Light Source: Sound and Light Shows

Does your story need a police cruiser, a speeding train and a space ship? How about a nice little nuclear blast? With lighting, you can create spectacular elements with little or no budget. How? By keeping the expensive or impossible stuff off-screen and helping the audience imagine it. (That’s why sound is so important to the illusion that we’ve given it space in our title.) The key to the whole process is a corollary of the first great law of the video universe:

If you imply that something outside the frame exists, then it does exist.

The Basics of Lighting Effects

Whether you’re faking a cheery fire or an atomic fireball, there are three keys to creating off-screen lighting effects:

  • Match color, angle and brightness.
  • Support the effect with audio.
  • Use editing to sell the gag.

    To illustrate these concepts, let’s examine the flashing red light of a police cruiser. The problem you face is that you need to show an actress reacting to an actual auto accident that was taped several nights earlier. To do this, you need to see regular flashes of red on her face – flashes presumably produced by the rotating lights on a police car.

    Your key light should be gelled to match the amber tint of the street lights at the accident scene. Now for the red rotating light: Obtain a standalone flasher that you can plug into an outlet, run off batteries or power with a 12 volt cigarette outlet and position it off-camera. To implement the three basic principles:

    Match color, angle and brightness. If your flasher isn’t red, wrap a red gel around it, to match the color of the light on the police car. To approximate the height of the original, position the fake light at police car roof level. To adjust the brightness, watch a reference monitor as the assistant moves the light closer to your reporter. If the light is so feeble (as it might be for a battery-powered light) that it has to be very close, you’ll need to choke up to a very tight close up.

    Support the effect with audio. If you did your job properly at the original accident, you’ll have recorded footage with plenty of ambient sound (police radios, passing traffic, off-camera talking) to use as background. Laid under the shots of the onlooker, the real location sound will tie her shots to the actual accident footage.

    Use editing to sell the gag. Special effects always work best if you prepare the audience for them. So, instead of starting with the observer, show the accident, culminating in a shot that includes a prominent rotating red light. Then cut to the woman in the window. After starting her speech on camera, cut away frequently while continuing her voice over the real accident footage. Unless your visual match is extremely good, give less time to reporter closeups and more to the accident.

    Subject Lit by a Video Screen

    In a submarine, a space ship or a mad scientist’s lab, subjects often seem to be lit by the scopes or data screens they’re peering at. Some of these screens show data, while others show changing graphic or video images. These screens present two problems.

  • Their actual glow is often too weak to reflect properly on the faces of the actors watching them.
  • Their images or data are supposed to change constantly, but the on-set prop monitor displays don’t.

    The trick is to simulate their glow with an external light. To start, place a lamp out-of-frame at display screen height (on the camera side of the frame) and aim it at the subject’s face. Use barndoors to mask light spilling onto areas that would give away your fake light source. Since the light will be filtered for color, white balance isn’t critical, so you can adjust intensity with a small dimmer. Dimming a tungsten or halogen lamp warms up its light color. In general, light dimmers are invaluable in creating special effects where slight color shifts aren’t important. For some applications, you can use a dimmer to purposely warm up a light to simulate candlelight or a sunset through a window.

    For data screens, use a light blue or green gel as appropriate. To simulate the effect of changing data, wave paper strips (or even waggle fingers) in the light to create shifting shadow patterns. Stay close to the light source, to keep these shadows very soft. For video displays, you’ll need several different hand-held colored gels. Since each video scene has a basic overall tone, color shifts are most obvious at scene changes. So, for example:

    CAPTAIN RICARD

    Show me the Zorg ship, Lieutenant.

    CUT TO:

    Close on the lieutenant as she rapidly keys instructions at her monitor screen. The color wash on her face abruptly shifts from neutral to bright purple as an off-camera lighting assistant whips a purple gel in front of her screen light.

    To sell this gag, the editor will do two things:

  • Lay in the YUM-YUM-YUM-YUM throb of the dreaded Zorg ship (even though there’s no sound in the vacuum of space).
  • Cut to a shot of an actual screen showing a graphic of the bright purple ship.

    When they fill your frame, screen displays deliver ample light for a quality image. The tough part is lighting the screen bezel (surrounding plastic) without degrading the light from the screen – but that’s another topic. When a proton cannon blast from The USS Entrepreneur blows up the enemy, whip the gel away from the spotlight, and Quickly run the dimmer up to full (keep your camera’s exposure control on manual to avoid compensating for the change).

    The sudden overexposure on the watching lieutenant’s face will convincingly simulate a humongous fireball and you won’t have to animate the explosion in your computer-based graphic of the Zorg ship.

    Environmental Lighting

    Sometimes, you want an entire scene lit by an off-screen source like a fire. As usual, match color, angle and brightness with a low lamp and an orange gel, placed far enough away to deliver the right intensity. I prefer a fairly small floodlight instead of a spot: its light is fairly directional, but it throws soft shadows.

    To get the right flickering look, cut a sheet of newspaper part-way into strips, as if making a hula skirt, and tack the uncut edge to a stick. By gently waving the paper streamers in front of the light (or blowing them with a fan), you can get slow-moving fire shadows on the actors’ faces. Audio support for this effect is obviously ambient fire crackling.

    To sell the gag, intercut shots of an actual fire (that may have been pre-taped at a different location entirely) with angles on your apres-ski romantic scene. You can enhance the illusion by using a blue-gelled rim light to model the actors’ hair and shoulders, as if moonlight were coming through a window behind them.

    For a scene in a photo darkroom, you’ll need a different technique. Be sure to show the dim red bulb on-screen that is supposedly supplying all the light. Then, red-gel a spot inside a very large source like a soft box or at least an umbrella. That will cast a very diffused red glow over the scene.

    Here’s an alternative: If the actual red bulb is above the work sink and you’re shooting the technician in profile messing with developer and fix, place a big white card out of frame behind the sink and use a high spot to bounce red light off of it onto the subject.

    The situations we’ve covered are just a few examples of the endless effects you can create with off-screen lights, but the techniques are quite similar for all of them. Above all, remember that the editor should reinforce the illusion with audio and sell the gag by intercutting the specially lit material with the real-world light source. And as you light the scene, take special care to match the light’s color, angle and brightness. Finally, always have a good reference monitor (not just the tiny LCD view screen on your camcorder) to check your effect.

    Good shooting!

  • LEAVE A REPLY

    Please enter your comment!
    Please enter your name here