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.