroxide- and chlorine-free plastics. 4.3.3 Storage housings and rooms Motion-picture films having long-term value should be stored in closed housings or on shelves and racks enclosed by doors in a storage room. The shelves or cabinets shall be arranged to permit

43、 interior circulation of air to all film containers to provide uniform humidity and temperature conditions. The lowest shelves should be at least six inches above the floor; other precautions should be taken against potential water damage. Storage enclosures should never be placed in cardboard boxes

44、 and left on the floor Page 5 of 8 pages RP 131-2002 of storage rooms. Thestorage rooms hould be protected against f ireand associated hazards as outlined in clause document. 8 of ANSVPIMA IT9.11. The storage room should be conditioned as described in clauses 6, 7, and 8 of that I Automatic air-cond

45、itioning equipment that controls both temperature and humidity is most desirable. Slightly positive air pressure should be maintained within the storage area. Provision should be made to clean the air supply of harmful gases and to minimize dust in the room. 4.3.4 Handling techniques Prior to storag

46、e, film should be inspected, repaired if necessary, and cleaned. Wet immersion cleaning is preferred to wiping or dry cleaning. Wet cleaning may not be desirable for some specially treated films; for example, lacquered films. Preprint materials should be wound on suitable cores and prints on cores o

47、r reels, and placed inside clean noncorrosive containers, preferably one roll to a container. If a film which has been kept at a reduced temperature is removed from the storage room, ample warm-up time is necessaiy to permit the film to reach ambient room temperature before being used. 4.3.5 Duplica

48、tion and inspection When motion-picture films are duplicated, and the duplicate placed in extended-term storage, the copy should be on polyester film base. Annex A (informative) Environmental conditions Five factors are of primary importance in the storage and preservation of motion-picture films, b

49、oth black-and-white and color: container, film base, temperature, humidity, and air purity. In a properly designed film vault, solid particles, which may abrade film or react with the image, are removed by mechanical filters, preferably HEPA filters, as described in the Institute of Environmental Sciences standard for HEPA filters. Gaseous impurities such as sulfur dioxide, hydrogen sulfide, peroxides, ozone, ammonia, acidic fumes, and nitrogen oxides may cause deterioration of the base or degradation of the image in some films. The level of these compounds should be monitored and min