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].