The Lighting Triangle

LightingNow that you have your lights it's handy to know how to use them. Turning them on and pointing them at your subject is a good start, but if you really want to get the most out of them you can use what's known as "the lighting triangle."


Unlike its Bermuda cousin, the lighting triangle doesn't make stuff disappear... it makes it show up! At least, it makes it more visible, more dynamic, and more dramatic on camera.

Check out the diagram below:

Lighiting Triangle
 
It works like this. First you have the "key light," which is the main light for your setup. It should be off to one side and slightly angled on the face of your subject. This is the light that shows most of the details.

Next is the "back light." As the name implies, this one goes behind the subject and casts a nice little halo of light in their hair and shoulders. This is what's known as a "rim" in professional circles... it helps to separate the subject from the background and highlights their shape and silhouette.
Finally there's the "fill light." This is a flood light that hits the subject from the opposing side from the key light. It should be more diffused than the key light, allowing the shadows to stay on the subjects face but brightening them up enough to let the detail show through.

If you use the lighting triangle I guarantee you that you'll notice your videos looking a little more "professional." This is handy for interviews, but it can also be used for what we call "product shots." In other words, footage of an item like a birthday gift or a new car or whatever.
And even though it's not always required, sometimes you may want to throw a fourth light into the mix. This one would be the "background light," and it does exactly what the name implies... aim it at the background to highlight it more.

Those are some basic lighting tips and if you play with them they'll take you a long way. You can also try things like throwing colored "gels" on to your lights (available at a theatrical supply store). Just like anything else when working with video the trick is to be creative and inventive.
How To Use: Basic Light Set-Ups:
    Basic 4-Light Set-up with hair light added:

Lighting 2
 
Basic 4 light setup with added hair light. 2 lights in front are directly lighting the subject, the key and the fill. The key on the left is closer and brighter. The fill on the right "fills" in the shadows on the right. The difference in brightness between the two lights produces a "lighting ratio" that gives the face shape compared to a single light straight on. If there is no ratio the lighting is considered "flat" and looks less 3 dimensional. Two lights light up the background. Fluorescents are especially good at providing an even lighting for green screen or blue screen work. The hairlight is a smaller light that provides highlights in the subjects’ hair, it is the small round fixture close to the background and would be over the subject directed down.
Simple 3 Light Set-up, optional hair light:

Simple 3 light
 
This is a simple set-up with 3 lights, still suitable for green screen. 1 light in front lights the subject, the light should be placed so light hits both sides of the subjects face, yet slightly off to the side to provide some 3-dimensional modeling of the face. A fill card or reflector can also be used on left side to fill in shadows. Two lights on the background provide for even keying.

3 Light Interview Setup:

Interview lighting
 
This setup was used for a television commercial production promoting a vocational school. I used 3 lights of equal power: a main at full power, a hair light in the vertical position with barn doors at full power and a background light to illuminate the action behind the main talent. The main light was just off camera left. I was looking for minimal modeling on the talents face. It saved time and allowed me to use the 3rd light on the background. I find this setup more pleasing on females; males look better with a stronger contrast achieved by moving the main light forward and left. The hair light provides good separation from the background and the background light shows detail but is 1.5 f/stops darker than the main subject. This was done to show the action without overpowering the main subject.
This project was a testimonial TV commercial but the setup works equally well for a newscaster standup or documentary interview.

Kenny Valenzuela, Director of New Business Development and Technical Support, has an MBA in Marketing from Tulane University and a BA in Radio-TV Film Production from San Jose State University. He was a freelance video producer and editor prior to joining Prompter People.