Properties of Light
Visual Building Blocks
Just like with scenic design, a successful lighting design is the product of the purposeful use of design elements.
In lighting design, we use what are called the "Properties of Light" which refer to a set of four (4) intrinsic, controllable properties of light that a designer can manipulate in order to create the design and tell the story.
Intensity
The most basic property of light. It is how bright or how dim a light is.
Brightness for a particular light or scene in the theatre depends on a number of factors including the number of light sources used at the time, their size, their innate brightness potential, and other factors like their color, intensity level, accessories, and the physical size of the stage and audience space.
Brightness is subjective and relative. For example, a single candle lit out of complete darkness appears brighter than going down to a single candle from a bright stage. A lot of this is because of physiology and how the pupils in our eyes adjust over time.
Our perception of brightness is also relative to the color and reflectivity of scenic pieces and costumes onstage. This is why lighting Glinda and Elphaba in the show Wicked is considered to be so difficult. Using lights of the same wattage and intensity level, Glinda will always appear brighter than Elphaba because of her un-painted skin and white costumes compared to Elphaba's green skin and black costumes.
As a result, a lighting designer must always be paying to not how bright the stage or a light is but rather how bright it appears to be.
Distribution
Refers to the form and direction of the light.
This ranges from a stark, sharp shaft of light to soft, shadowless, and diffused light. The angle of the beam and the shadow that results may be endlessly varied.
When in doubt about the type of distribution you are looking at, look at the shadows. The stronger the shadow - the more direct it is. The softer the shadow - the more diffused it is.
Color
The most instantly recognizable property of light, and also one of the easiest to manipulate when designing. Every color in the visible spectrum is available for the designer to use.
Delicate tints of color or subtle variations of white light are great for highlighting the actor's faces or to wash the whole stage in a realistic way. Deeper saturations of color or stylized color may be emphasize mood, modify or enrich the pigment of scenery and costumes, or as a special effect.
Just like in pigment, there are primary and secondary colors in light that can be mixed together to form other colors. With light, the primary colors are red, green, and blue, which correspond to the physiology of how our eyes work to perceive color. They mix together to form the secondary colors cyan, magenta, and yellow. By mixing together either all three primary colors, all three secondary colors, or a primary with its complimentary secondary color we get a version of white light.
Movement
Each of the first three properties of light can be altered or changed quickly or slowly to create movement. A room may grow darker or brighter. The light the sun will slowly change color and distribution as it goes from the bright white of day, to deep ambers and reds of sunset, to the diffused light of dusk.
Lighting designers can use movement to do things like reproduce a sunrise or sunset on stage, emphasize a dancer's movement or the end beat of a musical number, or use a follow spot to follow the principle actor during their big song. The possibilities are endless.