Functions and Qualitites of Light
Theatrical Design Logo
Functions & Qualitites of Light

Functions & Qualitites of Light

Single web page.

Func-tion \'fen(k)-shen\ noun the action for which a person or thing is specially fitted or used of for which a thing exists.

Qual-ity \'kwal-et-e\ noun peculiar and essential character: an inherent feature.

The functions of light and the properties that affect them.

There is an old adage that states that lighting designers should “light the play, not just the stage.” Considering the functions of the lighting designer for each specific production can help you focus down on your objectives; what does the lighting want to accomplish?

The functions of stage lighting are the objectives or purposes for which the designer influences and controls the qualities of light we are about to investigate.

Stanley McCandless (1897-1967, considered the “father of modern lighting design”) assigned four functions for stage lighting: visibility, naturalism, composition, and mood. Modern writers typically substitute modeling or form revelation for naturalism. I also like to add establishing given circumstances this mix.

Lighting designers are often employed to work on dances, corporate theater (award shows, product roll-outs like Apple iPhones), and nontraditional works… So let’s modify that old adage to reflect more of what we do; “light the production, not just the stage.”


The ability for the audience to see the performer, or product, is under the control of the lighting designer. To show the performer in different ways is the primary responsibility of the lighting designer.

The single, most important function of stage lighting is to supply visibility – enough light to see the actors and setting.

At times, the audience cannot see the performers well or may not be able to hear them because the audience cannot see the actors' mouths move. This reason partly explains why some people speak more loudly into phones than during regular face-to-face conversations.

Seminar production photo
Seminar production photo. Lighting design & photo by Kade Mendelowitz.

The single, most important function of stage lighting is to supply visibility – enough light to see the actors and setting.
Dead Man's Cell Phone production photo
Dead Man's Cell Phone production photo. Lighting design & photo by Kade Mendelowitz.
Sometimes you want to shroud the character in mystery by hiding their mouths - but do so selectively.

Focus & Composition

Selective focus, directing the audience’s attention, is another key function of the lighting designer. We are often called upon to ensure the audience is paying attention to one actor or area.

You may want to direct the audience’s attention away from a set change, to highlight a particular actor, or to make sure the audience sees a particular action.

It is often said that the most powerful acting is reacting. It can be stronger to help focus the attention of the audience away from the character who is speaking (or doing) and onto the character who is learning (or seeing) the new information or action.

If a character pulls a knife out of a drawer and hides it behind his back for the rest of the scene, no tension will be created if the audience doesn't see the character take the knife.

The overall visual design is called composition. None of the other visual elements works without light. They will not be seen. While the lighting designer does not have absolute control over all the compositional elements on stage, both light and shadow add visual interest and texture as well as focus to the overall picture.

Oedipus Rex production photo
Oedipus Rex production photo. Lighting design & photo by Kade Mendelowitz.
Is there any question as to where the audience should be focusing their attention?


Plasticity, or modeling, shows the 3-dimensional nature of an object or person. A set with true brick texture will not be understood without the proper lighting to emphasize the shape of the set.
Singin' in the Rain bts Singin' in the Rain during production
The "Rain Wagon" from"Singin' in the Rain" had texture built-in so the water didn't run flat. Lighitng helped emphasize the effect. Behind-the-scenes and production photo by designer Kade Mendelowitz.

Actors, too, may look more or less 3-D depending on how they’re lit.

Amanda flatening lighting. Amanda dimensional lighting.
Amanda - model photo.
An example of why driver's license photos aren't flattering / "doesn't look like me": the flash lighting shows details, but fills in shadows people are used to seeing (under the nose, etc).


Sometimes the most important feature of lighting is how it can affect the mood of the play. Who else but the lighting designer can make the pub appear smoky, the living room, romantic, or the office, sterile.
Hamlet Dreams
"Hamlet Dreams"production photo by designer Kade Mendelowitz.

Given Circumstances

Circumstances include considerations such as time of day, season, location, suggested lighting sources, and historical period. Although scenic and/or costume design has the tools to more specifically establish the reality of a setting, light can greatly add credibility to the stage illusion.

The functions of light represent the goals the designer hopes to achieve with light. All the functions are related, and whatever you do with the lighting will reflect your choices among these functions. In addition to these functions of light, there are also four qualities of light which can be controlled to also achieve your goal.

Speech and Debate production photo
Speech and Debate production photo
"Speech and Debate" production photos by designer Kade Mendelowitz

Qualitites of Light

You may decide for a particular scene that visibility is the driving force behind your decisions – perhaps there is a lot of physical comedy that needs to be seen clearly in order to be appreciated by the audience. Later, you may want to emphasize the mood of a scene. The qualities of light will help you achieve whatever your goals may be. The qualities are what you control to get the effect you desire.


Distribution includes how even the light is across the stage and the type of light seen.
Is it smooth or textured?
Does the light fade off or are there shutter cuts?

Distribution may help focus the attention of the audience to a particular area or may reinforce the set by showing the lighting change between different areas on stage.
How I Learned to Drive production photo
"How I Learned to Drive " production photo by designer Kade Mendelowitz


Intensity is the relative brightness onstage. If a scene should appear to be lit by candle-light, a theatrical lighting designer usually cannot use just one candle as the light source – it would not be bright enough for an audience an average of 20 feet away to see the performer.

If the actors are describing a bright, sunny day in the middle of June in a field, it would look odd if the lighting did not reinforce this idea.

Placeholder image
"A Christmas Carol" production photo by designer Kade Mendelowitz


There are three types of movement the lighting designer may manipulate for a production.
I will always remember watching a production of “Red Noses” in graduate school. I was master electrician, and, at one point, nearly a dozen actors walked across the stage, illuminating their own way holding lanterns I had rigged up. It was a beautifully theatrical moment.
Physical movement of light onstage, such as when an actor carries a flashlight or lantern across stage.
View the video directly on Vimeo or YouTube.
The second is physical movement of the seen light, as in the use of a follow spot or vari-lights at a music concert.

View the video directly on Vimeo or YouTube.
The final type of movement is cueing, the change from one look to another.
Of importance is whether the change is a “bump” (zero time), fast, or slow. Is the sunset fast and unnatural, or does the light on stage slowly fade?


Light can be any color of the spectrum you can imagine. Each color affects perception as well as the color of the object it hits.

Color is explored in depth in a later section.
Help! Help! The Globolinks production photo
"Help! Help! The Globolinks" production photo by designer Kade Mendelowitz