The Basics of Lighting By: William Cronheim

April 8, 2008 by Mobile Beat Staff Writer

What is lighting?Lighting is defined as the perception of reflected light. What does this mean? A person does not see sunlight unless it reflects off something; that is why you don’t see sun beams unless there is dust in the air.

The media with which light interacts is also of great importance. By media I mean a surface, object or particulate matter.

As an example of light interacting with a media and its’ perception by the human eye, I offer the following:

If you were to peer into a room that had the walls, floor and ceiling all painted flat black and a one hundred watt light bulb was hung out of your line of sight, it will make no difference whether the bulb is lit or not. Your eye will not “see” any light because none is being reflected.
In the same room with all of the surfaces painted white even a ten-watt bulb will be perceived as very bright.
Most of you have noticed the difference in the appearance of a light show when there is no particulate matter (smoke, dust, and fog) compared to when there is.
What to start with

The first requirement of any entertainers’ light show is to provide a basic light level for people to see and be seen.

This can be accomplished with various types of fixtures depending on the type of venue, the age of the participants, and of course, budget.

An old standby is the mirror ball with one or more pin spots. This scatters beams of light throughout the venue and will supply enough light to navigate tables, chairs, and patrons. Another approach is the sequencing of a particular type, or combination of types of fixtures, such as pin spots or par cans. Again the underlying desire is to provide an ambient light level.

Par cans come in 3 basic sizes, 46, 56, and 64. Like all light bulbs, the number represents the diameter of the bulb in 1/8s of an inch. Therefore, a par 46 is 4 ½” in diameter, a par 56 is 7″ and a par 64 is 8″.

The par 46 bulb is available in only a 200w size, with narrow, medium or wide beam spreads. The par 56 is available in both 300 and 500 watts again with the three beam spreads. The par 64 comes as a 500 or 1000 watt version and has four beam spreads: very narrow, narrow, medium and wide.

A major consideration in choosing which par to buy for your system will be the size of the venues you anticipate working in, and the amount of power available.

A standard outlet in a commercial building is rated at 20 amperes. A 200 watt light draws about 2 amps, therefore you can have ten 200w lights operating at the same time. With a 500w light drawing about 5 amps, you are limited to only 4 operating at the same time, and with a 1000w lamp it takes only 2 to load the circuit.

All theatrical par fixtures accept gel. Gel is a plastic like material used to color lights. There are a large number of gel manufacturers, each creating up to 180 separate colors. Rosco Products, for example makes 6 different lines of color media, however only 2 are appropriate for use by DJs. These are Roscolene and Roscolux. Roscolene is less expensive and can be successfully used with 200 and 300w fixtures. Roscolux is required for 500 and 1000w fixtures. DJs should experiment with different colors and avoid using the standard red, yellow, blue and green.

Moving on

Over the past several years the popularity of audio activated or audio responsive lights has surged. This is partly because the cost of these fixtures has dropped dramatically while the availability has increased.

The use of these fixtures has greatly expanded the mobile entertainer’s ability to fill large venues with lighting excitement. Combinations of the audio reactive fixtures allow an operator great flexibility in enhancing the music.

Two of the most popular audio activated fixtures are American DJ’s Avenger and Vertigo. Similar fixtures are available from Visual Effects, Ness, Lytequest, Chauvet and other importers, with names such as Derby, Projector, Mushroom, Prancer, Lytetwister, etc.

Many of the audio activated lights utilize the Osram 64514 bulb or the DRA bulb available from G.E., Sylvania and Philips. These 300w 120v bulbs must not be used more than 15 minutes at a time or their lamp life will suffer. This is called “cycle time” – the time in use verses time idle. Both the 64514 and the DRA have a rated life of only 75 hours. The rated life of a bulb is established by turning on 100 bulbs and measuring the elapsed time until half of them have burned out.

Although the inner workings of the Vertigo and Avenger are the same, the effect created by the fixtures is very different.

The Avenger, having one row of lenses, creates a linear effect with movement of the beams across a horizontal plane. The Vertigo, on the other hand, having lenses scattered about a hemisphere, creates a globular effect with movement extending 180 degrees.

Future courses will discuss other lighting and effect options such as pyrotechnics and intelligent fixtures.

Strobes

The use of strobe lights has been in practice since the invention of the xenon tube. There are various effects that can be created with strobes. Using several smaller strobes (egg strobes, pop strobes or curtain strobes) placed around your gear, the effect of shimmering is obtained. Of course using the larger strobes in a darkened atmosphere creates the “stop action” effect. A single flash goes a long way to enhance a particular music change, just as increasing the speed of a strobe burst during a music crescendo adds excitement.

Operators should use strobes sparingly; some patrons will find them annoying. They can adversely affect some people, particularly epileptics; therefore, in general strobe use should be limited to short bursts.

Controlling your lighting

The simplest and least expensive form of lighting controller is the switch panel. These are available in 8 and 12 circuit. Most have simple rear lit rocker switches, grounded outlets and a 15-ampere circuit breaker. The biggest advantage of these units is the minimal expense, normally under $ 40.00. The problem is they require extension cords to be run from your light fixtures to the controller. A typical model of this sort by American DJ is the PC-100, although there are several other manufacturers who make a similar model.

The next level of control enters the land of low-voltage. The least expensive of these units employs the same basic switch box as the switch panel described above, and includes momentary buttons, however, now the switches are switching 12 or 24 volts. This low-voltage signal is sent through a single control cable to a relay pack that contains 8 outlets. The advantages of this system are many. First, there is no line voltage (120v) at the control area. This eliminates the potential for RFI (Radio Frequency Interference) entering your audio system. Secondly, it eliminates multiple long cable runs with their inherent messiness and trip hazards. Third, set up and strike times are cut to mere minutes. Atypical model of this kind of controller is made by American DJ also, the SC-8FC.

A better level of low-voltage control is available. This next generation of controller employs micro-switches, which are more reliable than rocker switches and utilizes 4 channel relay packs. The control section of this system also offers three zones of sequencing in either auto variable speed or audio controlled sequencing. The relay packs used by this system are daisy chainable, meaning control circuits 1 through 4 can control pack after pack after pack, allowing for very large shows to be operated from a single controller. The American DJ model of this type of controller is TP1201, which requires you to use the PP-15’s or the BPP-20’s.

Soft Memory, Memory, Micro-plex and DMX512 control systems will be discussed in future courses.

A beginning system

A typical beginners system might include the following list of materials:

1 – Tripod (LTS-01)

4 – Par 56 fixtures

1 – Vertigo

1 – Avenger

1 – Mini strobe

1 – Low voltage switch system

1 – 4 channel sequencer

The cost of this package will be about $ 800.00

Creating a show

“Build to a finish”

When performing for an audience a magician saves his best tricks for last; so should a lighting operator. If your audience sees everything you have in the first 10 minutes what’s left?

Lights have the capacity to be blended in various fashions. Colors can be either complimentary or opposing in nature, each with a particular effect on the senses. Consider the low end of the color spectrum, the reds, ambers, yellows and pinks as warm colors, and the blues and greens as cold colors. Switching back and forth between red and yellow will make the dance floor seem hot, while switching between red and blue will alternately change the floor from hot to cold.

Just as music ebbs and flows so should your light show. The intensity of your lighting can match the intensity of your music, just as your changes of lighting can match the tempo of your music.

All in all, lighting is about perception. It should be considered a tool just as your speakers are tools. Just as you plan ahead what music to play to achieve a particular behavioral reaction from your audience, so should you plan your lighting effects and segues to match the mood.

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Mobile Beat Staff Writer (228 Posts)

This is the general editors account for Mobile Beat Magazine and Website. Who reads Mobile Beat online and in print and attends Mobile Beat events? DJs, VJs and KJs to start with, especially those who own and operate mobile entertainment services. They provide music, video, lighting and a myriad other entertainment choices for corporate events, wedding receptions, dances and innumerable other gatherings.


Filed Under: Lighting