|Cinefantastique, Volume 6, Number 1 (c)1977, pg. 43 - Land of the Lost by S.S. Wilson|
Top Right: Torchy, a flame-throwing dimetrodon and one of the new third season models, lets go with a blast. Bottom Right: The "armature monster," a slightly redressed model armature used to fill the need for a new inexpensive monster on the show. Animated to plod slowly and ponderously, it made for a rather impressive looking robot. Note electrical wiring for lighting up the eyes.
The freeze frame also allowed time for lining up "cutting pieces." These are necessary for creating the effect of an actor passing *behind* something in the background plate. Cutting pieces are blue-painted forms which are set out on the blue stage and arranged to conform to objects in the plate. So, when an actor steps behind a cutting piece whose shape matches that of a rock in the plate image, he will appear to go behind the rock because the blue form blocks his body from view and allows the background image of the rock to be inserted instead. The cutting piece, being entirely blue, remains invisible. It can also serve another purpose. If the actor walks in front of it, his shadow will pass over the rock.
Lighting is the single most critical element in getting believable composites with this system. Not only must chroma key stage lighting match the direction and contract indicated by the lighting used in photographing the background plate, it must be delicately balanced in order to pick up the subject's shadow without picking up unwanted shadows cast by cutting pieces.
Perspective is important, too, of course. The Excelsior crew provided the television crew with detailed information on camera angle, lens focal length, camera height, etc., to be applied in the proper scale to the live action shooting. In practice, the television crew found that they had some leeway in conforming to plate perspective. Gene Warren suggests that perhaps the small size of the television image made minor imperfections less noticeable than they would have been on a theatre screen.
Correct perspective is not always easy to achieve. For example, "Tag Team" found Will and Holly trapped on a ledge partway down a huge crevasse while Grumpy and Alice, above them, roared at one another from opposite sides of the fissure. The angle on the miniature set was looking up at this action, so Kathy Coleman and Wesley Eure had to be placed high on blue platforms in order to match the angle in full scale, while Spencer Milligan found himself perched even higher, to appear to be looking down at them from the lip of the crevasse.
In addition to straight composite effects, Compact Video conjured up many other electronic visual effects such as solarization, multi-colored flashes, glowing eyes, and the like. Most of these were created at Compact Video's post production facility by Bill Breshears and Jim Frazier.
How does all this video wizardry compare to film wizardry? It's better in some ways and not as good in others, depending on what you want to do. Let's consider video's advantages first.
Chroma key is similar in some respects to the filmic composite processed called traveling matte. However traveling matte requires a minimum of several days for film processing and printing before the composite can be seen, whereas a chroma key composite can be viewed immediately by simply playing back the recorded tape.