How Film Restoration Works by Chris Opfer from Howstuffworks
Some movies shouldn't be revisited. Johnny Depp fans and other poor, unfortunate souls who sat through "Mortdecai" will never get those 107 minutes of their lives back. The best thing they can do is embark on a Paul Revere-esque mission to warn the moviegoing masses off from the depraved beast marching through their towns from theater to theater. Sure, there are certain flicks that are so bad that some might actually get a kick out of them. Why else would so many frat bros still have "Boondock Saints" posters tacked up on their dorm room walls?
On the other end of the spectrum are films that advance the art form and tell the story of the world in which we live. These are the "Citizen Kanes," the "Casablancas," the "Godfathers" and the "Graduates" of the film industry. When aliens descend on what's left of planet Earth thousands of years from now, these are the movies that we should want them to find. That's not to mention a whole slew of flicks that are worth hanging on to because they inform us about the world, are entertaining or are just plain fun. I don't know about you, but I certainly wouldn't have realized that there's no basement in the Alamo if it wasn't for "Pee Wee's Big Adventure."
Unfortunately, many films have been left by the wayside over the passage of time. According to the U.S. Library of Congress, less than 20 percent of American feature films from the silent era remain intact. Meanwhile, half of the movies produced in the U.S. before 1950 have already been lost.
The good news is that researchers and film buffs are working to restore and preserve the movies that we still have.
Film vs. Digital
Until a couple decades ago, moving images were captured exclusively using photochemical film. You know, the stuff that comes in those big reels and that you have to hand-feed through a projector to get on the big screen. These days, however, more filmmakers are turning digital production techniques to shoot and screen their pictures. While the differences in the final product may be subtle to the untrained eye, the two techniques vary widely.
The film used to capture moving picture images has two components: A light-sensitive emulsion and a plastic base. Here's how Kodak explains it:
An easy way to think of film is to compare it with bread and butter. Think of the bread as the base, the butter as the emulsion. When you hold this combination in your hand, what you feel and see is mostly bread, the base -- not butter, the emulsion. The base (bread) holds and supports the emulsion (butter), the active part of the film.
The emulsion is a type of gelatin composed of silver halide crystals. A camera records images by transferring photons of light onto the film as it rotates behind the lens. The crystals turn into silver metal when exposed to the light and form a photo image during the film development process. The series of photos captured on the film can be seen individually once it's developed and create a moving picture when the film is run through a projector [sources: Kodak, Side by Side].
Digital recording, on the other hand, uses an electronic sensor to capture an image, rather than a chemical process. The light that travels through the camera hits the sensor's pixels, creating a number of individual electronic charges that together create an image. The images are stored as data, which can be transmitted via discs, flash drives and the like [sources: JISC Digital Media, Side by Side].
The film vs. digital debate is currently raging on just about every movie studio lot from New York to LA. Film purists often say that they like the gritty, granular feel that comes with the old-fashioned method. Academy Award-winning cinematographer Wally Pfsiter called switching from film to digital "trading oil paints for a set of crayons." Those who have embraced the technology, meanwhile, tout the immediacy of the process. Instead of shooting a scene and waiting to see what it looks like once the film is developed, directors and actors can see what they have right away. Director Robert Rodriguez has compared digital to film by calling the latter technique "painting with the lights off" [sources: JISC Digital Media, Side by Side].
Size Matters
Cinematographers typically use four different types of film – 65 mm, 35 mm, 16 mm and Super 8. The names refer to the films' "gauge," or width in millimeters. Thirty-five mm is the most commonly used type of film for movies because the size of the photos transfers most easily to the big screen. Sixteen mm is used primarily for lower-budget pictures that are later blown up to 35 mm and for TV. Images shot on 65 mm are usually printed on 70 mm film to get the widescreen feel used in IMAX movies. Cinematographers often turn to Super 8 (8 mm) for a vintage, old, home-movie feel [source: Kodak].
How Film Deteriorates
While the choice between digital film moviemaking may be one of personal preference, what we do know for sure is that film reels have a much higher risk of being damaged or destroyed over time than their video counterparts.
As the plastic and emulsions age and are exposed to elements like light and temperature, colors fade and images may denigrate. The culprit is often something called nitrate deterioration. Until the early 1950s, most American movies were recorded on cellulose nitrate film. When the nitrate deteriorates, film often shrinks and begins to give off various acids that separate the emulsion from the base, yellow the individual still photos and make the film so brittle that it eventually crumbles and turns into dust. High temperatures and humidity can speed this process. While the acetate film versions that followed are also subject to decay, modern polyester film is believed to have a shelf life of hundreds of years [sources: Library of Congress, Kodak].
It's not necessarily the Hollywood classics at risk of being destroyed because many of these films have already been restored and transferred to digital formats. Instead, it's the lesser known independent and avant-garde works, along with old newsreels, documentaries and silent era flicks that have been scattered across the country over the years. Experts say these "orphan films," which were outside the scope of previous restoration and preservation projects, are important because they provide insight into what life was like in the days they were shot and recorded [source: National Film Preservation Foundation].
Restoring Film
The actual restoration work is a treasure hunt of sorts in which film archivists go searching for the early versions of the film that they want to bring back to life. The goal is to create what's called a "pre-print" copy of the original film: a master copy of the film as it once was [sources: UCLA, The Picture Show Man].
That means first locating the cleanest copy of the film that's still available. Under ideal circumstances, that would be the original negative version. That's the film that was actually reeled through the camera and used to capture the images. It's called a negative because the original film captures the image in a backward form that includes only shades of the true colors. It's later used to create a "positive" version that ends up on the screen. You need a negative to make a positive print and a positive to make a negative print. Every duplication means a loss of quality.
For many films, there are various trial, correction and distribution copies that may be floating around and could be used for restoration. More obscure pictures – those with just one or a few copies – are often more difficult to restore because there are simply fewer versions of the film from which to choose. On the other hand, more popular films raise their own hurdles to restoration because of the wear and tear endured by the negative as a result of heavy copying.
Once the various versions of the film are located, the restorer may physically cut and paste them to create a full-length master. Wearing white gloves, he'll open the film can and gently wipe off any mold. Then he'll unwind the film slowly, flattening out any curl. Using special equipment and splicing tape or film cement, he'll join pieces of film together as needed. He'll also repair any broken sprocket holes [sources: NFPF]. The idea is to remove wear and tear so that viewers can enjoy the film in its original form rather than an enhanced version.
For a big-budget movie restoration, the film may go through a device called a wetgate scanner – a scanner that runs the film through a chemical bath that fills in any scratches on the negative. Then the film is converted to a digital image. High-end graphic and editing computers can adjust the pixels so faded color becomes rich; they can also remove damaged frames of film or scratches and dirt on individual frames. This is painstaking work. It may take three or four hours to fix one frame [source: Popular Mechanics].
The audio track may also be enhanced. In the case of the "Jaws" restoration, the mono track was upgraded to include two additional rear speakers, creating a surround sound atmosphere for home viewers [source: Popular Mechanics].
And one last thing after the restoration project is complete: Another negative is created so the film will be properly preserved for posterity.
Author's Note: How Film Restoration Works
Everything I know about film, I owe to Keanu Reeves. That's right: Mr. Whoa. Dude. Bro. Yes, Reeves has left an indelible mark on the history of cinema with roles like the stoned space cadet who travels through time to visit other civilizations and ace his history project in "Bill and Ted's Excellent Adventure," an older, jock version of the same guy in "Point Break" and an older, hacker version of the same guy in the "Matrix" trilogy. But I'm referring to "Side By Side," the 2012 documentary Reeves produced and narrated about the move away from film moviemaking and the artists on each side of the film-digital debate. This is the type of flick that humble-braggers who like movies would label for "film nerds." They are wrong: I enjoyed it, and I'm one of the coolest people whom I know.
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Sources
JISC Digital Media. "Introduction to Digital Video." (Jan. 24, 2015) http://www.jiscdigitalmedia.ac.uk/guide/introduction-to-digital-video#v08
Kodak. "Film Types and Formats." (Jan. 24, 2015) http://motion.kodak.com/motion/uploadedFiles/US_plugins_acrobat_en_motion_newsletters_filmEss_05_Film_Types_and_Formats.pdf
Kodak. "Understanding Film....The Basics." (Jan. 24, 2015) http://www.kodak.com/global/en/consumer/education/lessonPlans/lessonPlan152.shtml
Library of Congress. "Preservation Research." (Jan. 23, 2015) http://www.loc.gov/programs/national-film-preservation-board/preservation-research
Library of Congress. "Preservation Plan." (Jan. 24, 2015) http://www.loc.gov/programs/national-film-preservation-board/preservation-research/film-preservation-plan/
National Film Preservation Foundation. "Why the NFPF was Created." (Jan. 24, 2014) http://www.filmpreservation.org/about/why-the-nfpf-was-created
"Side By Side." Directed by Chris Kenneally. Company Films, 2012 (Jan. 24, 2015)
The Picture Show Man. "Restoration and Preservation." (Jan. 24, 2015) http://www.pictureshowman.com/articles_restprev_negsprints.cfm
UCLA Film & Television Archive. "About Restoration." (Jan. 24, 2015) https://www.cinema.ucla.edu/restoration/about-restoration
UCLA Film & Television Archive. "An Interview with Bob Gitt (2006)." (Jan. 24, 2015) https://www.cinema.ucla.edu/restoration/interview-bob-gitt-2006
UCLA Film & Television Archive. "UCLA Film & Television Archive on Turner Classic Movies." (Jan. 24, 2015) https://www.cinema.ucla.edu/restoration/ucla-film-television-archive-turner-classic-movies
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