Before deciding to spend millions on high-end effects, stop and determine whether your visual effect can be achieved right on the stage. There are a host of tricks you can employ to add flair to your scenes without your audience even batting an eye and wondering how it was done. These include the methods of front and rear screen projection, the use of miniatures and false perspective, and even stop motion animation.

Rear Screen Projection

In the 1933 film King Kong, Robert Armstrong as Carl Denham was throwing gas bombs at King Kong on a soundstage in Hollywood. But the “gigantic” monster was in fact thirteen inches tall, filmed using stop motion animation, and added to the shot using rear screen projection. Rear screen is just what it sounds like — previously shot footage that is projected from behind onto an opaque screen with a high transmission factor. This means that it allows light to shine through to the other side. The screen is placed at the back of the scene with actors and set pieces in front.

In the case of King Kong, the monsters fought or charged from the back of the scene, but always stopped just short of the real actors. Usually a row of rocks or bushes was used to hide the base of the screen, and to help tie the projection in with the actual set. The key to good rear screen projection is matching the color balance and vanishing point with the “real world” elements. If your camera is too far to one side, the distant perspective will not match the audience's eyeline. If the color or contrast coming through the screen is incorrect, it'll look faded and fake, and the effect will be blown.

Front Screen Projection

Front screen projection is a similar gimmick to rear screen, but is much more difficult to accomplish correctly. The benefit, however, is that front screen projection can provide a sharper image for the effects footage. The best screen for this purpose is called Scotchlite and is made of glass and silver beads. It's highly reflective and produces a bright, sharp image.

With the screen placed at the back of the set, a half-silvered mirror is set in front of the camera at forty-five degrees, with the reflective side facing away from the camera. The camera should be able to see through the back of the mirror and see the set. Offstage, a projector is set in line with the forty-five degrees so that the image projected at the mirror is reflected up onto the screen. If the alignment is correct, the camera should record a seamless image of background and foreground elements. Direct lighting should be kept off the screen, since this will diminish the brightness of the image.

Shadows are the tricky part of front screen projection. When the actors and set pieces are in position, their shadows should fall directly behind them, hidden from view of the camera. If the actor moves at too much of an angle, a shadow will appear around the edges. If the projected image has too much motion or contrasting elements, it may be visible on the actor. Your shooting schedule should allow several hours for testing and rehearsal.

Onstage Miniatures

The most famous, even “classic,” use of miniatures on a set is Godzilla smashing his way through Tokyo in the 1954 version of the film. The balsa and polystyrene buildings are highly detailed, adding a great sense of realism to the destruction. But there can be smaller examples of onstage miniatures.

In his 1996 short film Father Time, director Jamie Neese included a scene where a commercial jetliner is frozen in mid-air. Actor K. C. Marsh has a great comic moment as he does a very slow take to find the giant aircraft floating directly above him. When asked how he achieved this tremendous effect with no budget, Neese explained that he mounted a toy airplane, no bigger than a foot across, directly in front and slightly above the lens. With the actor standing several feet away, they rehearsed until Marsh had the perfect eyeline, looking up as if the plane were over his head.

Stop Motion Animation

Arguably one of the most painstaking methods of filmmaking is stop motion animation. A fascinating forte, stop motion animation melds artistic skill and mechanical wizardry. The earliest version of King Kong was first sculpted in miniature on a posable armature skeleton. The animators would position the miniature in a set constructed to the same scale, and then shoot one frame of film. The miniature was then moved ever so slightly, along with any leaves, trees, airplanes, dinosaurs, or natives that were in the scene. A second frame was then shot. The miniatures were moved again for a third frame, and so forth. At twenty-four frames per second, you can imagine how long it took to create such a shot, and in 1933, this was state of the art.

Filmmakers like Ray Harryhausen and Henry Selick became masters of their own styles of stop motion. Harryhausen's army of skeletons in the 1963 film Jason and the Argonauts is still a landmark piece of filmmaking. The skeleton fight alone was shot at the rate of thirteen frames per day. In 1993, Selick revitalized stop motion almost as a genre of its own in director Tim Burton's The Nightmare Before Christmas.

The difficulty and the artistry in stop motion is the ability to time the movements into smooth, realistic action. In modern times, this has been made easier by the aid of computer-controlled robotics and camera mounts. When a miniature is photographed one frame at a time, it's not moving while the shutter is open. There's none of the blurring that occurs naturally when filming a moving object. With robotics, miniatures can be made to move just the tiniest bit, timed to the opening of the camera. The camera itself can be fixed to a movable mount, controlled by the same computer. The object and camera move at the same time, resulting in a natural-looking blur and a more realistic effect.

False Perspective

As a filmmaker, you want to utilize an audience's unconscious efforts to interpret the two-dimensional movie screen as a three-dimensional world. One simple trick to accomplish this is to take advantage of perspective. Perspective is the concept that the farther away objects are from us, the smaller and closer together they seem to be. For example, if you film a shot of a road going toward the horizon, the road appears to narrow the closer it gets to the horizon. The same goes for mountains, which in reality are thousands of feet high, but seem no bigger than our thumbnail on the big screen.

Let's say you have a small shooting space, but you want your set to appear large. One place to start is having converging lines on the floor and/ or ceiling. Since the lines obviously don't extend to the horizon or vanishing point, they'll never meet. But having them even a little bit closer together at the end farthest from the camera than they are at the near end will make the audience believe the room is bigger than it is.

The same can be done with columns, tall window frames, or vertical molding to make a room seem taller. A good example of this is the main street of Disneyland, which is lined with old-fashioned storefronts. The street level is built to normal scale, but the second and third floors of the exterior facade are each constructed at a slightly smaller scale than the one below it, giving the buildings a tall, stately appearance.

Another way to play with perspective is by having larger objects in the foreground and smaller ones in back. This may be as simple as a tall potted plant near the camera and smaller ones in the background. In Star Trek: The Motion Picture, the engineering set was made to look bigger, not only by having the floor tilt upward in the background, but also by using shorter actors in the back and taller ones closer to camera.