The Dilemma of General Lighting
April 1, 2011
You cannot avoid it. In the world of multiple-camera television, there comes a time when you will be thwarted in your attempt to make lighting history. The dialogue between the producer and you might go something like this:
"How many people will be seated in your daily talk show?"
"Well, two or three, possibly four, sometimes five."
"Does your lighting person know this?"
"What lighting person?"
The conversation ends with, "Can't you just blast the area with general light that will handle all the situations?"
Immediately, you realize that the possibility of attaining the consummate lighting look you envisioned has been shattered.
To try and save you from such despair, I would like to present a practical solution to this very common situation, and offer some means to ensure a measure of success for this common dilemma.
The method I will describe is a means to satisfy the "general lighting" requirement with some degree of sensitivity. The results will not be spectacular but will meet the pedestrian requirements of constant exposure—without any need for readjustment or day-to-day maintenance. To say that the approach is artful would be a stretch and very presumptuous; it is merely a simple means to an end, a brute force approach.
For my example, I've chosen a typical, successful local station that produces a live, daily morning show. Within the station's studio are two areas devoted to the show. One is a home base for the host and includes seats for the one-to-five people who will be in attendance. The second area, which is our area of general lighting, is large enough to hold a band and a singer, or a cooking show, or a juggler—an all-purpose staging area. A practical size might be an area of 500 square feet, which includes about a 200-square-foot "playing area."
RING OF FIRE
We are going to attempt to light this area with large aperture sources to create a flat-lighted, shadow-less environment from every direction, so that wherever the camera is we have an exposure level that envelopes our talent. Fig. 1 shows our space. The positioning of the side cameras is based upon the coverage provided by the scenic background. If your cooking show has an overhead camera, you will have no problem with coverage—except for the possible problem of shooting your own shoes! The shooting always ends up symmetrical to the set's centerline.
Fig. 1: The Plan Set-Up
It is my opinion that our front-light instruments should have a large aperture, so as to be as "soft" as practical considering number and spacing, the fixture's projected lighting opening being somewhere between the size of a zip and a 4 kW soft light. A good choice is a four-lamp fluorescent unit using 55 Watt twin-tube fluorescents. The opening is about 24 inches square and fitted with a 45 degree cut-off egg crate; a good compromise.
I like fluorescents for their efficiency, long life and very usable consistent spectrum. They also can reach a correlated color temperature of 3,200 K, are economical and have a high Color Rendering Index. To make this all work, it is imperative that your studio includes a theatrical dimming system, and that any fluorescent units you purchase have dimming ballasts that are compatible with your lighting system.
Back lights in roughly the same uniform pattern are necessary to complete the setup. They could incorporate the same fluorescent fixture, but I chose to make miniature soft lights by placing a piece of diffusion (in this case GAM 10-70) on the top and bottom barn doors of 1 kW fresnel spots ( a "diaper" if you will). The final setup is illustrated in the plan.
The spacing of the instruments is quite regular and attempts to mimic a wall of illumination while placing a practical limit upon the number of units. More is not necessarily better. In my experience, using an even number of instruments seems to work out best. Displacing the instruments away from the playing area (see Fig. 1) also has the effect, evening out the illumination level in that area.
TRICKS OF THE TRADE
The success of this "Brute Force" method depends upon one basic trick: Place the soft lights on adjustable hangers so their trim height is quite low. Usually, the front-light units will be between 7 to 8 feet above the studio floor to the bottom of the soft lights. Naturally, you have less choice with the back light. A foot or so above the height of the set is the lowest practical level. I am assuming that the basic grid height in the studio is 16 feet while the scenery is 10 to 12 feet (high).
Fig. 2: These images in color and monochrome show the resultant range of brightness and are typical of the Brute Force method.
Using the larger lamp area to achieve the desired softness results in having much more light than you actually need. In the example shown, the dimmers were operated at 50 percent level which corresponds to about 25 percent of the maximum light intensity. I suggest setting the soft-light intensity as a group with a light meter to your exposure level (usually in the 30 to 50 foot-candle range), and doing the same with the back lights as a group to this level.
THE DOWN SIDE
Fig. 2, displayed in color and then monochrome to show the resultant range of brightness, and is typical of the Brute Force method. There is no control possible to balance any value. The flatness is quite apparent, but actually indicates the success of the method. Note how the blue background is actually brighter than one subject's face. However, due to the stability of today's solid-state sensors, there is no degradation of the face that has less brightness. Desired? Probably not. Acceptable? Yes. Sadly, in order to rebalance we must use means other than lighting. Paint may become your best friend in this situation. This is the price you must pay.
The reader should understand that I do not actually condone the Brute Force method, but, when there is no other path, it provides a viable solution. Let's hope that you will have the opportunity to display the full range of your lighting skills on your next project.
Bill Klages would like to extend an invitation to all the lighting people out there to give him your thoughts at
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