Light Designer's Goals
Lighting design is a more subtle element of a theatre production than those you have encountered thus far.  Until you specifically look for shifts in light or how the light is effecting your perception of a scene, you might not have any conscious awareness of the lighting.  The goals of the lighting designer can be divided into five major categories.

1.  Selective visibility:  the lighting designer makes the stage visible to the audience;  he also selects what should be seen and what should not be seen at any point in the play.

2.  Establish time and place:  although lights are more subtle than the scenery and costumes in giving the location of the play, lights can also provide important information such as time of day, season of the year, or places like a city, desert, or forest.

3.  Influence mood:  lights are an important tool for creating the mood of a production.  Simply shifting the color or intensity of the lights will change the emotional quality of a scene. Consider how you feel on a dark, gray day in March versus a bright, sunny day in July. Consider how sunsets or moonlight effect your mood. Look at the two examples of the same set with two different light cues.

4.  Reinforce style:  lighting designers can either create an illusionistic effect by simulating real light sources like the sun or chandeliers -- called motivational lighting -- or a highly stylized effect by lighting the stage in a way that could not possibly come from "real" sources.

5.  Visual rhythm or movement:  the lighting designer is important in establishing the rhythm of a production:  he determines how lights change from scene to scene, within scenes, and into intermission and the end of the play. Use of lights will encourage or discourage applause at the end of musical numbers, scenes, or acts, for example.

Light Designer's Tools
Like the other designers, a lighting designer has both artistic and practical tools.  However, the properties of light are distinctly different from the elements of design used by scene designers and costumers.

Artistic properties of light:
1.  Intensity means how much light is given off by a single lighting instrument.  This is determined both by the wattage of the bulb and the setting of a dimmer, which works much like a dimmer switch you might have at home.

2.  Color of the light is determined by a piece of gelatin, or gel, placed in a metal frame and attached in front of the lens of the lighting instrument.  Lighting designers always use colored gel because a bare instrument gives off very harsh light that will wash out details of stage objects, including actors' faces.

3.  Direction or angle of light means where the light is placed in relation to the stage action.  To preserve the 3 dimensional effect of stage objects, which appear 3D to us largely because of ambient light, several lighting instruments are used.  The key light is the major source or light while 2 or more fill lights are placed at different angles to light stage objects and actors from all sides.  Lights can be placed to any side of the stage and are named according to their relationship to the stage: top light, back light, side light, or front light, for example.

4.  The distribution or shape of light refers to where on the stage the light falls.  Some types of lighting instruments give off a more diffuse light, whereas other instruments have a beam that can be focused and/or shaped with shutters built into the barrel, helping the designer with selective visibility.  Another way to shape the light beam is by placing a metal cutout in front of the light;  these cutouts are called gobos or patterns.  They might be used to project foliage or cloud patterns, for example.

5.  The movement of light is created by shifts of light over time.  Lights rarely remain static for an entire scene, instead they are likely to shift subtlely as the mood of the play changes or as the actors move from one area of the stage to another.  Dimmersare used to control the movement of light.  Designers almost always want lights to fade in or fade out or cross fade;  the last of which means to move slowly from one set of lights on at a certain intensity to a different set at a different intensity.

Light Designer's Practical Tools
The light designer's practical tools include the various kinds of lighting instruments, gels, gobos, cables, dimmer boards, and a knowledge of the circuits in the theatre and electricity generally.

Most important are the lighting instruments themselves, which fall into three basic types:  spotlights, floodlights, and strip- lights.

1.  There are several types of spotlights, all of which share the cone shaped beam that defines a spotlight, but each of whgich has different capabilities.  Most familiar are follow spots, which are operated manually and throw an intense, focused beam of light and are usually used to "follow" an actor or singer.  An ellipsoidal spotlight is also an intense light that can be focused tightly;  unlike the follow spot, its beam may be shaped and it is usually static.  The fresnel is the least sharply focused of the spotlights and has little ability for adjustment;  its lamp slides within the barrel to adjust the hot spot in the center of the beam.

2.  Floodlights throw light over a broad area and can not be focused.  They may be used to light a background or large stage areas.  Lamps may be as bright as 2000 watts.  The most typical floodlight used on stage is the scoop.

3.  Striplights are typically used either as footlights or to throw lights across a drop or cyclorama.  Typically striplights come in 6 foot sections, each containing 12 lights that may be operated together or independently.  They are used to send strips of light comparatively short distances.  Often they are gelled in multiple colors.