Lighting Basics-Part 1

Lighting-it can be your best friend and your worst enemy. At times, it seems to have a mind of its own, taunting your knowledge. It is a constant challenge...and this is why it is my favorite area to focus on.

If you're like me, lighting is an area that you avoid because you don't understand how it works. I finally had to face it in college as part of the degree, and what I found is that once you understand some fundamental basics about light, it becomes a joy to work with...a joy tempered with frustration as you try and build on what you have learned before.

Without getting into the science of things, let's look at some of the basic terminology in lighting as it applies to the theatrical and venue-based systems:

Lamp: What some would call the bulb, it is the source of light in a lighting fixture. There are tungsten, halogen, fluorescent, LED, and many more. The most common that you would deal with in a church situation are the four I mentioned.

Fixture: The unit that houses the lamp and serves as the device that we are used to seeing hanging from a lighting rig.

Lighting Rig: A group of fixtures attached to the same mounting apparatus that provides illumination for a program. For example, you would have a stage rig that consists of fixtures that light the stage area from an overhead position.

Yoke: An arm, usually metal, that extends from the fixture that allows for mounting to an external support structure. Also used as a verb to describe how you are mounting a fixture (e.g. "You'll want to yoke that straight out to clear that rail.").

Par: A fixture that relies on a parabolic reflector to send light from the lamp down the barrel; a good general lighting fixture, it often lacks the control of the light beam that other fixtures employ.

Ellipsoidal: Similar to the par, but using a more efficient ellipsoidal reflector (hence, it's name), it often allows for "shaping" of the light beam through shutters installed in the barrel, allowing for precise positioning of the edges of the light beam. Also allows for "focusing" of the light beam, from soft to hard edges.

Mover: A fixture mounted on a yoke that allows rotation in the vertical and horizontal axes. Usually comes with other light beam modification options, such as color changing, "gobos," or patterns the light beam shines through to create a projected pattern, and others effects. These are some of the most expensive pieces of your lighting package. Always has its own dimmer, so you do not plug these into a dimmable circuit.

Dimmer: Conventional, or white, lighting fixtures, such as pars and ellipsoidals cannot dim up and down by themselves, so they must be attached to a device that alternates the electrical current being delivered to these fixtures. This device is called a dimmer, and usually consists of more than 1 dimmer per device. If a dimmer has four circuits, then you can plug four fixtures into that dimmer. There are exceptions that I will address later.

DMX: Digital Multiplex, the control protocol developed to control lighting devices. It was developed in order to provide a standard control protocol for all theatrical lighting manufacturers. Naturally resistant to interference due to the digital nature of the protocol, it can be run long distances, and is a very useful tool. Allows the operator 512 channels of control per "universe." For example, if you have 20 lights that you want to dim up and down, you will require 20 DMX channels to do so. For a standard RGB (Red, Green, Blue) LED (light emitting diode), you will require at least three DMX channels (Red-Dim, Green-Dim, Blue-Dim).

RDMX: A newer "amendment" to the DMX protocol, it allows remote control of RDMX-compatible equipment. Options like remote device management and remote DMX addressing are possible, depending on your equipment compatibility. It's even possible to receive status updates from your fixtures regarding temperature, lamp life, and more.

Universe: A full 512 channels of DMX. With lighting systems getting more and more complex, it has been discovered that often-times more than 512 channels of control are necessary, particularly if you're dealing with close to 100 moving lights, each requiring 16 DMX channels...or more. A DMX universe simply contains a full 512 channels of control and makes it easier to divide up where certain fixtures reside (Universe 1, Channel 56 vs. Universe 2, Channel 56). The same channel can be assigned in a different universe to a different fixture. It's quite ingenious!

Ok, so that covers some of the basic terminology. If I mention something that doesn't make sense, please, shoot me an email and I'll be happy to explain it.

Let's talk electricity. First, if you don't understand it, either learn or hire someone to do the electrical work for you. I know enough to be able to converse with electricians up to a point, after which I'm lost. Remember what I mentioned in one of my earliest posts-know what you don't know, and find someone who does. I personally have a healthy respect for electricity, and as such, don't mess with something I don't know about.

So, just some basic numbers for you for a 120v system (unfortunately, many lighting rigs require 240v service due to the sheer number of moving lights and other elements).

10amps=~1200watts
20amps=~2400watts

Therefore, if you have 6 575w ellipsoidal fixtures to put in and you want individual control over each fixture, you will need a dimmer with 6 10A circuits. You might thing that you could put two lights on one 10A circuit, because you would still be below the 1200 watts. However, you never want to fill your circuits all the way. You notice that I said it was around 1200 watts, not 1200 watts exactly. There are lot of other factors that go into this, but again, ask and electrician that is familiar with theatrical lighting (there are great resources available nationwide, just look up lighting rental facilities and ask to speak to someone about electrical needs).

Ok, so that concludes Part 1 of Lighting Basics. There is SO much more to lighting, this might take 3-4 posts just to cover the basics. Remember, you can have the same video system in many different facilities because the components in that system will always operate the same, without much thought to external influences. Audio and lighting systems must take many things into consideration at the facility itself, and hence why audio and lighting consultants have to create custom systems for every venue.

As always, please let me know if you have any questions I might answer, and feel free to pass this along!