the stage lighting guide · the stage lighting guide ... this brief guide offers a sequence of...

The Stage Lighting Guide

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A GUIDE TO LIGHTING 3Types of Light 3Floods 3Soft Spots 3Profile Spots 3Beamlights 3

CHOOSING LIGHTING POSITIONS 4Lighting from the front 4Lighting from the back and side 4Finding the compromise 5

SPECIALS 6For the Actor 6For Special Effects 6For the Scenery 6

DIVIDING THE STAGE 7Dividing by Area 7Area planning for a play 7Area planning for a musical 7Colour planning for a play 7Colour planning for a musical 8

THE DECISION PROCESS 9Example plan for a play 9Example plan for “In the Round” 9Example plan for a musical 9

DECIDING WHICH LIGHTS TO USE 10THE RIG PLAN 11LISTS 11FOCUSING 12

Focussing in comfort 12What can we adjust? 12

GLOSSARY 13

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A GUIDE TO LIGHTINGWhatever the scale of a production - amateur or professional - lighting like other design processes is based on a sequence of logicaldecisions plus a good measure of creative inspiration.This brief guide offers a sequence of step-by-step decisions to form the basis of a lighting process for the smaller scale production. Ithas been prepared by a lighting designer with experience of working on productions of all types and sizes. We hope that it will beespecially helpful to amateur groups, small touring companies and educational theatre.

Types of LightHow do we choose which type to use in each position? As lighting equipment is so robust choice is further complicated, in that inaddition to the range in today's catalogue, many earlier models are still in use. However lighting instruments group into families and it isconvenient to consider our requirements in terms of what each family offers in terms of beam size, beam shape, and beam quality.

FloodsThe beam size, shape and quality emitted by a flood is fixed: there are no adjusting knobs. The light is therefore suitable for lighting skiesand cloths. It is not selective enough for lighting actors. Strand Lighting's Coda units, a popular cyclorama flood, may be single or grouped in 3s or 4s for colour mixing. They have a reflector that is specially designed to ensure an even wash over a large area from a short throw.

Soft SpotsPrism Convex (PC) spots allow control of the beam size, and the beam may be roughly shaped by a rotatable barndoor. The quality is evenand soft-edged, with less light-spill outside the main beam than in the case of a fresnel. In addition to the PC’s, Fresnels have a very softedge. The beam angle is adjustable and its shape roughly containable by a 4-leaf rotatable barndoor. The extent of the spill outside themain beam makes them unsuitable for longer throws, particularly from the auditorium.

Profile SpotsProfile spots give precise control of the beam. An iris diaphragm (for round edges) and shutters (for hard edges) can produce shapes in allsizes. For more complex shapes, special masks can be cut. Edge quality can be adjusted from very soft to very hard by moving the lens,while a metal pattern plate called a gobo can texture the quality of the whole beam. The number in the profile's name indicates the beamangle.Whereas standard profile spots have a fixed beam angle, which is narrowed by shuttering, variable beam profiles use a pair of lenses whosedifferential movement gives a wide range of beam angles and edge qualities. The shutters are then only required for shaping. Adjustmentsare faster and more efficient use is made of the lamp's output The number in a variable profile's name indicates the range of availableangles.The new ERS type Profile Spots now provide increased light output with reduced power consumption. Often referred to as a“coolbeam” profile, they do this by using state of the art optical coating on a glass reflector, allowing the optical light to be passed forward,while the heat and infra red spectrum is allowed out of the rear.

BeamlightsMost lighting instruments produce a conical beam so that the spread widens as the throw increases. Beamlights use a parabolic reflector(and no lens) to produce a near parallel beam which is more intense than a lens spotlight of the same wattage. This is one of the moreimportant developments of the past decade. The optics are fully contained within the glass envelope of the lamp. Various Lamps providingangles of a squashed near-parallel beam are available. The intensity produces a depth-enhancing haze in the air, so intense that it iseffective even with deep colours. The basis of most classic rock lighting effects.


CHOOSINGLIGHTINGPOSITIONSLighting from the frontConsider the effect of a light startingas a vertical downlight on an actor thenmoving in a frontal plane until its beambecomes horizontal and then carries onto light from below. How visible will bethe actor's face, particularly eyes andteeth? To what extent will face andbody be modelled or flattened? Whatarea of stage will be selected and whatwill be the size and direction ofshadows cast on floor and scenery?

A vertical beam is the most selectivelight possible. The lit area of stage,and the shadow cast upon it, need be nowider than the widest part of the actor.However, the actor's eyes will be blackpools and a highlighted nose will shadethe mouth.

If the light comes from a little forwardof the actor, it will start to reach theeyes and mouth (provided that shekeeps her chin up and is not defeatedby a hat brim!). However, the lit area,and shadow cast, starts to extend

upstage from the actor - i.e. the light isslightly less selective.

As the lighting comes increasingly fromthe front, the actor's eyes and teethreceive more light. But the area litextends further and further upstage,reducing the selectivity and increasingthe likelihood of the actor's shadowhitting the scenery

As the light becomes more and morefrontal, the actor's features becomeflattened (and so also does three-dimensional scenery). The lit area andthe actor's shadows increase until,when the light is horizontal, there is alit corridor for the entire depth of thestage, and the actor shadows becomeactor length.

Light from below projects an actorshadow that looms above the actorrising and falling as she moves towardsand away from the light source. Whenthis is the only lighting angle, theeffect on the face is not at all natural.But a little from below, usually justreflected light can help to soften theharshness of light from above.

Lighting from the backand sideNow consider a light from behind.Then a light or lights from a series ofside angles (i.e. lights at right anglesto those considered above). Once againthe criteria is visibility, modelling,selectivity and shadows.

A light source behind the actor doesnot illuminate the face, but it helps togive depth to the stage by separatingthe action from the scenery throughcreating a haze and highlighting headand shoulders. The shadow of theactor is cast forward, helping theselection of areas. Since the light doesnot fall on the face, strong colours canbe used.


If the light comes from a little to oneside of the actor it will start to reachthe eyes and mouth on that side. Thearea lit, and the shadows cast, willextend along the stage floor on theother side.

Add a second light source from theother side, and both sides of the facewill receive light. However, there isnow a second shadow and the selectedarea of stage floor extends to bothsides of the actor.

As the side lighting comes from anincreasingly lower angle, the shadowswill lengthen to both sides of the actorand a larger corridor will be selectedacross the stage. As the light hits the

face from a lower angle, it will lightmore into the eyes and teeth, althoughthere will still be a tendency towards acentral dark line where the beams meetdown the centre of the face.

As the angle lowers, sidelight has anincreasingly modelling effect on theactor's face and body. This isparticularly important in dance. Whenthe light becomes horizontal there willbe a lighting corridor across the wholestage. By focusing just clear of thefloor, it is possible to lose shadows intothe wings, and the light will only beapparent when an actor stands in it.

Finding the compromiseWe normally seek to light an actor formaximum visibility and maximummodelling, with minimum shadow.Additionally in many productions, weneed to select as tight an area aspossible. Which combination of anglesoffers the optimum compromise?

The basic compromise that has longbeen the standard approach is a pair ofbeams crossing on to the actor (one foreach side of the face) from positionsthat are both forward and to the sideof the actor. The suggested angle isoften around 45 degrees in bothdirections - i.e. midway between

vertical and horizontal and midwaybetween front and side. However torestrict the shadows cast and to give abetter 'join', the lights are oftenpositioned closer to the vertical and tothe centre.

A backlight added to the basic crossedpair brings depth to the scene andgenerally enhances the 'look' of theactor. The backlight can be used forstrong atmospheric colour if required,while the crossed pair maintain a morenatural tint on the actor's skin tones.Note: The actor is now It by threebeams with a 120° separation betweenthem.

The problem with 'crossed pair' lighting(with or without a backlight) is theextent of the spread of light on floorand scenery beyond the area where theactor's head is lit (remember that headis usually about five feet above thefloor). Although a single beam can beflat it can also be quite tight.


Adding a backlight can enhance thisflatness quite considerably - and theselectivity is still a tightly controlledupstage/downstage corridor withoutside spillage.

For modelling, sidelights can be addedand, although they will spread the litarea, they can be at quite steep anglessince they do not need to make a majorcontribution to visibility. Note: Fourbeams now light the actor with a 90° separation between them.

SPECIALSThe major proportion of a stage lighting rig is focused to form a palette of areas and colours whose various combinations will provide thedesired fluidity of selectivity and atmosphere. However there are certain lights whose function is so 'special' that they cannot make asignificant contribution when mixing the basic palette.

For the ActorSpecials usually consist of spotlights set so tightly that the spaces they light cannot be considered as areas. They are often for momentswhen an actor has to be picked' out (perhaps only head and shoulders) on an otherwise blacked-out stage. They need to be listed in apriority order for close scrutiny and reduction to essentials.

For Special EffectsThere may be a request for equipment to produce clouds, flames, water, lightning, etc. When listing it is always prudent to remember thatsuch effects can draw attention away from the actor rather than positively support a performance. And if the effect is essential, then theeffect of light reflected from fire or water is often more telling than a pictorial representation of the actual fire or water

For the SceneryThe proportion of the rig focused on the scenery will be very small. With the exception of skies and back or front cloths, scenery normallygets sufficient general wash from the reflected light bouncing off the stage floor from the lights that have been set for the actors.Indeed, as discussed in the following pages, many of the basic problems of lighting design arise from difficulties in stopping actor lighthitting directly on the scenery Successful lighting of scenery depends on augmenting the diffuse reflected general light by selectivehighlighting of chosen scenic elements, or parts of these elements. This can vary from bold gashes to soft emphasis. Again, to be listedand reduced to essentials after a debate based on priorities and available resources.


DIVIDING THE STAGEDividing by AreaOnce decisions have been made about the kind of contributionthat we expect lighting to make to the production that we areplanning - and these contributions have been put into some sortof order of priority - we need to break down the stage area intothe segments over which we require independent selectivecontrol. The required breakdown may be symmetrical, in whichcase the stage plan will be divided into something that resemblesa series of areas of different sizes corresponding to the placingof the action. Of course it could well be that there is no needfor division into what it is useful to call production areas: all thestage may be in use all the time. In this case a simple divisioninto centre and sides will allow balancing for maximum'enhancement' of the look of the scene.Note: Adjoining areas overlap - both side to side and back tofront. And remember to remember that these are areas wherean actor's head is to be lit - they ore unlikely to be the some asthe light patterns on the floor

Area planning for a playIn this naturalistic play -possibly but not necessarily in a box set-the areas are determined to a considerable extent by thepositions of furniture and doors. And the lighting is expectedto make some logic in terms of practical light fittings (tablelamps, wall brackets, etc.) and the natural sunshine and moonlightcoming through windows (including those in the audience's'fourth wall'). In this particular example, we have a play whereit is desirable to focus attention at various times on the sofa,the armchair, the table (with that essential tool of moderndrama, a telephone) and the doors. These doors aretremendously important in any drama: some of the keyappearances and speeches are made there. But for a longintimate scene on the sofa, it is useful to concentrate on thatsofa and loose peripheral areas like the doors. Consider theseven areas shown here in terms of possible combinations: thearea palette gives the director a wide range of selectivity ofaudience vision - whether a subconscious fluidity (slow cues thatare not obvious) or an area selection obviously linked to theswitching of the practical lamps

Area planning for a musicalMusicals tend to have many scenes and many selective andatmospheric light changes within these scenes. Therefore,unless there are many - very many - lights available, thebreakdown into areas has to be very general. In this examplethe breakdown is symmetrical because, as in so many musicalproductions, the settings consist of a symmetrical series ofwings leading to a backcloth, possibly a skycloth. With theaddition of cloths and scenic pieces, the method of staging givesa flexible masked acting area with the possibility of sufficientopen space for dancing and lots of entrances for a large chorusto get on and off quickly In most musicals the big moments arestaged in the downstage areas: to help both musical balance andthe 'putting across' of numbers to the audience. For the samereasons, much of the essential action takes place centre stage.The most common selective lighting cue is to 'concentratecentre', usually downstage centre, by 'losing the edges'. Thissuggests a minimum of three areas across the stage - certainlyat the front of the stage, and probably also midstage. However,it is often quite practical to consider the whole width of the rearof the stage as one area. This provides a seven areacombination that offers an area palette giving the directorconsiderable selectivity with the possibility of progressivetightening from back to front and from sides to middle.

Colour planning for a playIn a naturalistic play, colour is often used to create a fluidatmosphere that can shift from warm cheerfulness to coolsadness. If an area is lit with some lights in warm tones andsome in cools, the dimmers of the control board can be used toachieve a whole series of options from an extreme of the warmcolour alone, through the neutrality of both together, to theother extreme of cool colour alone. Which (if any) of the areasneed to have this kind of 'double cover' of colour tones? In thisexample, discussion with the director has established that such acolour palette seems necessary around the central areas and thedesk, whereas the upstage corners and downstage right canmanage on a warm tint only - although perhaps one that is a littlecloser to a compromise neutral than the warms in the mixableareas. In such a naturalistic production the actual colour tintschosen are likely to be quite subtle.


Colour planning for a musicalThe dialogue scenes of a musical require the subtle colour tonesthat are appropriate for a naturalistic play However, the musicalnumbers, particularly when solo singers can be given isolatingvisibility from tightly focused follow spots, usually call forstrongly atmospheric colouring. And many dance sequences,where the body is relatively more expressive than the face,

respond well to positive use of quite strong colour This exampleshows a much used technique where the colour is applied inrather broader washes than the areas selected for scenelocation. The front half of the stage is divided into three areas,each lit from above in rather saturated colours: a hot and coldrather than a warm and cool. The rear half is treated as onearea, also with a hot and cold from above. From the side comesfurther washes, probably in slightly less saturated hues. Thesemay divide the stage into bands: in this case an upstage band anda downstage band, possibly splitting the stage into left and rightbut just as likely covering the full width. With relatively neutralcolour from the front, saturated colours from above andintermediate colours from the side, we have a colour palette thatoffers considerable scope.


THE DECISION PROCESSSo how does one decide where to put the spotlights? On manystages and in many auditoria there is not much choice: but, tomake the best use of the positions available, it is necessary tostart from an ideal and compromise that ideal to fit reality. ByWHERE, we mean where to put the light and where to point it.Traditional advice involves a lot of crossing of light beams -partly to help model/sculpture the actor by introducing apartially side-light angle and partly because lighting diagonallyacross a stage provides a bigger spread of light from each lamp:an important bonus when equipment is in short supply. Crossingthe beams opens out the area lit but can cast excessive shadowson side wall or masking. And so, with spotlights becomingincreasingly versatile as to beam width, there is every reason toconsider using the traditionally discredited method of lightingthe actor with light coming straight in from the front. Of courseif this is the only light, yes it will be flat. (And if the availablepositions are so low that an actor shadow will be thrown on tothe sky, then better to come diagonally - priorities again!) Butwith the addition of some backlight (even if it is nearly vertical)and some sidelight, the front-lit actors will come alive and theareas/ shadows brought more under control. There need not beprecise side lighting for every area: it can often be quite generalsince it is frequently more important in the big wide areas thanin smaller tighter areas (more important, that is, in priorityterms!).In the examples shown here, the traditional crossing method hasbeen used for the play, while the actors in the musical are lit'flat frontal'. But it could be vice versa. Whichever way, the nextstage in the planning is to establish where the lights go andwhere they point.

Example plan for a play

For each area of our play we need two lights. One for each sideof the actors' faces. When an area requires a full colour controlof cool and warm, the number will double to four spots - acrossed pair in warm and a pair in cool. A spot bar immediatelybehind the proscenium arch will give a suitable angle for lightingthe upstage areas, but for the downstage areas a position in theauditorium is necessary Red and blue have been used to indicatewarm and cool filters in the spots. Green indicates more neutralwashes that have been added from back and sides. Not enoughequipment? Well, do we really need all these areas? And so manyof them with both warm and cool? (Back to priorities?) Or rather

than a pair, we could use a single straight in - but if so, we mustmake it really straight in because a single crossing beam does notdo much for the other side of the face!

Example plan for “In the Round”

For staging in the round, light needs to come from all sides. Andit should be evenly balanced to avoid favouring one segment ofaudience to an extent that is not really permissible in a stagingform so democratic as theatre-in-the-round. To avoid hittinginto audience eyes, light has to come from both within the actingarea and from outside it. Angles can be closer to the verticalthan in other forms of staging because the audience is closer tothe actors and thus visibility is 'easier'.

Example plan for a musical

In this musical the actors' visibility light is provided by spots ina neutral colour hitting straight in. The front areas are coveredfrom the auditorium, the midstage areas from a bar just insidethe proscenium, and the upstage areas from a midstage bar Ifthe stage is very wide, two or more lamps may be required foreach area as indicated. Strong colour comes from near verticalbacklights and medium colour from the wings (on stands, boomsor ladder-frames to be discussed under 'rigging).Note: For clarity these plans only include actor lights. The playwould require light outside the window and on the door backings,while the musical is likely to need a colour mix for the backclothand possibly specials for elements of scener


DECIDING WHICH LIGHTS TOUSEDeciding which instrument to use obviously depends to a largeextent on what is available - meaning another exercise in listingpriorities. For 'foh' (front of house) throws of any distance inthe auditorium, profiles are essential, both to avoid undesirablelighting up of the auditorium from scatter light, and to allowsufficiently precise control of the beam to prevent spillage on tothe proscenium. However in a small hall there is a lot of merit inconsidering fresnels or PCs (well barndoored) at close rangewhen a lot of spread is possible from a few lamps. For onstageuse, Fresnels and PCs come into their own with fast-to-set softedges - profiles are the most versatile instruments but theyinevitably take longer to focus. For backlight, fresnels andbeamlights are favourite, while floods are to be thought of onlyfor wide expanses of scenery. (Use for actor light only insituations of extreme desperation). For theatre-in-the-round,barndoored fresnels give the required smoothness and spread.Existing installations in most theatres and halls are likely to bebased on fresnels and profiles: anyone buying new equipmentshould look seriously at including a goodly proportion of the newgeneration PCs giving smooth soft-edge beams without strayscatter light and at the versatility of the variable beam profiles.

This plan shows instruments being allocated to our play in a veryorthodox way: profiles for the front-of-house and fresnels foronstage. If a couple of PCs were available, they would be auseful alternative on the ends of the stage spot bar: this is aposition where any scatter light shows up badly on the side wallsof the set. Whether 500 or 1000W units are required willdepend mainly on length of throw, perhaps with the changeoveraround 6 to 8 metres. However, it is important always toremember that the actual level of light intensity is not soimportant as the BALANCE.

Fresnels have been allocated everywhere because they have agood smooth spread (profile edges can be very difficult in smalltheatres in the round). Every spot must have a barndoor tocontain spill from the audience eyes. Each become a pair ofspots since this is the only way that it is possible to light fully tothe sides of the acting area.Too many-spots? Then perhaps just one cover in a neutral shade(thereby halving the number on the plan) and utilising a couple ofpairs of straight downlighters to add colour toning in warm orcool.

The actor face lights are profiles from the front and fresnelsonstage, with the second bar being less powerful units - facelight is rarely important upstage in a musical. The backlights arefresnels, although parcans would be nice if available. For thesidelighting, profiles have been used downstage to contain thelight in a tight corridor across the front - often advisable whenfront cloths or running tabs are in use. Midstage sidelighting usefresnels for a good spread, while the optional upstage sidelightagain uses profiles to keep the light clear of the skycloth.


THE RIG PLANTHE PLAN is the kernel of any lighting design. It shows, atminimum:1. The POSITION of each light.2. The TYPE of light in each position.3. Any ACCESSORIES, such as barndoors or gobo, required by

any particular light.4. The DIMMER that will control each light.

The plan should be drawn to scale (1" to I ' or 1:25). This helpsaccurate indication of light positions. And if scale symbols areused for these lights, there is a check on space problems: if itcan be drawn on the plan, there will be room for it on the stage.Any shapes may be used to indicate lights, but plans are moreeasily read if the symbol resembles the outline shape of thelight. Either way, the plan should certainly include a key showingthe type of lighting instrument represented by each symbol.Colour and dimmer are indicated by number: the usual conventionis to write the colour number inside the symbol and the dimmernumber alongside the symbol.Lights fixed to horizontal bars are easy to show in plan: the barcan be drawn in the position that it will occupy over the stageand its height indicated by a note (such as + 14') written at theend of the bar. Lights fixed to vertical bars, or stacked on aseries of brackets, are more difficult to draw - they must beindicated diagrammatically FOH lights in the auditorium areusually drawn much closer to the stage than their scaled realdistance which would make the plan inconveniently large. Theeasiest method is to work on tracing paper over a ground plan ofthe scenery and stage.

A good procedure is:1. Establish all lighting positions with Xs2. Convert these Xs to symbols of available (and/or acquirable)

lighting instrument types, drawing them pointing in theapproximate direction of proposed light travel.

3. Write colour numbers inside symbols.4. Add dimmer numbers alongside symbols.5. Trace through key features of the set and stage - it is

usually possible to trace through (in spaces clear of lightingdrawing) enough to relate the positions of lights to thegeography of the setting and stage.

This will bring the plan to a point where it can be used to prepareand rig the equipment. The lighting designer's own copy will growmany extra markings to indicate precisely where the lights areto be pointed - markings so detailed that they would only confuseif included on all copies of the plan.

LISTSFrom the plan, lists are prepared of the required number of:1. Types Of Light2. Lengths Of Cable3. Accessories4. Colour Filters5. Section Drawings

Will there be borders to mask the lights (and other things)hanging above the stage? If so, draw a section to check that allthe light beams will be able to reach all desired parts of theactors and the scenery. Usually (but not always) the heights ofthe borders and lighting bars can be adjusted. Only a sectionwill determine what these relative heights should be, and only asection will determine how effective the masking arrangementswill be for an audience eye in the front row.


FOCUSINGFocusing is probably the most important part of the wholelighting operation. Not even the most sophisticated marvel of amicroprocessor control desk can fill in that dark spot where thelights have not been properly overlapped. Nor can a hard edgebe softened or a disturbing spill on to a border be shuttered off.Focusing involves tricky ladder work so that there is everyincentive to get it right first time - although, inevitably, it willbe necessary to get at the odd spotlight between rehearsals fora little fine adjustment.

Focussing in comfortIf you stand with your back to the light that you are focusing,(I) You will avoid being blinded (2) You will be able to see whatthe actor's light is doing to the scenery

No clear shadow ofhead, thereforehead is not lit.

Clear shadow ofhead, thereforehead is lit

If the lightingdesigner is shorterthan the actor,make an allowance -check by raisinghand

What can we adjust?ON ALL LIGHTS

Left/Right & Up/DownON SOFT SPOTS

Bigger/Smallerwith optional Barndoor Rough shaping (& control ofspill)

ON PROFILE SPOTSRound size by optional IrisShaped size by ShuttersTexture by optional GoboBeam edge quality by Lens and on Variable Beam ProfileSpotsSize and edge quality by differential movement of twoLensesShape by Shutters

The most difficult types of light are the basic Profile Spotssince there is an interaction between shutters (or iris) and lensmovement. Although adjusting the lens is principally a means ofmaking the edge of the beam harder or softer, it will also changethe size. Therefore it is usually necessary to adjust shuttersand lens alternately to get the desired combination of size andedge quality

Most profiles have an adjustment whereby the light can beadjusted so that it is either smooth across the whole spread ofthe beam, or 'peaked' to be brighter in the middle with theamount of light falling off towards the edge. For most purposesit is easier to light with an even brightness across the beam andso it is recommended that anyone beginning to work with lightshould use an even beam until through experience they discover aneed for a 'peaky' beam.SOFT SPOT

VARIABLE ANGLE PROFILE SPOT

FIXED ANGLE PROFILE SPOT


GLOSSARYBacklightLight coming from behind

scenery or actors to sculpt andseparate them from theirbackground.

Bar Horizontal metal tube ofscaffolding diameter for hanginglights (pipe in America)

Barndoor Four-shutterrotatable device which slides intothe front runners of fresnel and PCfocus spots to shape the beam andreduce stray scatter light.

Battens Lengths of overhead lightingfloods arranged in 3 or 4 circuitsfor colour mixing.

Beam angle Angle of the cone oflight produced by a spotlight.

Beamlight Lensless spotlightwith parabolic reflector givingintense parallel beam

Board Contraction of switchboard ordimmerboard. The central controlpoint for the stage lighting.

Boom Vertical pole, usually ofscaffolding diameter, for mountingspotlights.

Boom arm Bracket for fixingspotlights to a boom.

Build An increase in light intensity.Channel A control circuit, identified by

number, from the 'board' to a light.Channel access The method (levers,

pushes, keyboard, etc) in a memorysystem by which individual channelsare brought under operator control.

Check Decrease in light intensity.Colour call A listing of all the

colour filters required in eachlighting instrument.

Colour temperature A methodof measuring (in Kelvin units) thespectral content of 'white' light.

Control Surface Any device such aslever, push, wheel, rocker, mouse,pen, cursor, etc, used as aninterface between an operator'sfingers and a processing systemwhich activates dimmers or motorscontrolling lighting instruments.

Cross-fade Lighting changewhere some of the channelsincrease in intensity while otherchannels decrease.

Cue The signal that initiates achange of any kind. Lighting cue is achange involving light intensityalterations.

Cyclorama Plain cloth extendingaround and above the stage to give afeeling of infinite space. Term isoften rather loosely used for anyblue skycloth, either straight orwith a limited curve at the ends.

Dead (1) The plotted height of apiece of suspended scenery or barof lights. (2) Discarded items ofscenery.

Dichroic Colour filters which work byreflecting unwanted parts of thespectrum rather than absorbingthem in the manner of traditionalfilters.

Diffuser A filter, often called a frost,which softens a light beam,particularly its edge.

Dimmer Device which controls theamount of electricity passed to alight and therefore the intensity ofthat light's brightness.

Directional diffuser A filterwhich not only softens the beam butspreads it along a chosen axis. Alsoknown as a silk

Director Has the ultimateresponsibility for the interpretationof the script through control of theactors and supporting productionteam.

Discharge lamps Special high poweredlight sources whose use is normallyrestricted to follow spots andprojection because of difficulties inremote dimming by electrical means.includes C.S.I., C.I.D. and H.M.1lamps.

Downstage The part of thestage nearest to the audience.

Ellipsoidal Strictly a type ofreflector used in many profile spotsbut extended in North America tocover all profile spots.

Flood Simple instrument giving fixedspread of light.

Flys Area above the stage intowhich scenery can be lifted out ofsight of the audience.

Focusing Strictly speaking, theadjustment of lights to give a

clearly defined image; but usuallyused to cover the whole process ofadjusting the direction and beam ofspotlights in which the desiredimage may be anything but clearlydefined.

FOH All instruments which are'front of house', i.e. on the audienceside of the proscenium.

Follow spot Spotlight with which anoperator follows actors around thestage.

Fresnel spot Spotlight with softedges due to fresnel lens which hasa stepped moulding on the front anda textured surface on the back.

Frost A diffuser filter used tosoften a light beam.

FUF Full-up-finish. An increase tobright light over the last couple ofbars of a musical number.

Gate The optical centre of a profilespot where the shutters arepositioned and where an iris or gobocan be inserted.

GAUZO Fabric which becomestransparent or solid underappropriate lighting conditions.

Gobo A mask placed in the gate of aprofile spotlight for simple outlineprojection. Also used, withsoftened focus, to texture thebeam.

Groundrow A low piece ofscenery standing on the stage floor.Also lengths of lighting placed onthe stage floor.

Group A subdivision, temporary orpermanent, of the channels in acontrol system.

Hook clamp A clamp for fixing aninstrument to a horizontal bar,usually of scaffolding diameter.

Houselights The decorativelighting in the auditorium.

Instrument A stage lighting unit,such as a spotlight or flood. AnAmerican term coming intoincreasing international use.

Iris An adjustable circulardiaphragm to alter the gate size in aprofile spot. Also the muscle-operated diaphragm in the humaneye which adjusts the eye's


aperture to changing lightintensities.

Kilowatt see wattageLadder Framework in the shape of a

ladder for hanging side lighting.Lamps The light source within an

instrument, but sometimes used asan alternative to the wordinstrument.

Lantern A lighting unit designed oradapted for stage use. A traditionalword now being overtaken by'instrument'.

Linear flood A flood using a longthin double-ended halogen lamp,allowing the reflector to bedesigned for an increased beamspread.

Load The lights controlled by anindividual dimmer and limited by therating of that dimmer.

Master A lever or push whichoverrides (or 'masters') a completepreset, or group within a preset orselected memory.

Memory Lighting control systemswhere channel intensities for eachcue are filed automatically in anelectronic store.

Multiplexing Passing controlinstructions, particularly to dimmersor remotely focusable lights, bysending all information in digitalformat along a single pair ofscreened wires.

PanHorizontal (left/right) movement ofan instrument.

Parcan The simple instrument whichholds a par Imp and therefore doesnot require any optical system oflenses or reflectors.

Par Imp A sealed beam lamp with thefilament contained within the sameglass envelope as an optical systemproducing a near parallel beam.

Patching A sort of central 'telephoneexchange' where channels can beconnected to dimmers and/ordimmers connected to socketoutlets.

P.C. [Plano convex] lens A lenswith one flat surface and onecurved surface. This 'PC' lens andthe fresnel lens are the alternativesnormally used in stage spotlights.

Pipe endsSpotlights on the ends oflighting bars, crosslighting to modeldancer's bodies.

Playback The part of amemory system where memorisedlighting states are recalled tocontrol the light on stage via masterlevers or pushes.

Practical Light fitting which isnot merely decorative but is wiredto light up.

Preset Anything which is positioned inadvance of its being required --suchas props placed on the stage beforethe performance. A control systemwhere each channel has more thanone lever to allow intensity levels tobe set (i.e. preset) in advance of acue.

Profile Spot A spotlight whichprojects the outline (i.e. the profile)of any chosen shape and with anydesired degree ofhardness/softness.

Profiled Cue Lighting changewhere the rates of increasing anddecreasing intensities accelerate ordecelerate during the progress ofthe change.

Rating The maximum and minimumpower in kilowatts that can becontrolled by a circuit or dimmerchannel.

Record Plotting a cue state by filing itin the electronic data storage of amemory board.

Resistance dimmerAn older mechanicalform of dimmer which reduces theflow of electricity to a light byprogressively converting the surplusinto heat.

Rigger's control A remote portablehand-held control unit which allowschannels or groups to be switchedfrom the stage for focusing whenthe control room is unmanned.

Scatter Low intensity light castoutside the main beam of aninstrument.

Scrollers Colour changer where a roll offilters are taped together andpositioned by a very fast motoractivated by digital signals from acontrol system which includes amemory facility.

Shin Busters Low level lights atstage floor level, used mainly fordance.

Sightlines Lines drawn on planand section to indicate limits ofaudience vision from extreme seats,including side seats, front and backrows, and seats in galleries.

Silks Diffusion filters whichstretch the light in a chosendirection.

Spigot An adapter screwed to thehanging bolt of an instrument toenable it to be mounted on a floorstand.

Spill stray or scatter light outsidethe main beam.

SpotlightAn instrument giving controlof the angle of the emerging lightbeam and therefore of the size ofarea lit.

Strobe Device giving a fast series ofvery short light flashes under whichaction appears to be frozen.

Theatre-in-the-Round A form ofstaging where the audience totallyencircle the acting area.

Throw Distance between a light andthe actor or object being lit.

Thrust Form of stage which projectsinto the auditorium so that theaudience are seated on at least twosides.

TiltVertical (up/down) movement of aninstrument.

Tungsten lamps Older type of lamps(the stage types are high wattageversions of standard domesticlamps) whose tungsten filamentsgradually lose the brightness oftheir light output.

Tungsten halogen lamps Newer lamps(now virtually standard inprofessional theatre) which maintaintheir initial brightness of lightoutput throughout life.

Upstage The part of the stagefurthest from the audience.

UV Ultra violet light (from whichharmful radiation have been filteredout) used to light specially treatedmaterials which fluoresce in anotherwise blackened stage.

Variable bean profile Profilespotlight using a type of zoom (q.v.)arrangement where the differentialmovement of two lens allows widevariations in both beam size andquality.


Wattage The power of consumption of alamp, or the maximum availablepower from a dimmer. A kilowatt is1,000 watts.

Ways The number of channels in acontrol system.

Zoom A differential movement oftwo lenses in an optical system. In asimple zoom, the lenses are movedindependently, but in more complexforms a single movement alters thesize of the beam while the image

remains in constant focus. Used inadvanced profile spots and sceneprojectors.

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