Lighting Design for Modern Houses of Worship

by Richard Cadena

Smashwords Edition

Copyright 2010 Richard Cadena

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Acknowledgements

The lighting business is as competitive, if not more so, than any other. In an industry where margins are sometimes as thin as the walls in a cheap hotel, just about every deal is like a chicken bone being fought over by seagulls on the beach. Still, this industry is not like your everyday dime store merchandise. It’s as different as the world is varied. And it’s the people who make up the industry that make it so. The same people who are battling over an account one minute might be socializing and fraternizing the next. And though we might aggressively defend our accounts, it's not uncommon to help other people in the industry, to offer instruction or advice, or to do whatever we can to help another person advance their career.

After more than twenty years in the industry, I've had more than my share of blessings as the recipient of the kindness of the industry. The many people who have helped me are far too numerous to list, but I gratefully acknowledge each and every one. I hope you know who you are! Still, I would be amiss if I didn't acknowledge the contributions of a select few.

Several years ago, I showed Mark Sepulveda a 3D WYSIWYG lighting model on my laptop, and that eventually led to a long relationship and a strong friendship. It also opened the door to personal and professional relationship with all the very fine people at Maxx Technology in Franklin, Tennessee. Most of the work that enabled me to write this book was a direct result of these relationships. I’d like to thank Mark, and everyone at Maxx Technology, including Jay Hall, David King, Neal Watson, Josh Berry, Martin Culpepper, Andrew Wakeman, Paul Duryee, and everyone else at the organization. It has been wonderful to work with you all.

I would also like to thank my publisher Terry Lowe for his support and tolerance of all my extracurricular activities. You’re the real brains of the operation, I’m just the “pretty face,” but I’m okay with that. (This would be where I would put one of those winking emoticons if this were an e-mail.)

Thank you to my loving wife and daughter, Lisa and Joey Cadena, who always support me in all of my endeavors. (Joey, go clean up your room; love, dad.)

Last, but by no means least, I would like to thank the Lord for all of the guidance and direction in my life.

Table of Contents

Acknowledgements

Table of Contents

Introduction

Chapter 1: Goals, Objectives, Metrics and Methods

What is Lighting Design?

Beginning a Project: What are Your Design Goals?

Visibility

Focusing Attention

Video Requirements

Modeling objects

Creating a Sense of Depth

Aesthetics and Mood

Chapter Two: The Language of the Lighting Designer

Luminous Flux

Illuminance

Luminous Intensity

Photometric Data

Light Levels for Visibility

Light Levels for Video

White Balance

Green/Magenta Balance

Chapter Three: The Mechanics of Lighting Design

The McCandless Method

Key and Fill Light

Rigging Location

Backlight

Chapter Four: Lighting with Uniformity

Blending Fixtures

Chapter Five: The Four-Point Lighting System

Chapter Six: Selecting Light Sources

PAR Cans

ERS Fixtures

Fresnel Fixtures

Automated Lights

Key Light Selection

Calculating the Throw Distance

Calculating the Illuminance

Calculating the Beam Width

Calculating Uniform Coverage

Summary

Selecting Fill Lights

Selecting Backlight

Putting It All Together

Tweaking the Plot

Making Adjustments

Conclusion

Chapter Seven: Completing the Lighting Plot with Diffusion, Color and Aesthetics

Visibility and Aesthetics

The Designer’s Matrix

Sculpting and Painting with Light

Quality of Light

Hard Light and Soft Light

Diffusion

Exposure Values

Degrees of Diffusion

Color Temperature

Mired Shifts

Matching Sources

Chapter Eight: Color Theory

Color Wash

Selecting Color

Color Theory

The Color Wheel

Itten’s Seven Contrasts

Colors in Lighting Design

Primary Colors

Secondary and Tertiary Colors

Complementary Colors

Other Color Harmonies

Split Complementary Colors

Triads

Analogous Colors

White Light

Single Colors and Color Symbolism

Using the Seven Contrasts

Summary

Chapter Nine: Documentation and Paperwork

Lighting Plots

2D and 3D Drawings

Attribute Database

Renderings

Riser Diagrams

Equipment Schedules

Panel Schedules

Breaker Panel Schedules

Dimmer Panel Schedules

Raceway Schedules

Detail Drawings

The Title Block

Appendix A: Glossary

Introduction

“Art strives for form and hopes for beauty.” – Rose Elizabeth Bird

In some ways, today's lighting systems are like the layers of an onion. The outermost layer reveals only the beauty of the visual art of lighting; the toning and color, the defining shapes and shadows, the complex textures, and the graceful ballet-like movements and crossfades. But if we peel away the first layer we will find another layer with a great deal of work and preparation that went into making it look aesthetically pleasing. The right types and numbers fixtures must first be selected and rigged in the proper place, the lighting angles must be just so, the colors and tones must be chosen, and the intensity levels must be set just right. And if we peel away yet another layer of the onion we will find all of the technology behind the system; the computers, high-tech plastics, optical thin-film coatings, compact arc lamps, robotics, networking, and electronics. But like an onion, the heart of every lighting system, and its most important ingredient of all, is its purpose for being. It’s the driving force and the motivation for creating and using the lighting system in the first place.

The lighting designer who designs for a house of worship is in a very special place. That place resides at the intersection of worship, theatre, concert production, and broadcast. To navigate the terrain requires careful deference and respect for the traditions, practices, and desires of the community while exhibiting a solid command of the techniques and skills associated with all of these disciplines. It's challenging, and the accelerating pace of technology doesn't make it any easier.

Rapidly advancing technologies are creating opportunities to refine our production values and offer new ways to approach old problems. Incandescent lamps, for example, have been around for about 120 years and the lamps we use in the vast majority of the ellipsoidal reflector spotlights use virtually the same technology that Swan and Edison invented at the turn of the twentieth century. But new technology is threatening to take its place alongside our tried and true conventional lighting technology. LEDs, compact fluorescent lamps, electroluminescence, and high efficiency incandescent lamps may soon be as commonplace in theatrical lighting as the ellipsoidal is today.

And lamp technology is just the tip of the proverbial iceberg. Not only are we using new technologies in production today, some of which was scarcely heard of 10 or 15 years ago, but we've practically been invaded by media servers, low-res video displays, networking, wireless technology, battery-powered this and Internet-enabled that. No sooner do we familiarize ourselves with one rev of software before the next rev is thrust upon us.

The good news is that there is hope for those of us who are willing to put forth the effort, and it's not as difficult as we might think. The key is to understand the fundamentals underlying the technology. To the initiated, any new technology is but a manifestation of an existing principle in a unique presentation. LEDs are another light source, albeit one with different characteristics than an incandescent lamp. But they follow the same principles, just as do compact fluorescent lamps, electroluminescent sources, and any other emerging technology.

The purpose of this book is to provide a solid foundation of fundamentals that apply in any given situation and that will adapt to any new technology. It is a guide to the future of designing with light.

Today’s lighting designer does indeed face many challenges, but the designer working in a place of worship has the advantage of working for a higher purpose. And that, along with a grasp of the fundamentals, will get us over the hurdles of technology and the challenges of designing with today's lighting systems.

Chapter 1: Goals, Objectives, Metrics and Methods

"Your purpose explains what you are doing with your life. Your vision explains how you are living your purpose. Your goals enable you to realize your vision." - Bob Proctor

We live in an ever increasingly visually stimulating environment. A vast number of images and messages vie for our attention in an increasing number of mediums. We are constantly bombarded with aural and visual messages from television, smart phones, billboards, newspapers, magazines, the Internet, and even t-shirts and sneakers. To divert and hold another person’s attention today is no easy task.

For the lighting designer in a house of worship, the objectives are easy definable: focus and hold attention; provide enough illumination for the congregation (both for the young and the elderly) and possibly for video; and make it aesthetically pleasing without creating a distraction from the message. But to implement these objectives is not always as easy as it may seem. There are typically those contentious issues like budget and committee approvals that have to be addressed even before a lighting design is drawn up. Then there is the little matter of “design” that must first be understood and then carried out.

Fortunately, much of lighting design is objective and measurable. Illumination levels, uniformity of light levels across a specified area, color temperature (the balance between red and blue in the spectrum of white light), and color rendering are all examples of concrete measures of lighting quantity and quality. These are hard and fast objectives that we can work toward using established methods, known relationships, and a little calculation. If we get it right then we can manipulate the visual environment in order to achieve our goals and objectives.

On the other hand, there is another side of lighting design that is more subjective and perhaps a little more challenging to define. What "looks good" is a matter of opinion, and perhaps even more elusive is the question of how to manipulate our lighting tools to create a “desirable” or "pleasing" look. There are a variety of ways to change the look and feel of a scene – using color, diffusion, interference medium (fog or haze), lighting levels, lighting angles, etc. These are all tools and techniques that we use to sculpt the visual environment.

When it comes to creating a visual environment in a place of worship, the lighting designer is typically subordinate to a higher purpose. Our job as a lighting designer is to create the right visual environment to support the higher purpose without eclipsing it. The effective lighting designer is one who can use the available tools to the best advantage within the scope of purpose. It is a unique application using many of the same tools as other lighting disciplines. With some knowledge, some practice and a little experience, we can be an effective lighting designer who works to serve the higher purpose.

What is Lighting Design?

Lighting design is the process of using light to shape the visual environment in order to achieve a stated objective or set of objectives. The objectives can range from the subjective, such as “livening up” a room, to the more concrete, such as increasing visibility for the elderly. A lighting designer typically has a range of tools from which to choose, and understanding how those tools work and how best to apply them to a specific situation is a designer's stock in trade. Lighting design is not an exact science; rather it is a mix of the subjective and the objective. If you asked 10 different lighting designers the best way to approach a lighting project you’re likely to get 10 different solutions. There is no one right or wrong way to do it. There are many different approaches that are equally valid and might yield equally good results. The final criteria are the achievement of your stated objectives and a good (or great) final result. As we grow in the lighting design field, we might learn several different approaches to similar situations.

Lighting design can be learned and with practice it can be honed and improved upon. Once we understand the basics, then more research, experience, experimentation, and exchanging ideas with other lighting designers will be our best teachers. The more we work with lighting the more techniques we will develop and the more we will train our eyes and sharpen our skills.

One way to train your eye for lighting is to look out the window when you’re flying at night. When you are on your final approach and you are close to the ground, there are lots of lighting “canvases” to see and observe. For example, you can compare and contrast the color temperature, intensity, and uniformity of the lighting in sports arenas, parking lots, and city streets. After you land, it’s fun to drive to one of your targets and observe the same spot from the ground.

There is much to know about lighting and lighting design, and with the rapid pace of technological change, there is more to know every day. But as long as we understand the fundamentals then we can more easily deal with changing technology and changing products. Once we understand the characteristics of light then it doesn't matter what the light source is; it can be incandescent, fluorescent, discharge, LED or anything else, and the fundamental principles such as the "quality" of light still apply. The key is to have a firm grasp of the basic concepts.

Concepts:

• Lighting design is the process of using light to shape the visual environment in order to achieve a stated objective or set of objectives.

• Color temperature is the balance between the red and blue content in white light. It is measured in Kelvins; incandescent lamps have a color temperature of 3200K and daylight has a color temperature of about 5600K.

Words to know:

• color temperature - the balance between the red and blue ends of the spectral power distribution of a light source

Figure - Design goals can be defined in terms of visibility, contrast, uniformity, quality of light, modeling, depth, and aesthetics.

Beginning a Project: What are Your Design Goals?

Abraham Lincoln once said, “Give me six hours to chop down a tree and I will spend the first four sharpening the axe.” This advice is not only appropriate for clearing land but it's also very appropriate for lighting design. Before you begin your lighting project, you should bring into sharp focus your goals and objectives. What is it that you are trying to achieve with the lighting system? Is it simply for visibility or is there more to it than that? The design criteria should be tailored to the job at hand. Some of the criteria that you might include in your stated objectives are outlined below.

Visibility

Visibility is one of the most common lighting design goals. If you are lighting a platform with a speaker or other subjects, then the subject(s) should be lit to a certain level of illuminance as measured in lux or footcandles; otherwise it will be difficult to make out facial features and expressions, which could diminish the impact of the delivery. Our visibility goal should be quantified by the amount of illuminance we are targeting. We will discuss this in detail later on.

If there is image-magnification or video acquisition, then the illuminance requirements will change because a video camera has different lighting requirements than the human eye. You should consult with the video crew to find out their expectations ahead of time.

Focusing Attention

Over the course of a typical service, it’s natural for people’s attention to drift. By keeping the platform and the subjects well lit and keeping the peripheral areas at lower illuminance levels, we can help keep focus attention where it should be. Focusing attention is as much a function of the lighting contrast, that is, the difference in illumination levels between the areas of interest and the areas of less importance, as much as it is a function of overall illuminance levels. If everything in a room is lit to 300 footcandles, the eye has no focal point and there is nothing to draw the eye or compel it to stay focused on the subject. If, on the other hand, the subject is lit to 150 footcandles and the rest of the room is lit to 25 footcandles, then the eye is more likely to stay focused on the well-lit subject rather than wander around a darker room.

Video Requirements

Most modern houses of worship today are reinforced with live video, either in the form of image-magnification (I-mag) or “B roll,” which is pre-produced content for playback. If the sanctuary you are lighting has video cameras, then the lighting requirements could change dramatically. The light levels, uniformity, color temperature, and direction of lighting are all subject to critique and debate by the video crew. It’s best to communicate early and stay in close communication with them to determine their requirements and expectations. Ask the head of the video department about their expectations for light levels on the platform. Modern video cameras can operate at lower light levels but using higher lighting levels still produces a better signal-to-noise ratio and a less grainy picture.

One of the biggest issues to deal with when video is involved is the uniformity of light across the platform, particularly if the subject likes to move around a lot or if there are many subjects spread across the platform. If the light level varies from one spot to the next then the video engineer will have to “ride the iris” or “shade the cameras” to correct the exposure levels every time the camera moves. When that happens then the lighting crew will usually hear about it.

Figure - Video and image-magnification alter the lighting design criteria.

Modeling objects

One of the main objectives of lighting design is to give form and definition to the subject. This is commonly accomplished by "modeling" the subject with light. That simply means that you can accentuate the texture and form of an object or a subject by lighting it at certain angles and carefully controlling the intensity of the various lights. Lighting an object only from the front tends to make it look to the human eye as if it is flat. It hides the definition, features and depth of the subject. On the other hand, a video camera tends to accentuate the very shadows that give an object shape and form. To compound the issue, a video camera has the ability to zoom in on the subject and magnify the size of shadows. Therefore, we have to distinguish whether we are lighting primarily for the human eye — i.e., the congregation — or whether we're lighting for the camera. If we're lighting for the camera then we might want less modeling and more flat lighting. But if we're lighting primarily for a live audience, then we can model the subject so that we can illuminate its distinguishing characteristics and make it look more natural from a distance.

Figure - Lighting can enhance the audience’s experience by creating an aesthetic mood with color and projection.

Creating a Sense of Depth

Lighting can also create depth and give the appearance of space. By controlling the intensity of light at different areas of the platform, for example, highlighting the downstage area and dimming the upstage area, we can give it spatial reference and definition. That helps keep it from looking as if all of the subjects on the platform are on top of each other. We can also create depth by using backlight to highlight the form and shape of a subject.

Aesthetics and Mood

By using color, patterns, and projections, we can change the aesthetics and influence the mood of the audience. It can be bright and cheery, dark and moody, or we can simply paint a picture with an interesting aesthetic appeal. Of course, any two people may not necessarily agree on what constitutes an "aesthetically pleasing" look, but there are certain principles to help guide us in this regard. For example, the color blue is most difficult for the human eye to focus, so it tends to obscure features. Yellow is a very bright color. The combination of blue and yellow creates a strong contrast. There are many other principles of colors and color combinations that are very useful as a starting point in lighting and scenic design. We will discuss these in more detail later on.

In a perfect world there would be a very clear delineation between each of our objectives; in the real world there is a lot of gray area. The experienced designer recognizes the conflicts, takes into consideration all of the design criteria, and makes design choices based on a balanced evaluation of the needs of the production. The end result should satisfy all of the competing goals and objectives.

Concepts:

• Set design goals before starting a lighting design project.

• Define your goals in terms of visibility, contrast, uniformity, color temperature, modeling, depth and aesthetics.

Words to know:

• illuminance - a unit of measure of the density of light falling on a surface area. Illuminance is the luminous flux (lumens) divided by the area. If the area is measured in square meters then the value of illuminance is given in lux and if the area is measured in square feet then the value is given in footcandles

• lux– a unit of measure of illuminance equal to one lumen per square meter in the metric system

• footcandle– a unit of measure of illuminance equal to one lumen per square foot in the English system

• contrast - the juxtaposition of two different design elements

• I-mag - short for image magnification, a term used for the projection of video in order to magnify the subject and bring it closer to an audience

• B-roll - a video term describing pre-recorded content used to feed a video projector

• signal-to-noise - the ratio between the voltage of a video signal and the voltage of the background noise in the signal

• “ride the iris” - a term used to describe how a video engineer constantly adjusts the aperture of a video camera to adjust for differences in lighting levels

• “shade the camera” - a term used to describe how a video engineer adjusts the settings of a video camera to adjust for differences in light levels and other changes

• modeling - the use of light projected onto a subject at an angle in order to highlight and define the shape and form of an object

• aesthetics – a pleasing appearance or effect

Chapter Two: The Language of the Lighting Designer

“And God said, 'Let there be light,' and there was light.” - Genesis 1:3

The lighting designer needs to be concerned with a handful of lighting measurements; how much light is produced by a luminaire, how strong the light is in a particular direction, how much light is distributed in a certain area, or how much light is reflected back to the eye or to a camera. Ultimately, the main reason we need to understand these measurements is so that we can use them to decide which lighting instruments to use and to set our goals and objectives. We also need to understand them so that we can measure how well we’ve met those goals and objectives.

The photometric data provided by luminaire manufacturers can be presented in several different formats and we need to be able to decipher it given any of its many forms. We should be able to turn the data into useful information about the size and intensity of the beam or field at a given throw distance. Before we start laying out our light plot, we will look at some of the metrics of lighting, specifically the measure of luminous flux, illuminance, luminous intensity, and luminance.

Luminous Flux

Luminous flux is measured in lumens and it tells us how much light is coming from a lamp or luminaire. Lamp manufacturers often supply data about the total luminous flux for a particular lamp but once it goes in a luminaire, some of the flux is lost to the optical inefficiency if the fixture. Therefore, we can think of the luminous flux of a luminaire as the total luminous flux provided by a lamp source minus the luminous flux that the reflector is unable to capture and redirect out of the fixture and that which is lost to the inefficiencies of the lenses and optical components such as gobos, filters and the like.

Illuminance

Illuminance is the amount of light falling on a surface in a unit area. It is most often the metric used to design and measure the performance of a lighting system. In the English system illuminance is measured in footcandles (lumens per square foot) and in the metric system it is measured in lux (lumens per square meter). To calculate the illuminance from the luminous flux produced by a luminaire, you can divide the luminous flux by the area over which the light is spread.

Illuminance = luminous flux ÷ area

If the area is given in square meters, then the result will be in lux; if the area is given in square feet, then the result will be in footcandles.

Sometimes the area in question has to be calculated based upon the beam angle or field angle of the luminaire. We will discuss this in greater detail later on.

If we think of the luminous flux as a can of paint (the can of paint is the total amount of light produced by the luminaire), then you can think of the illuminance as the thickness (brightness) of the paint applied to a canvas. You can spread it very thinly and cover a large area or you can put on a very thick coat and cover a smaller area. Similarly, concentrating all the light from a fixture in a small area results in higher illuminance and spreading it out in a large area results in lower illuminance. A handheld illuminance meter, such as a Minolta T-10, can be used to measure the illuminance of a given beam or field.

Figure - Illuminance is related to the luminous flux and the area onto which the light falls.

The amount of illuminance required on a subject on a platform in a sanctuary varies from about 80 footcandles to 150 footcandles or more, depending on the circumstances. The presence or absence of video cameras will influence the illuminance requirements, but bear in mind that as a general rule of thumb, you should light the platform to at least twice or three times the illumination level produced by the house lighting in order to preserve the contrast you need and focus attention on the platform. Remember that it’s easier to over-design the lighting and use dimmers to lower the light levels to meet the requirements of video and the congregation than it is to add lighting and electrical after the fact. Dimming incandescent lights does lower their color temperature and tones them towards the red end of the spectrum, but that can be easily addressed by adding color correction gels. We should also keep in mind that lamps will lose intensity over time due to lumen depreciation. So we should always build in some overhead to make allowances. For these reasons, it is usually sufficient to design a church lighting system to target an illuminance level of about 150 footcandles or more. Over time, the actual level may drop to 100 to 125 footcandles.

Luminous Intensity

Luminous intensity, as the name implies, is a measure of the intensity of light at a given point and in a certain direction. If you stand, for example, on the platform and look directly into a light source, then you can get an idea of how bright the source is. If you then look away from the light source while you're standing in the same spot, the intensity will be much less, assuming you're not looking into another light source. This is an example of gauging the intensity of light in a particular direction. We can quantify that measure by using the luminous intensity yardstick.

Luminous intensity is measured in candelas and it is sometimes used by luminaire manufacturers as a way of quantifying the intensity of the light produced by their instrument. This is very different than the luminous flux metric.

Given the luminous intensity of a particular lighting instrument, you can calculate the illuminance in a certain direction and at a particular throw distance by dividing the luminous intensity by the square of the throw distance. Put another way, the luminous intensity drops off as the square of the throw distance. This is known as the inverse square law.

Illuminance = luminous intensity ÷ distance squared

For example, if a luminaire produces 100,000 candelas at a distance of 10 feet, then the illuminance will be 1000 footcandles. Note that if we double the throw distance to 20 feet, the illuminance drops off by a factor of four to 250 footcandles.

Photometric Data

Manufacturers of luminaires usually provide photometric data that tells us how much light a fixture produces. This data is sometimes presented in the form of a chart showing the beam or field diameter and illuminance at various throw distances. In some cases the photometric data is presented as a single figure, such as the luminous intensity (along with the beam or field angle). The illuminance at any given distance then has to be calculated using the inverse square law. Alternatively, some manufacturers provide IES files, which are iso-illuminance charts formatted according to the standard set forth by the Illuminating Engineering Society. IES files require the use of a software package designed to make use of the formatted photometric data.

Figure - Typical photometric chart showing throw distance, field width, and illuminance.

Figure - Iso-illuminance graphic showing lines of equal illuminance.

Light Levels for Visibility

If there is no live video reinforcement (as opposed to pre-recorded video playback), then the lighting criteria are different than a service with video cameras. The typical considerations are illuminance, modeling, depth, aesthetics and focus of attention. The uniformity across the platform is less of an issue because the human eye is much more forgiving than a video camera. By the same token, the color temperature (balance between red and blue) and the balance between green and magenta is less of an issue with a live audience. In most cases, 100 to 125 footcandles is sufficient provided the ambient lighting can be controlled. In addition, it’s important to use at least three-point lighting (see the McCandless Method below) to model the subject. Layering the lighting to create depth on the platform helps focus and keep attention where it should be. And finally, a bit of color splashed on the set will give the services an aesthetic appeal.

Light Levels for Video

When a service includes live video reinforcement, the lighting design becomes much more critical and demanding, and a number of new design criteria need to be considered. In addition to meeting the minimum illuminance levels, modeling, creating depth and providing aesthetic appeal, the key (front) light should be as uniform as possible across the acting area to avoid hot spots and cold spots on video. The smallest variations in illuminance can produce noticeable problems on the display, even if they are not noticeable with the naked eye. If the acting area is small and the speaker is not a walker, then it’s relatively easy to provide uniform front lighting with one or two Lekos or a couple of PAR cans. (Always remember to light the area around a podium as well as the podium in case a guest is called to the front of the stage). But if the acting area is large, then it becomes a bit more challenging to provide uniform lighting across the platform with several fixtures. (We will discuss this more under the topic “4-Point Lighting.")

Modern video cameras are much more sensitive to light than they used to be. Therefore, they can yield very good results with much less illuminance. However, you should be keenly aware of the tradeoffs between capturing video in bright lighting conditions and low light conditions. In bright light, the video engineer shades the camera such that the iris aperture is smaller; in low light the iris is opened more to allow more light to reach the video sensors. The way the background renders on the video monitor is dramatically affected by the size of the iris. A large aperture creates a short depth of field and the background is thrown out of focus. A smaller aperture creates a longer depth of field and the background is rendered in sharp focus.

If you are lighting a subject who is standing at a podium or wandering the platform delivering a message, it is very distracting for the viewer when the church elders or the choir is in sharp focus in the background. It’s especially distracting if they are talking, moving, or otherwise drawing attention to themselves when the attention should be focused elsewhere. For that reason, it is often more effective to decrease the illuminance on the platform so that the iris can open more and the background will be a soft blur.

On the other hand, using higher illuminance levels still translates to a higher signal-to-noise ratio on camera. But always defer to the video department because they are the ones who are ultimately responsible for the look on video.

Figure - Layering the light helps create depth and separation. In this photo, Mark Schultz is the center of focus while most of his band is under lit to keep them in the background.

White Balance

In addition to uniformity, the video camera should be “white balanced” to the lighting system so that all colors render correctly on the display. If there are both tungsten lamps (color temperature 3200K) and daylight lamps (color temperature 5600K or higher), then one group of them will have to be corrected with gels to match the color temperature of the other group. Some designers prefer to balance the camera to tungsten and correct the discharge lamps while others prefer to balance the camera to daylight and correct the tungsten lamps. Occasionally some lighting designers split the difference and balance everything to 4000K or 4200K. If there is an overwhelming number of one type of lamp versus the other, then your choice may be obvious; go with the color temperature of the dominant source. On the other hand, your design choice might be influenced by the ambient light conditions or by the video crew. If the event is outdoors or near large windows with lots of natural light, then it might be advantageous to balance to daylight. But during an indoor event with lots of conventional lights and few discharge lamps it would be easier to balance the lighting to tungsten.

To correct to tungsten, use CTO (correct to orange) filters and to correct to daylight use CTB (correct to blue) filters. Each of these filters is available with varying amounts of correction. One full CTO, for example, will correct a 5600K source to 3200K, while a half CTO will correct daylight to about 4400K. Color correction filters are typically available in 1/8, ¼, ½, ¾, and full values.

Green/Magenta Balance

Sometimes discharge lamps in certain automated lighting fixtures are tinted towards green and away from magenta. It can be caused by the infrared (heat) filter in a fixture or the coating on a dichroic glass reflector. Whatever the cause, it creates problems, particularly for the video crew. It may or may not be obvious to the naked eye but if there is a green balance problem it will show up on video. A vectorscope (an instrument used by video engineers to measure color, both hue and saturation, in a video signal) can be used to objectively determine if there is a color problem and, if so, just how big of a problem it is.

During the setup of the video cameras, a camera is balanced by pointing it to a white card that is illuminated by the key light or video wash. The video engineer monitors the signal produced by the camera and makes adjustments to the camera based on what is seen on the vectorscope. In the picture below and to the left, a perfectly balanced camera reading a white card displays a signal at the center of the vectorscope. In the picture to the right, the signal falls in the area of the green, indicating that the lighting needs to be corrected towards magenta. A minus green filter will address the problem by shifting the color away from the green spectrum and towards the magenta spectrum.

Green is not a flattering color for human skin, so this can be a critical issue, particularly if there is video present in the production.

Figure - Vectorscope showing balanced white light.

Figure - Vectorscope showing white light with an imbalance between green and magenta.