Friday, March 9, 2007

Stage lighting 101

Why Do I need Stage Lighting?

The short answer is, depending on your performance space, you don’t. In fact I have included a tutorial on building your own from halogen work lamps that can be purchased for around ten dollars apiece.

While makeshift lights like these can be fun they are limited. They also can get very hot and tend not to last as long as stage lights. There are three basic kinds of traditional stage lights: A par can or spotlight, a fresnel, and an ellipsoidal.

A par can is just that, a can with a spotlight bulb in it. Without a lens they are very limited in their usage. Rock and roll bands and DJs count these among their favorites. They are the cheapest and easiest to find of all stage lights and you would do well to add several to your kit.

The Fresnell, so named after the scientist who invented the fresnel lens, is the work horse of the theatre. These versatile lights can focus into a fairly tight spot or diffuse the light over a much wider area to provide coverage. They are sometimes equipped with barn doors, or shutters, that allow light to be boxed in or out of a specific area on the stage.

The ellipsoidal is a specialty light. Its lens allows it to be focused very tightly and it nearly always has shutters to further trim the light output and focus it into specific areas. The ellipsoidal is the most expensive of the three and best used for “specials”.

Almost all theatrical lights have these things in common: A can, this is the drum shaped metal container that holds the light, a yolk, this is the U shaped bracket used to attach the clamp to the can. The clamp: This is generally used to attach the light to a pipe or other hanging surface. A lamp (bulb), a plug (these come in several different varieties use Edisons whenever possible as that is the American standard and will be compatible with plugins, extension cords, etc.) , and a lens (the glass piece in the front of the light ) all of these things together make up the lighting “instrument”.

When ordering lights for purchase or rental make sure you know which of these pieces are included in the base price.

Stage lights are controlled by dimmers. These are specialized electronic circuits that allow the brightness of the lamp to be adjusted. Dimmers are not one size fits all. Make sure that the dimmers you buy will put out enough power to run the lights you are using. This is determined by amps per channel. Roughly 100 watts to an amp, so a 10 amp dimmer would be capable of supplying power to 2 500 watt lamps or 1 1,000 watt. Dimmers are in turn controlled by a dimmer or light control board. These come in a variety of configurations, and here again are not the same.

The two major variations in lighting control are analog and digital. If you have analog dimmers you need an analog controller and vice versa. Hopefully you are working with someone who has some expertise in this field or buying from a reputable supplier who knows their job well. A good estimate of how much light you need would be to divide your stage by square footage. If you are going to be using a three color scheme then you will need a minimum of 6 instruments per 100 square feet of stage space. This is enough to allow you some flexibility of design. If all you need to do is shed light on the subject you can make do with half of that.

In addition to intensity light can also be designed using colored gels. They come in an almost infinite array of colors and can be cut to fit. They sit in a gel frame that slides into clips on the front of the instrument.

No comments: