Nitrate Film - A Major Problem in Movie Restoration
(Watch a documentary about film preservation at the end of this article.)
In 1887, the Reverend Hannibal Goodwin (1822-1900) applied for a patent on a method of preparing a celluloid support for photographic emulsions that was titled, "Photographic Pellicle and Method for Producing Same". Photography had been his hobby, and in the search for a better material than glass to use for his lantern slides, he experimented with the recently discovered material, cellulose nitrate. Although the material was originally too inflexible for his purposes, he discovered that by adding fusel and banana oils he could improve the formula. By the time his patent was granted in September, 1898, George Eastman had already started production of cellulose nitrate roll-film using a similar process developed by his employee, Henry Reichenbach. Each process produced the same clear, flexible base that was ideal for film strips. (Goodwin eventually sold his patent to Ansco, and Ansco successfully sued Eastman Kodak for infringement of the patent and, after lengthy litigation, was awarded $5 million.)
However, the Eastman Kodak Company quickly cornered the market to manufacture and supply raw film stock to the motion picture producers in the United States, and from the earliest days of the cinema virtually all commercial 35mm films were made using their "nitrate film stock" (as it was called). This nitrate stock continued to be used for motion picture production until the early 1950s when motion picture production companies switched to a presumably more chemically stable and fire resistant cellulose triacetate film, which was called acetate "safety" film. (By the 1990s, however, when acetate safety film also proved to be chemically unstable, it had been replaced as the "industry standard" by polyester film that was thinner, stronger, more flexible and more transparent than either acetate or nitrate film, and hopefully more stable.)
Nitrate film produced a wide tonal range, and was valued for the rich luminous, high-contrast black and white quality of the resulting image. It is said that nitrate film produces a "shimmering visual beauty" lost in even the best new copies. Under the right conditions, it can also have a long useful life, as demonstrated by such surviving examples as the original negative for the 1903 movie "The Great Train Robbery". However, it is also a very dangerous material.
When new, nitrate film can be ignited with the heat of a cigarette. Partially decomposed, it can ignite spontaneously at temperatures as low as 120°F (49°C). Nitrate film burns rapidly, fuelled by its own oxygen, and releases toxic fumes. A 1909 fire at the Ferguson Film Exchange Building in Pittsburg prompted the National Board of Fire Underwriters to draw up regulations regarding the handling and storage of nitrate films. When early experiments produced a noninflammable film stock, it was not widely used for commercial movies because the safer film was prone to shrinkage and curling, and it quickly became dry and brittle causing splices to part and perforations to break.
As nitrate film decomposes, it goes through a number of stages:
- Amber discoloration with fading of picture.
- The emulsion becomes adhesive and films stick together; the film becomes brittle.
- The film contains gas bubbles and gives off a noxious odor.
- The film is soft, welded to adjacent film and frequently covered with a yellowish, viscous froth.
- The film mass degenerates into a brownish, acrid powder.
Partially because of this chemical instability, it is estimated that less than 20% of films made between 1890 and 1930 survive; and of the 21,000 feature-length films produced in the U.S. before 1951, only about half have survived.
As time and the ravages of chemical deterioration continue to take their toll, salvaging, restoring and preserving early films is becoming increasingly more important for both historical reasons and, as the studios are discovering, also for monetary reasons. The emergence of a consumer market, that has proven eager to acquire videos and DVD's of early movies, has created a major new outlet for the owners of film libraries.
To date Ted Turner has spent over $40 million restoring and archiving his acquisitions from the MGM/UA film library. In 1990, Paramount opened a new $11 million archives building, with low-humidity cold vaults for preprint and color materials, and during the following years spent over $35 million inspecting its negatives, audio tracks and color separations, doing film repair and printing new preservation materials. Sony has set up the Sony Preservation Committee to discuss issues related to preservation and to enter into joint restoration projects. It has become clear that a movie studio's film library is a key corporate asset. (It's interesting to note that a company called Lowry Digital has been hired by MGM to make digital masters of nine James Bond films. The equipment used by Lowry Digital creates a digital replica of each frame that consists of 4,000 horizontal lines of data. By contrast, high-definition televisions reproduce only 1,080 lines of data.)
However, the problems related to saving these early movies remain immense. Since no type of film stock has proven to be completely acceptable for long term archival preservation, and since the digital preservation of films has produced as many concerns as solutions (costs are high, the bits and bytes are vulnerable to the corruption of "digital decay", and the software and hardware to play them becomes quickly obsolete), the final answer has yet to be found.
The following products will help you explore this subject further:
DVDs: (excellent examples of films restored from their original nitrate negatives)
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