Lighting up the stage

Stage lighting is no longer a matter of simple illumination as it was less than 100 years ago. Lighting design is the process of using the qualities and functions of light to affect people, objects and space. The qualities of lighting are intensity, form, color and movement. The functions of lighting are visibility, mood (atmosphere), composition and motivation.

Any successful lighting design depends on the operator understanding the equipment they are using and the methods used to create the desired effect.

The Fixtures
Lighting fixtures come in two basic types: fixed and adjustable focal lengths. Stage spotlights all come with specific 'beam spreads', usually referred to as the; beam, field & cutoff angles. Typically focal lengths range from 5 to 150 degrees. If you need to project light to a certain size or the pool of a spotlight to be a specific width, you need to find out the beam angle.

Beam Angles
First determine the required distance at which the fixture will be used. This is often referred to as throw distance and is measured from the lighting fixture (or hanging position) to the center of the object, illuminated.

When lighting acting areas, the designer will usually measure the distance, to the actor's 'head height', (approximately 6'/1.8m. above the floor). When lighting an actor seated in a chair, then the distance is measured to the nose of the seated actor. The distance may be specified in either meters or feet.

Next, the designer must specify the beam diameter (the size of the lighting pool) that is required to light the actor or scenery at the given distance. When lighting an acting area, the beam diameters required are usually specified at the actors head height. For example, a down light mounted at 20' above the floor might provide a 9' diameter pool on the floor, however, at 6' above the floor, it provides the actor with less than a 7' diameter pool, or 'workable' acting area. When not lighting the actor, distance and beam diameter are usually measured to the center of the actual scenic element being illuminated.

Rather than confuse readers with calculations here, there are several beam calculators available on the internet, and even on iPhone applications. Google is our friend here!

The Range
A stage lighting rig for a theatre show consists of a range of the different spotlights, plus other types of lights and equipment. Fresnels and PC’s (Prism Convex, Pebble Convex) are most often used flown over the stage with the narrower beam angles of the Profile Spotlights rigged out in the auditorium. As mentioned above, choosing the right spotlights involves knowing the throw distances and required beam size of each of the lights you need for your show.

Fresnel
A light which uses a circular reflector and which is named after the lens which it uses. The Fresnel gives a very soft edged beam as well as spreading a great deal of light outside the beam (spill). The light can be focused in order to alter the size of the light beam but it cannot project gobo images. Despite being not particularly efficient, the Fresnel is a good light for stage lighting, especially at close & medium ranges to the subject.

Profile
An efficient light which uses one or more lenses and an ellipsoidal reflector to focus the light into a sharp beam. They usually have a longer body than Fresnel and can be focused to form a sharp circular beam with little spill. This sharp beam enables the light to project gobos as well as using shutters to project a specifically shaped light beam. Zoom profiles are available, giving an adjustable beam size. Profiles are suited to projections and for lighting at medium and long ranges from the subject.

PC (Prism/Pebble Convex)
A cross between a Fresnel and a Profile which uses a rough reflector to diffuse the light, producing a beam which is similar to an out of focus Profile. The PC gives slightly more intensity efficient than a Fresnel and also produces less spill and a larger beam size range.

Parcan
This light is built around it sealed lamp, consisting of lens, filament and reflector. This arrangement produces an extremely robust bulb able to operate at high temperatures and for short flashes. The Parcan has a metal tube around the front of the bulb, giving a very powerful light which weighs little but produces bright, white light. The beam cannot be focused and is a soft ellipse with little definition. The Parcan is suited to a wide range of duties, most notably band lighting.

Flood
An uncontrolled light which produces a very large area of illumination. It has no lens and relies on a large reflector to direct the light out, resulting in a cheap and efficient light which produces enormous amounts of spill. An asymmetric floodlight directs more light upwards and is used to light flat walls (or cycs). This means the part of the surface furthest away gets more light and so the wall is evenly lit. Floodlights are generally used to produce large colour washes.

LED Lighting
LED fixtures have many advantages over the aforementioned lanterns that make them attractive in stage lighting. Because the LED uses a fraction of the power of an normal lightbulb, the power consumption of LED fixtures is very small, and therefore more environmentally friendly. Although LED stage lighting does produce heat, the fixtures produce light without getting extremely hot - there are some environments where the low heat properties of LED stage lighting are desirable.

The most common way for LED lights to be used for stage lighting purposes is using a combination of different coloured LEDs. A fixture with all three three lighting primary colours, Red, Green and Blue (RGB) LEDs blended together in different combinations gives the lighting designer loads of colour choices. This is using a principle called Additive Colour Mixing, where the coloured LEDs mix on any surface that reflects the light.

Lighting Control (DMX)
DMX controlled lighting systems are used in many professional settings. Technically, DMX is an abbreviation for DMX512-A, the ESTA (Entertainment Services Technology Association) standard for controlling lighting equipment and related accessories. A wide variety of lighting control consoles, controllers and other devices that output DMX signals can be used to connect to an even greater variety of lighting fixtures and accessories.

External Hire
Your theatre may have enough lighting fixtures, dimmers and cables for your production, but sometimes you need to hire in stage lighting - maybe for special effects in a particular production or perhaps in a larger performance space that needs more stage lights to create the desired effect.

There are many lighting and staging hire companies that will offer a complete service - from simple stage design through to wholesale consultancy and advice on the functionality of all performing spaces in your school. In part two of this article, we will take a look at effect lighting, portable and fixed staging systems, acoustics, theatre sound systems and much more.

Further information
The Association of Lighting Designers - A professional body representing lighting designers working in the live performance industry in the United Kingdom and many other parts of the world.
www.ald.org.uk

The Blue Room - A UK based forum frequented by sound engineers and lighting designers.
www.blue-room.org.uk

National Drama - National Drama is a well-respected and influential professional organisation. It lobbies for drama teaching and theatre as a curriculum entitlement for all children and young people across the United Kingdom and provides professional support for practitioners in the sector.
www.nationaldrama.org.uk