USING NEW LIGHTING
TECHNOLOGY FOR
STAGE LIGHTING & LIGHT SHOWS

The new types of lamps now being sold provide both new problems and new solutions for the problems typically found in stage lighting and light shows. Here is a way to determine what kind of lamp is best for each situation to take advantages of the properties of each kind of light.

The Lamps and their Properties

* - Color temperature shifts to warm when dimmed.

Of these, halogen, metallic arc, and light emitting diode (LED) are those used in the theater most. Many devices have been created to take advantage of the properties of the various kinds of LED. These include light show devices, striplights, floodlights, and some spotlights. Many of those use RGB color mixing to simulate the colors produced by stage color media. But there are also some disadvantages to using these. These features are explored below.

Various Facts about New Technology Lighting:

1. Most new-technology lamps do not put out a continuous flat spectrum. There are peaks and gaps in their light output. See this page on new light sources for more.

   Color media can not compensate for wavelengths missing from the emitted spectrum.

2. The nonlinear output of the new technology lights can cause changes in the apparent colors produced by color media, costumes, and scene paints. See The Crayon Trials for more on how this happens.
3. Nonlinear light sources can cause eyestrain in some audience members, causing discomfort. The newer warm white and soft white fluorescents are especially likely to do this.
4. Although it is possible to make a white LED that emits evenly at all visible frequencies, no manufacturer is producing such a lamp. Environmentalists frown on such a lamp because it is less energy efficient.
5. While old fluorescent lights had standard names for the various color temperatures, the color names of the newer tubular, compact fluorescent lamp (CFL) and LED products vary by manufacturer. Use the color temperature numbers of kelvins on the package for more accurate choices.

   These are the standard names that should be used:

   Color Temp	Standard Name	Color Temp	Other Light Source	Erroneous Names Seen
   1800 K		1800 K	Candle Flame
   2100 K		2100 K	High Pressure Sodium Vapor
   2200 K		2200 K	Clear Heat Lamp
   2500 K		2500 K	40 Watt Incandescent
   2700 K	Soft White Fluorescent	2700 K	Soft White LED, 60 Watt Incandescent	Warm white
   2870 K		2870 K	100 Watt Incandescent
   2950 K	Deluxe Warm White Fluorescent	2950 K	Deluxe Warm White LED (less green)
   2960 K		2960 K	500 Watt Incandescent
   3000 K	Warm White Fluorescent	3000 K	Warm White LED	Soft White
   3200 K		3200 K	Halogen Lamp	White
   3400 K		3400 K	50-Hour Photoflood, Low Sun
   3500 K	Bright White Fluorescent	3500 K	White Fluorescent	White
   4000 K	Deluxe Cool White Fluorescent	4000 K	Deluxe Cool White LED (less green)
   4100 K	Cool White Fluorescent	4100 K	Cool White LED	Daylight
   4100 K		4100 K	Reveal Incandescent, Moonlight
   5000 K	Sunlight Fluorescent	5000 K	Sunlight LED	Daylight
   5200 K	Designer White Fluorescent	5200 K	Work Light Fluorescent (added green)	Daylight
   5900 K		5900 K	Clear Mercury Vapor (added green)
   6000 K		6000 K	The Sun
   6500 K	Daylight Fluorescent	6500 K	Daylight LED
   9325 K	Aquarium Fluorescent	9325 K	Grow Light, Northern Sky (added green)

6. One problem is that a color obtained with a CFL or LED from one manufacturer is not the same as the colors produced by products made by other manufacturers. While this is not a problem in most home lighting, it can make a large difference in theater lighting, especially if newly purchased lights don't match old ones. This becomes a problem if a product is discontinued, or if lamps are purchased by the lowest bid under government purchasing rules.

   Color media are available to make color temperature adjustments. This can often correct the problem.

7. When a color medium is used to produce a desired color, a change in color temperature of the lamp requires substituting a different color for the color medium. The color media for correcting color temperature mentioned above could help.
8. Some LED systems use RGB mixing to produce any desired color that can be mixed in this way. Among the possibilities are different color temperatures of white. RGB LED Striplights are available. But the light output necessarily has gaps in the spectrum.
9. Other LED systems have two sets of emitters that can be varied in intensity to select any color temperature from 2700 to 6500 K. But again, there are necessarily gaps in the spectrum.
10. CFLs and other fluorescent lamps cannot be used in situations where they are flashed or turned on and off frequently. They burn out very quickly if used in this manner.
11. CFLs and LEDs cause much less fading in color media than incandescent or halogen lights do.
12. Because new-technology lamps draw much less current, more of them can be powered by the existing electrical service for the building.
13. Because new-technology lamps draw much less current, more dimmers running at lower power can be powered by the existing electrical service for the building.
14. Many new-technology lamps can not be dimmed. Care must be exercised to buy the correct lamps.

Dimmers

Several kinds of dimmers exist. Each kind affects the power to the lamp in different ways:

Key:
   100% - red           75% - green           50% - violet           25% - blue            0% - gray (middle)          supply voltage (all settings) - red

Type	Current Waveform Produced	Method of Dimming	Notes
Resistive		Limiting current to the lamp	Does not work with master dimmer Load sensitive Works with DC power too
Autotransformer		Voltage divider sets lamp voltage	Insensitive to load
Reactive		Limiting current to the lamp	Somewhat load sensitive
Thyratron / Thyristor		Gating current to the lamp	Master dimmer must be in control circuits
Thyristor for CFL		Gating current, with low-pass filter	Master dimmer must be in control circuits CFL must be dimmable

LED and CFL screw-shell lamps have special power supplies built into the bases of the lamps. The capabilities of the lamp depend on the properties of the power supply. The following are typical effects experienced when various dimmers are used with different kinds of lamp power supplies:

† - The lamp draws too little current to properly load the dimmer.

♦ - Properly loading the dimmer resistively makes this lamp work.

Note that a dimmer and lamp incompatibility can damage the dimmer, the lamp, or both.

In many cases, a lamp will dim if one incandescent load remains in the circuit.

Most steady-burning LED Christmas lights have the rectifier/filter/resistor power supply. They work with a properly loaded dimmer.

Acting Area Lighting

The following items show the advantages of the newer technologies for acting area lighting:

1. One nice property about some of the new dimmable light sources is that the color temperatures of these sources remain fairly constant when the source is dimmed. This removes a problem of color temperature shift with dimming that has existed since stage lighting was first conceived.

   If the color temperature shift is desired, it can be provided by using two sets of lamps.

2. Another nice property is that many different color temperatures are available. Slight corrections with color media can produce the exact colors needed for acting area lighting.
3. Spot lighting does not need to be as accurate when the new lights are used. Some acting areas can be lit by floodlights instead of spotlights.
4. The common practice for lighting an acting area is to use two spotlights. The ideal locations for these are 45° up, as seen by the actor facing the audience, with one light on each side, 45° to the left and right of the actor facing the audience. Use the cube diagram at right.
5. The stage is usually divided into several acting areas.
6. One of the acting area lights is usually set to be brighter than the other. This light is called the key light. It provides the light that appears to the audience to be the only light source in the setting that is shining on the actor. If the actor is facing to one side, the key light is chosen to be the one that shines on the actor's face.
7. The other light for that acting area is called the fill light. It is set to be dimmer than the key, and simulates either light from another source farther away, or light that has reflected from the setting.
8. When an actor turns around and faces the other way, a process of brightening the fill and dimming the key called "reversing the key" is used. This trades the roles of the key and fill lights for that acting area.
9. More of a 3-D effect (plasticity) can be created by using different colors of light for the key and fill lights. If the key will at times be reversed, a second set of lights with the colors reversed might be needed. Lights with adjustable color temperature might also be used.
10. The choices of acting area colors for key and fill are usually made according to one of four methods. Now that we have all of these lamps with different color temperatures (and variable color temperature), there are new ways to set up acting area colors. Examples of acting-area color choices are:

    System	Warm Color	Cool Color	Notes
    Complementary Tint	2700 K Soft White	6500 K Daylight	Uses existing lamp colors
    Complementary Tint	3000 K with light pink medium	3000 K with daylight blue medium	Uses color media
    Complementary Tint	3000 K with light amber medium	3000 K with light blue lavender medium	Uses color media
    Complementary Tint	3000 K with salmon medium	3000 K with steel blue medium	Uses color media
    Near-Complementary Tint	3000 K Warm White	4100 K Cool White	Uses existing lamp colors
    Near-Complementary Tint	3000 K with salmon medium	3000 K with light blue lavender medium	Uses color media
    Related Tint	2700 K Soft White	3000 K Warm White	Uses existing lamp colors
    Related Tint	2700 K Soft White	3500 K Bright White	Uses existing lamp colors
    Related Tint	3500 K Bright White	4100 K Cool White	Uses existing lamp colors
    Related Tint	4100 K Cool White	6500 K Daylight	Uses existing lamp colors
    Related Tint	3000 K with light pink medium	3000 K with salmon medium	Uses color media
    Related Tint	3000 K with light pink medium	3000 K with no medium	Uses color medium on one side
    Single Color	3000 K with light pink medium		Dimming provides 3-D plasticity
    Single Color	3000 K with no medium		Dimming provides 3-D plasticity

    Many variations on these colors (and others) are possible.
11. More than one acting area system can be combined in the same set.
12. The choice of which set of colors to use is often determined by the mood the director wants. Warm colors can, for instance, indicate a happy mood, while cool colors could be used for (e.g.) a relaxed or a gloomy situation. Other colors (e.g. a garish yellow) can indicate tension.

Lighting the Costumes the Actors Wear

The following items show the advantages and disadvantages of the newer technologies for costume lighting:

1. The nonlinear output of the new technology lights can cause changes in the apparent colors produced by costumes. See The Crayon Trials for more on how this happens.
2. Some pigments used in costumes have unusual spectral responses that can cause drastic color changes under certain nonlinear light sources. Many pigments have sharp peaks or dips in their spectral responses that match peaks or dips in the spectral responses of nonlinear light sources, causing pronounced color shifts under these sources.
3. Some pigments fluoresce when struck by ultraviolet or blue light, causing color shifts or an unusual glow coming from the costume.
4. Costumes are made using available fabrics dyed with available dyes. The costume designer normally has no control of how the fabrics are dyed or the light under which he examines the color of the dyed fabric.
5. Sometimes costume fabrics are bought sight-unseen through internet sites, mail order, or on purchase orders put out on bids. The costume designer is thus stuck with the colors on the fabrics he receives.
6. The process used to make a color image file to display on a computer hides the effects of the lighting on the perceived colors of fabric seen in an advertisement. The fabric may appear to be an entirely different color when seen under the lights to be used.
7. The colors used in acting area lighting and the colors of costumes must be designed together. Costumes must be tested under all of the various lights that they will be seen under, to be sure that they will appear the correct color.

Lighting the Scenery and Setting

The following items show the advantages and disadvantages of the newer technologies for scenery lighting:

1. It is the usual case that the acting area lights will also cause light to fall on the setting. If this is not enough light, or if it is the wrong color, extra lighting can be added to adjust the amount or the color of the light.
2. Often the only extra lighting needed is a light of a selected color temperature sufficient to offset the color temperature of the acting area light falling on the setting.
3. Two lamps at opposite ends of the color temperature scale can adjust for any final color temperature.
4. Other arrangements could include an RGB set of lights, or a combination of RGB and white.
5. If footlights are used, make sure they do not shine enough on the setting to cast shadows of the actors on it.
6. Some pigments fluoresce when struck by ultraviolet or blue light, causing a color shift or an unusual glow coming from the setting.
7. The nonlinear output of the new technology lights can cause changes in the apparent colors produced by scene paints. See The Crayon Trials for more on how this happens.
8. Some pigments used in scene paints have unusual spectral responses that can cause drastic color changes under certain nonlinear light sources. Many pigments have sharp peaks or dips in their spectral responses that match peaks or dips in the spectral responses of nonlinear light sources, causing pronounced color shifts under these sources.
9. Using mixtures of magenta, yellow, and cyan transparent paints with a white base will make the setting paints look the same under more variations in the kind of light used.

Lighting a Cyclorama or Sky Backdrop

The following items show the advantages and disadvantages of the newer technologies for sky lighting:

1. RGB LED striplight systems are ideal here. Other RGB systems would be equally effective.
2. The ideal system would have one set of instruments at the top of the sky drop or cyclorama, and another set of instruments at the bottom. This can make some very interesting sky effects, especially sunrises and sunsets.
3. One or more Linnebach projectors with cloud cutouts can add clouds to the sky image. Inverse cloud cutouts might be needed for sunset and sunrise effects. A nearly concentrated RGB source is useful here.
4. A Linnebach projector with holes punched in the mask can provide the moon and/or stars. Use a cool-colored white source.
5. Do not attempt to directly show the sun. Instead, use a spotlight to simulate a sunbeam.
6. Don't overdo the sky effects, or they will distract people from the action and dialogue on the stage.
7. Some pigments fluoresce when struck by ultraviolet or blue light, causing a color shift or an unusual glow coming from the cyclorama. Make sure the cyclorama is not made of or colored with fluorescent materials unless a special effect is needed.

Special Lighting Effects

The following items show the advantages of new technologies for special lighting effects:

1. Lightning effects can be simulated best with photographic xenon strobe lights set for single flash operation and triggered remotely, sometimes multiple times.
2. Fire effects are created with rapidly flickering lights, rotating drums covered with foil, and/or fan blown strips of tissue paper. Use of constantly varying colored lights (red, orange, yellow) on these other devices makes the effect more real.
3. If a fireplace is desired, one of the many fake fireplaces on the market can be used. Turn off the heater function.
4. A fire off stage can be simulated by the use of constantly, but slightly varying colored lights (red, orange, yellow) shining on one side of the cyclorama.
5. Explosion effects can be created with a sound effect, a colored flash of light, and/or a spring device hurling harmless fake debris into the air.

Special Sound Effects

The following items show the advantages of new technologies for sound effects:

1. Surround sound effects can place sounds anywhere you want them in the theater. Use the techniques found here to record them. Use a Dolby Surround system to play them into the theater.
2. Use two or more recordings of thunder mixed together at different pan positions to create very realistic thunder.
3. The voices of ghosts can be panned into the surround areas of a Dolby Surround system for a unique effect. Use lots of reverb, panned near, but not on the sound.
4. The Surround field microphone can be used to record any real outdoor event. Play it back through Dolby Surround.

Lighting a Musical Performance

The following items show the advantages of the newer technologies for lighting musical groups:

1. Since plasticity is not as important in a musical performance as it is in stage use, the tricks needed for acting area lighting are not as necessary. But if acting-area lighting is already in place for another function, and it covers all of the performers, it can be effectively used.
2. The main need for an orchestra or a band is plenty of glare-free light in the following places:
   • Light provided for the audience to see the performers
   • Light provided so the performers can read their music
   • Light on the conductor (if any) and his music

Light Show Techniques - New and Old

The following items show the advantages of the newer technologies for light shows:

1. New striplights can be flashed rapidly to provide a strobe effect.
2. Single lamps or striplights can be sequentially flashed to make a rotating effect.
3. Many special effect devices based on LASERs or LEDs are available.

The following items show some of the older tricks for light shows:

1. One colorful effect is to place powerful red, blue, and green floodlights (placed in that order) in footlight position several feet in front of a band. The light beams overlap to light the band members with essentially white light, while the shadows they cast on a white cyclorama are brilliantly colored.
2. Staple a piece of reflective Mylar or reflective diffraction grating Mylar to a wheel and rotate it with a slowly rotating motor. Aim a slide projector at it and aim the reflection at the band.
3. For special effects from a powerful overhead projector, make a cover for the objective lens using 120° segments of red, green, and blue color media. This causes any deflection of the projector beam to be colored. Then use it for any of the following:
   • Make a colorful wet show with clear water. Put about 3/8 inch of clear water in a clear Pyrex pie pan, and place it on the projector stage. Then use any of the following techniques to produce a colorful display:
     1. Drip clear water into the pie plate from a dropper bottle. The drops create expanding colored rings.
     2. Squirt clear water into the pie plate from the side.
     3. Oscillate the pie plate so the water sloshes back and forth in different directions. This changes the color of the beam.
     4. Attach a wand to the cone of a small speaker fed from the band, and dip the end of the wand in the water.
     5. Use a stick to stir or ripple the water.
     6. Drop an effervescent antacid tablet into the water and watch the action.
   • Make a waterless "wet show" using the following techniques:
     1. Use various clear plastic containers and objects in the projector beams. Move and rotate them around above the projector stage. Tilt them to make different colors.
     2. Get two of those corrugated clear plastic trays fruits are sold in. Hold them one above the other above the projector stage, and wiggle them around.
     3. Hold one or two pieces of clear rippled light fixture ceiling panel in the beam and move them around. Different patterns in the plastic make different effects.
4. An ultraviolet light source combined with black costumes and a backdrop colored with fluorescent pigments can produce interesting shadow effects.