Monday 21 November 2011

Event Lighting Design: Part Two

Color 

As with the design tools of event décor, color is the most noticeable and strongest quality of light. Indeed, all light is colored, and white light is simply a mixture of all visible wavelengths (colors) between infrared and ultraviolet radiation on the electromagnetic spectrum. One of the keys to good lighting design is a thorough understanding of color. We begin with some definitions.


Hue is the pure form of a color with no white, black, or grey added. Tint is the mixture of a hue with white. Shade is the mixture of a hue with black. Tone is the mixture of a hue with black and white (grey). It is sometimes also called value. Saturation refers to the amount of hue in a color mixture. For example, a pure red color (like fire-engine red) would be said to have a high saturation of red. Figure 1 below illustrates these relationships in a triangular form.


Figure 1: Tints, Tones, and Shades (Courtesy Gillette, 2000 - Redrawn by author) 

In the world of lighting, the color wheel takes on a slightly different appearance from the color wheel associated with décor (which uses pigments). For light, the primary colors are red, blue, and green. The secondary colors are yellow (mixture of red and green), cyan (mixture of green and blue), and magenta (mixture of red and blue). Figure 2 illustrates a lighting color wheel (also called a visual or RGB color wheel).


Figure 2: Lighting Color Wheel

The two differing color wheels, the one for pigment and the one for light, are often confusing since they do not make logical sense when mixing colors. Technically, as pointed out by Fitt and Thornley (2002), “the lessons learned from mixing the colors of paint are somewhat different to those for mixing the colors of light. It has to be realized that light is the source of all color, but pigments in paint (or in dyed fabrics – author) are simply reflections or absorbers of parts of the light that illuminates them If a beam of red light and a beam of green light are superimposed the result is yellow. On the other hand, if we mix red and green paint, we get rather a nasty looking ‘brown black’ color. When using light, all spectral colors can be created by adding various component parts of red, green, and blue light and the system used is called ‘addition,’ ultimately creating white. Pigments derive their colors by subtracting parts of the spectrum, therefore the system with pigments is called ‘subtraction’ and ultimately creates black.” 

For special events, the LD is frequently called upon to not only light stage performances, but also decorative elements. These are particularly sensitive to the interaction between the hues of light and pigment hues, since most décor is pigment-based (e.g. fabrics, painted surfaces, costumes). Table 1 illustrates the interaction between the two types of color, and can serve as a guide for what a decorative element or person looks like when subjected to a certain color of light. 

Color of Pigment
Color of Light
Violet
Blue
Blue-Green
Green
Yellow
Orange
Red
Purple
Violet
Deep violet
Dark violet
Dark violet
Violet
Dark brown
Dark brown
Dark gray
Dark violet
Blue
Light blue
Deep blue
Light bluish gray
Light blue
Dark bluish gray
Black
Gray
Blue
Blue-Green
Dark blue
Very dark blue
Dark bluish gray
Dark green
Greenish blue
Dark greenish brown
Black
Dark blue
Green
Bluish brown
Light olive green
Light greenish gray
Intense green
Bright green
Dark green
Dark gray
Dark greenish brown
Yellow
Scarlet
Greenish yellow
Greenish yellow
Greenish yellow
Intense yellow
Yellow orange
Red
Orange
Orange
Scarlet
Light brown
Light brown
Light brown
Orange
Intense orange
Intense orange red
Scarlet
Red
Scarlet
Purplish black
Dark maroon
Maroon
Bright red
Orange red
Intense red
Red
Purple
Reddish purple
Dark violet
Maroon
Purplish violet
Light brown
Maroon
Reddish brown
Deep purple






Table 1: Interaction of Colored Light with Colored Pigment (Courtesy Fuchs, 1929) 

To add to the confusion, additive and subtractive color mixing are also found in the lighting world alone. Additive color mixing refers to the combining of two or more colors to form a new color. As illustrated in Figure 3, the combining of red and blue light sources, for example, will produce a new color, magenta. Subtractive color mixing refers to the filtering of light. When light passes through a single colored gel or filter, only the wavelength corresponding to the color of the filter will pass through it. Figure 4 illustrates this concept.


Figure 3: Additive Color Mixing in Light (Courtesy Gillette, 2000 – Redrawn by author)

Figure 4: Subtractive Color Mixing in Light (Courtesy Gillette, 2000 – Redrawn by author) 

The last important concept of color in lighting design is the meaning of color. It is a well-known fact that  every color has certain emotions attached to it. It is these emotions that the LD tries to enhance in order to make his design more effective.

My final post on lighting design will discuss direction and movement.


References:

  • Fitt, Brian, and Joe Thornley. (2002). Lighting Technology: A Guide for Television, Film and Theater, Second Edition. Woburn, MA: Focal Press.
  • Fuchs, Theodore. (1929). Stage Lighting. Little, Brown, and Company. Retrieved January 31, 2006 from www.rosco.com/us/technotes/filters/technote_1.asp#4.
  • Gillette, J. Michael. (2000). Theatrical Design and Production: An Introduction to Scene Design and Construction, Lighting, Sound, Costume, and Makeup, Fourth Edition. New York: McGraw-Hill Higher Education.

Monday 7 November 2011

Event Lighting Design: Part One

Lighting can be thought of as one of many raw materials the event producer has at his or her disposal. It is the job of the Lighting Designer or LD (usually from a subcontracted lighting supplier), to manipulate the light beams emanating from fixtures or luminaires to achieve the look desired by the event producer or manager. The LD has five qualities of light that can be varied and massaged to do this. These qualities are intensity, distribution, color, direction, and movement. Over the course of the next two or three blog posts, I will cover the basics of these qualities.


Intensity 

In simplest terms, this refers to the strength of a light source. However, there are some other relative measurements that are also associated with a light source and what happens when the light is projected over a distance and strikes an object.


Intensity is the strength of a light source (e.g. the actual lamp inside the light fixture), or the light output. It is measured in lumens or candles. Illuminance is the light level actually falling on the surface of an object being lit. It is measured in lux (metric) or foot-candles (imperial). 1 foot-candle = 10.76 lux. Brightness is the effect of light leaving the surface of an object being illuminated. It is what the human eye actually sees. It is affected by the intensity of the light source, the distance from the source to the object, and the properties of the object (e.g. color and texture). It is measured in foot-lamberts. The figure below illustrates the differences amongst these three terms.




        Light Strength 


Actually, this relationship can be calculated mathematically using what is known as the inverse-square law, E = I/ D², where E is the illuminance in foot-candles, I is the luminous intensity in lumens, and D is the distance in feet between the source and the point of calculation on the surface. For example, using a light source that produces 6000 lumens, the light density on a surface 10ft. away would be 60 foot-candles = 6000/(10)(10), and 20ft. away would be 15 foot-candles = 6000/(20)(20).

Generally speaking, objects that appear bright draw more attention to themselves. Because of this, it is the job of the LD to ensure that those objects needing attention, whether they be performers or decorative, are appropriately bright. 

Distribution 

Distribution refers to the manner in which light strikes a surface and reveals an object.
It can be applied to how objects appear, in that they might be softly lit as part of a larger scene with light that has no sharp edges. On the other hand, they may be individually lit with a small, sharply defined, single light beam.

On another level, distribution can be applied to the appearance of light that uses an image projector of some sort, such as a gobo in front of an ellipsoidal fixture or an actual projector. These in turn produce certain desired images on a surface such as a wall or scrim. 

On a third level, distribution can be applied to the shape of a light beam itself when viewed through smoke or haze effects. 

I will cover color in the next post.