Radiation imagery chemistry: process – composition – or product th – Color imaging process – Color correcting
Reexamination Certificate
2001-11-26
2003-03-25
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Color imaging process
Color correcting
C430S361000
Reexamination Certificate
active
06537737
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a method and apparatus for restoring and enhancing film. More particularly, the invention concerns a method and apparatus for the restoration and enhancement of faded color or reduced contrast black and white motion picture films.
2. Discussion of the Prior Art
Motion pictures have come to represent an important part of our cultural heritage, and like some other art forms, their restoration and preservation presents substantial challenges to the archivist. One of the most serious problems inherent in color motion picture films is dye fading. Particularly devastating is the color fading of films produced by the Eastman Color process. The well-known Eastman Color process was introduced in the early 1950s and ultimately supplanted the black and white films as well as the dye transfer Technicolor films that were the principal film systems in use during this period. The Eastman Color film, starting at mid-century, eventually became the principal system for producing the motion pictures that were exhibited in theaters around the world up to the present day.
By the 1960s, it became apparent that the dyes of the Eastman Color films, both positive and negative were inherently unstable. With the passage of time, positive prints typically faded to a pallid red, with some very washed-out yellow, and virtually no blue. This undesirable fading characteristic was especially true of films that were stored at room temperature or above.
In the early 1980s, the Eastman Kodak Company reformulated Eastman Color to provide improved color stability, but there remained several decades of film making suffering from varying degrees of color fading.
The usual way the color film fading problem is dealt with by film laboratories is to produce new prints from faded negatives by using filters that add yellow to these prints and that restore, to some extent, natural skin tones. However, this technique is less than completely satisfactory and the viewer of the reprinted film experiences the motion picture through a yellow haze.
With regard to black and white motion picture films, which include many of the great films of the past, a problem often encountered is a limited contrast range. Films intended to have a rich range of contrast, including jet-blacks, exhibit only an assortment of pallid grays. This can occur in either positive or negative films. This undesirable reduced contrast range can be attributed to a number of factors.
Until about 1950, theatrical motion pictures were photographed on highly flammable, chemically unstable nitrate film stock. Much of this film has turned to dust, or been lost in fires. This, coupled with the need to protect the important nitrate elements that remain, has resulted in the films of the past typically being printed several generations away from the camera negative. Black and white films made after 1950 on safety stock are also typically printed generations away from the original negative, as these original elements could sustain damage if subjected to repeated use.
As a general rule, in copying motion pictures or photographs, contrast is reduced to preserve gradations of tone. While special film stocks used in copying are designed to preserve the quality of the original photography as much as possible, there are inevitably significant losses, and a wide contrast range is often sacrificed in order to retain subtle gradations. Not only is the picture area affected by this compromise, but also the optical sound tracks of black and white films, which can suffer from under exposure in printing and development. This can result in distortion and excess noise being heard on playback. If the films are to be exhibited through electronic means, on cable television, DVDs or the like, these problems can be lessened to some extent by digital or other electronic processing, but this is generally considerably less desirable than making improvements in the original track itself.
In dealing with the various problems of motion picture color, contrast, and sound, the prior art has failed to disclose or remotely suggest the novel processes of the present invention, and, therefore, is generally irrelevant. For example, U.S. Pat. No. 4,717,646 that relates to the restoration or color correcting of color photographs by the hand application of colors is of little pertinence to the present invention since it discloses techniques that are not applicable to motion pictures.
U.S. Pat. No. 5,796,874 that relates to the restoration of faded images by means of conforming the faded image to a restoration model using a computer program similarly lacks pertinence since it teaches a completely different approach to the solution of the problem of film restoration.
U.S. Pat. No. 3,643,569 that involves color restoration by filters rather than improvement of the films themselves, is also generally irrelevant, and discloses a process different from that of the present invention.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method and apparatus for restoring and enhancing motion picture films.
Another object of the invention is to provide a method and apparatus of the aforementioned character that will restore and enhance both color and black and white motion picture films.
Another object of the invention is to provide a method as described in the preceding paragraphs in which the motion picture film is controllably exposed to vapors emitted from a heated chemical solution, but is not, at any time, immersed into the chemical solution.
Another object of the invention is to provide a method for enhancing the optical soundtracks on black and white motion picture films.
A particular object of the invention is to provide a method and apparatus for restoring the color balance of faded Eastman Color motion picture films manufactured by the Eastman Kodak Company; as well as films employing the same essential technology manufactured by others.
By way of summary, the present invention comprises a process through which, by chemical treatment and exposure to light, Eastman Color motion picture films, both negative and positive, of any vintage, can be restored to their original color values, and, additionally, black and white motion picture films, both negative and positive, of any vintage, can be enhanced by an expansion of their contrast range. The identical process is used in enhancing both color and black and white films. Enhancement of black and white film in accordance with one form of the invention includes an expansion of the contrast range of the film, turning murky grays into deep blacks, bringing out textures in set and costume design, and revealing artistic lighting effects that were either muted or lost. Optical soundtracks on black and white films are also improved by the method of the invention. In this regard, under exposed or under developed soundtracks are brought to a state of higher definition. Variable area soundtracks are sharpened in focus, and heightened in contrast, resulting in a track of lower distortion and higher signal to noise ratio. Additionally, variable density tracks are enhanced to reveal all the subtleties of their tonal gradations, with better defining of where those gradations begin and end. This results in lower distortion, greater clarity, and more naturalness when the soundtrack is reproduced.
REFERENCES:
Abstract of JP63119385A, May 1988.
Brunton, Esq J. E.
Le Hoa Van
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