ANAMORPHIC PROCESS
The technique of fitting a wide-screen image onto a standard, almost-square film frame by optically “squeezing” it. This is accomplished by photographing through a cylindrically shaped lens in addition to a spherical one. When the image is shown, it is “unsqueezed” by projecting it through the same kind of lens. When an anamorphic lens is used on a camera, the developed film image appears squeezed in the horizontal axis, making it half as wide as it should be. A circle becomes an upright oval; a square becomes a rectangle with its top and bottom half the size of its height. These distorted images are particularly difficult to deal with in the creation of optical effects, so the ILM technicians usually use a nonanamorphic camera system (VistaVision) when they composite images.
BI-PACK
Two films that run through a camera or projector at the same time, packed one on top of the other. In special effects work, one usually functions as a matte that will create an unexposed area on the film to be filled in later by some other image; the other may be the fresh, unexposed film or print to be matted. Bi-pack cameras and projectors are commonly used in optical departments and sometimes in special effects or model photography. The matte paintings for the first Star Wars film were photographed with a bi-pack camera system. Bi-pack cameras are equipped with twin sets of magazines, one for the unexposed film and the other for the matte. They run through the camera with their emulsions touching. At ILM bi-pack cameras and projectors are frequently used on optical printers and aerial image printers in the creation of elements for traveling mattes.
BLUESCREEN PROCESS
A photographic process that involves filming in front of a brightly illuminated blue screen. After optical rephotography, the process yields film of actors or objects placed against a black background, and also film of their silhouettes against a clear-white background. With these two elements—moving subjects and their identical moving silhouettes—it is possible to place the subjects into any background scene. The silhouette is used to make a moving black space in the background environment, and the image of the actors is inserted into that hole. At ILM the bluescreens are self-lit with fluorescent tubes. The subject in front is lit with white or amber light, and care is taken that no blue from the screen reflects off the subject and none of the light on the subject spills onto the bluescreen. After the film is developed it is rephotographed twice: once with a filter that turns all the blue to black and leaves the subject unaltered, and then with a filter that turns the blue to white and blocks out all other colors, so that the subject becomes the silhouette.
BLUESPILL
Bluescreen requires that an object or actor be photographed in front of a blue screen. When light from this screen illuminates the object and is seen by the camera, it’s called bluespill. Uncorrected during photography, these contaminated areas may become transparent during the optical compositing process and create an undesirable matte line wherever the blue light fell on the object. This condition usually occurs when the subject is glossy or white or placed at an undesirable angle to reflect light. Certain lenses are more susceptible to bluespill than others. An experienced bluescreen cinematographer is often able to eliminate or minimize bluespill through special lighting techniques.
FRONT PROJECTION
Also known as the Alekan-Gerard process and the Scotchlite process. A highly reflective screen is placed behind the subject being photographed. A projector is next to the camera with its optical axis at ninety degrees to the camera. A beam splitter reflects the projected image toward the screen while allowing the camera to see through; thus the camera sees the projected image on the highly reflective screen with the subject in front of it. The screen is so reflective, in fact, that only a very dim projection light is used; consequently, the foreground objects do not reflect the projected image.
GARBAGE MATTES
Animated mattes that serve to block out “garbage” in shots, such as unwanted lights, cables, C-stands, and so on. Often there are large areas of the shots in special effects elements that are not used and need to be “plugged up,” as it were, with garbage mattes. Usually they are quickly made with pieces of black paper placed above a light box and photographed with an animation camera.
OPTICAL COMPOSITE
A finished special effects shot, made up of two or more images that have been combined on an optical printer. An optical composite can be as simple as a flash of lightning in the sky or as complicated as fifty individual spaceships in a space battle. The most common optical composites place actors, photographed on a stage, into imaginary environments that combine actual live shots with matte paintings.
ROTOSCOPE
A technique in which individual frames of a movie are blown up and traced, one at a time, onto animation cels. Thus live action can be turned into animation (when the cels are rephotographed), ghostly effects can be added to live action, technical marvels can be put into real people’s hands (the lightsabers), and so on.
Rebel soldier sketch by Ralph McQuarrie.