Lighting
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Gordon Nimmo-Smith
This is an introduction to stage lighting, covering the details of the different types of equipment available, the lighting design process and a discussion of the different venues within student theatre in Oxford from a lighting designers point of view. However, ultimately lighting design is something that can only be mastered through experience of playing with lights, seeing how they work and seeing other people’s designs in action. Thus, this guide is intended to act as a reference point rather than a one-stop shop for everything you need to know to lighting design for theatre.
The Equipment
Firstly, before going into lighting design, you need to know something about the different bits of equipment that you will encounter.
Lantern Types
All theatrical lanterns follow the same basic principles of design. All consist of a lantern mounted in a housing with an aperture at the front to let the light out, and reflector behind the lamp to direct the light forwards. Most come with a yoke and clamp to hang them from bars in a lighting grid and colour runners on the front so that they may be coloured up as desired. There is great variation between manufaturers however there are basic categories into which most lanterns fall.
Profile Lanterns
Profile Lanterns consist of a lamp housing at the rear, and then a barrel on the front containing one or two independent plane convex lenses. Moving these lenses relative to the lamp causes the size and sharpness (”focus”) of the light beam to be altered. Profiles range from 300W right up 2000W, athough with the advent of new designs the power rating can be misleading. They are available in two main categories: fixed beam and zoom. Fixed beam lanterns have one lens, so that only the focus of the beam may be changed from sharp-edged (in-focus) to soft-edged (out-of-focus) but the size of the spot cannot be altered. Zoom profiles have two independant lenses, meaning that the size of the beam as well as it’s focus may be altered. This makes them a lot more flexible as you then do not need to work out the beam angle required, or for situations where you are unable to work out the angle in advance of the get-in. Most profiles will also have a set of four shutters which can be used to shape the light beam, for example to a square, or to remove spill from the light. Iris’ can be inserted in the optic gates for profiles, in between the lamp housing and the lenses, to reduce the beam size further, at the expense of the output power.
Beam Angle - This is the angle between the normal (A straight line from the centre of the lantern going forwards) and the edge of the light beam as it leaves the lantern. A small beam angle gives a narrow spot, a large beam able gives a wider spot. Profiles tend to range from around 5� for a tight special or a followspot to about 50� at their widest.
Profiles can be used as wash lights, providing the general cover lighting for the stage. They will normally be hung front-of-house i.e.. above the audience to provide frontlight for the stage. As the light beam can be focused and shuttered they are also used as “specials”, providing a light for a specific point or person on the stage (although whether or not the performer will choose to stand in their special is a matter for the Gods quite frankly). Lastly gobo’s, which are metal discs with a pattern cut into them, may be inserted in the optic gates and then focused by the lantern to project patterns onto stage.
Fresnel and Plane Convex (PC) Lanterns
These lanterns consist of a lamp in a lamp housing, with a lens mounted on the front. They are focused by moving the lamp and lens in relation to each other, normally the lamp mounting slides back and forth within the lamp housing behind the lens. Fresnel lanterns contain a fresnel lens with concentric ridges running around it, whereas a PC lens is a plane convex lens similar to those in profiles, but with a heavy frosting on the surface. Both fresnel lenses and PC lenses give a sort edged beam. Barndoors can be fitted onto the front of the lanterns to shape the beam and reduce spill.
As these lanterns only have one lens, they cannot be hard focused, and are used as washlights to provide general lighting for the stage, either from the front, sides or above the stage depending on the venue. They often have a very wide beam angle range (PAT743’s will open up to 80�)
Parcans
Parcans consist of a sealed lamp and lens with fixed beam angle combined into one, mounted in a metal shell. The lamps can be bought in a variety of beam angles ranging from narrow to extra wide depending on what is required. They are available in a number of sizes ranging from a Par64 (8″ diameter) to a Par16 (2″ diameter). Barndoors can also be fitted. The smaller Pars such as Par16s tend to use low voltage lamps eg. 12V, so a transformer must be fitted to these before plugging them into the supply. Parcans were developed for rock and roll lighting, being quick and simple to rig for a touring show and (practically) indestructible.
Par64’s usually contain a 1KW lamp, and are be best used for saturating the stage with colour - being developed for rock and roll lighting they are rather good at this. Par16s, also known as Birdies, due to their small size, are often found fitted to set pieces. For example, a production of La Boheme at the Oxford Playhouse used two inside a stove to provide a flame effect.
Floodlights
Floodlights are designed to flood areas with light, and as such consist merely of a long thin lamp and a reflector. The reflector can either be symmetrical, with a uniform curve behind the lamp, or assymetrical. The assymetric reflector causes the floodlight to throw more light out of one side than the other. Floods are availible as either single units, as battens (usually 4, 6 or 8 units) of floods mounted either in a line or as flood cells consisting of 4 units mounted in a square. Groundrows are effectively a flood batten which is designed to sit on the floor rather than being hung from a lighting grid.
Due to their crudeness, floodlights have a limited use in conventional theatre as you have no control over the beam at all. Their one predominant use is to light cyclorama cloths across the back of the stage. Typically, assymetric floods will be hung at the top of the cloth, the bias in the direction the light is thrown means that the cloth will be lit and no light goes upwards towards the ceiling. For a larger cyc, you may also place a groundrow across the bottom as well, to ensure even coverage of colour. Otherwise floods can also be used as houselights or as audience blinders.
Intelligent/Moving Lights
With the so-called generic theatre lanterns covered thus far, once they are rigged all their attributes (direction, colour, size etc.) with the exception of brightness cannnot be altered. Intelligent lights on the other hand may be controlled by the lighting designer throughout the show, their colour, direction, size, anything can be altered. To use, they require a data feed (DMX512) as well as power, and a control desk capable of controlling the various attributes. Common types are moving heads and moving mirror/scanners.
These lights require a great deal more skill and experience to operate than parcans, fresnels etc. firstly because they are a lot more complicated to set-up, and secondly because the realm of possibilities that they open up means that it can be easier to go wrong. Many’s the time a show has been spoilt by a completely gratuitous moving light effect, just “because they could”. However, used carefully they can enhance a show many times. Most commonly found in general theatrical use are washlights such as the VL5B or Mac600. These provide stage cover but their colour can be altered, either using a colour wheel or by complete CMY (Cyan-Magenta-Yellow) colour mixing. This can greatly reduce the number of fixtures required as well as providing a great deal more flexibility to the design. Intelligent profiles and scanners are used more for effect, searchlights and the such.
Other Types of Lantern
Apart from the above types of lantern, there are also many others which you may encounter as a lighting designer, but I shall limit myself to practicals and followspots. Practical is a term for a working light which forms part of the set for a show, and is powered and controlled by the lighting designer. Such things may include desk lights, festoons on the set or a light inside a computer monitor. Followspots are a narrow angled profile, typically 5 to 10�, which is mounted on a tripod and then moved by an operator rather than having a fixed focus. They can then be used to pick out a particular performer or piece of action on the stage. They are most commonly found in musicals, where the lighting is often a lot more stylised.
Lighting Control
Although most lanterns can be plugged directly into the mains, you would not have much control over their intensity, and also most buildings cannot handle the amount of current pulled by stage lighting, typically an average of 4.5A per light (for a 1KW light). Stage lights are powered by dimmers, which in turn must be controlled by some sort of lighting desk. This allows you to set the levels of each light, or channel, to build up each individual state.
Dimmers
Each channel of a dimmer consists of a rheostat which varies the current being supplied to a light that is plugged into it. They can be either analogue or digital, with the control signal from the lighting desk setting the level of each channel. Care must be taken not to overload dimmer channels when planning a lighting rig. Most dimmers can only handle a load of 10A, which equates to just over 2KW of lights. Thus, when planning your lighting design you have to consider the number and power of the dimmers available to you and make sure you stay within their working limits.
