Stage Lighting Guide

1/11/2015 Stage Lighting Guide

http://www.stagelightingguide.co.uk/ 1/15

StageLightingGuide

A GUIDE TO LIGHTING

TYPES OF LIGHT Floods Soft Spots Profile Spots Beamlights

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

SPECIALS For the Actor For Special Effects For the Scenery

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

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

DECIDING WHICH LIGHTS TO USE

THE RIG PLAN

LISTS

FOCUSING Focussing in comfort What can we adjust?

GLOSSARY

A GUIDE TO LIGHTING

Whatever the scale of a production - amateur or professional - lighting like other design processes is based on asequence of logical decisions 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 smallerscale production. It has been prepared by a lighting designer with experience of working on productions of all typesand sizes. We hope that it will be especially helpful to amateur groups, small touring companies and educational



theatre.

Types of Light

How do we choose which type to use in each position? As lighting equipment is so robust choice is furthercomplicated, in that in addition to the range in today's catalogue, many earlier models are still in use. Howeverlighting instruments group into families and it is convenient to consider our requirements in terms of what eachfamily offers in terms of beam size, beam shape, and beam quality.

Floods

The beam size, shape and quality emitted by a flood is fixed: there are no adjusting knobs. The light is thereforesuitable for lighting skiesand cloths. It is not selective enough for lighting actors. Strand Lightings Coda units maybe single or grouped in 3s or 4s for colour mixing. They have areflector that is specially designed to ensure an evenwash over a large area from a short throw

Soft Spots

Prism 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. Inaddition to the PC‛s, Fresnels have a very softedge. The beam angle is adjustable and its shape roughly containableby a 4-leaf rotatable barndoor. The extent of the spill outside themain beam makes them unsuitable for longerthrows, particularly from the auditorium.

Profile Spots

Profile spots give precise control of the beam. An iris diaphragm (for round edges) and shutters (for hard edges) canproduce shapes in allsizes. For more complex shapes, special masks can be cut. Edge quality can be adjusted fromvery soft to very hard by moving the lens,while a metal pattern plate called a gobo can texture the quality of thewhole 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 usea pair of lenses whosedifferential movement gives a wide range of beam angles and edge qualities. The shutters arethen only required for shaping. Adjustmentsare faster and more efficient use is made of the lamp's output Thenumber in a variable profile's name indicates the range of available angles. The SL New Generation Profile Spots, from Strand Lighting, now provide increased light output with reduced powerconsumption. Often referred to as a “coolbeam” profile, they do this by using state of the art optical coating on aglass reflector, allowing the optical light to be passed forward,while the heat and infra red spectrum is allowed outof the rear.

Beamlights

Most lighting instruments produce a conical beam so that the spread widens as the throw increases. Beamlights use aparabolic reflector(and no lens) to produce a near parallel beam which is more intense than a lens spotlight of thesame wattage. This is one of the more important developments of the past decade. The optics are fully containedwithin the glass envelope of the lamp. Various Lamps providing angles of a squashed near-parallel beam are available.The intensity produces a depth-enhancing haze in the air, so intense that it is effective even with deep colours. Thebasis of most rock lighting today.

CHOOSINGLIGHTING POSITIONS

upstage from the actor - i.e. the lightis slightly less selective.



Lighting from the front

Consider the effect of a lightstartingas a vertical downlight on anactor thenmoving in a frontal planeuntil its beambecomes horizontal andthen carries on to light from below.How visible will be the actor's face,particularly eyes and teeth? To whatextent will face and body bemodelled or flattened? Whatarea ofstage will be selected and what willbe the size and direction of shadowscast on floor and scenery?

A vertical beam is the most selectivelight possible. The lit area of stage,and the shadow cast upon it, need beno wider than the widest part of theactor. However, the actor's eyes willbe black pools and a highlighted nosewill shade the mouth.

If the light comes from a littleforward of the actor, it will start toreach the eyes and mouth (providedthat she keeps her chin up and is notdefeated by a hat brim!). However,the lit area, and shadow cast, startsto extend

As the lighting comes increasinglyfrom the front, the actor's eyes andteeth receive more light. But thearea lit extends further and furtherupstage, reducing the selectivity andincreasing the likelihood of theactor's shadow hitting the scenery

As the light becomes more and morefrontal, the actor's features becomeflattened (and so also does threedimensional scenery). The lit area andthe actor's shadows increase until,when the light is horizontal, there isa lit corridor for the entire depth ofthe stage, and the actor shadowsbecome actor length.

Light from below projects an actorshadow that looms above the actorrising and falling as she movestowards and away from the lightsource. When this is the only lightingangle, the effect on the face is notat all natural. But a little from below,usually just reflected light can helpto soften the harshness of lightfrom above.

Lighting from the backand side

Now consider a light from behind.Then a light or lights from a seriesof side angles (i.e. lights at rightangles to those considered above).Once again the criteria is visibility,modelling, selectivity and shadows.

A light source behind the actor doesnot illuminate the face, but it helpsto give depth to the stage byseparating the action from thescenery through creating a haze andhighlighting head and shoulders. Theshadow of the actor is cast forward,helping the selection of areas. Sincethe light does not fall on the face,strong colours can be used.



If the light comes from a little to

one side of the actor it will start to

reach the eyes and mouth on that

side. The area lit, and the shadows

cast, will extend along the stage

floor on the other side.

Add a second light source from the

other side, and both sides of the

face will receive light. However,

there is now a second shadow and the

selected area of stage floor extends

to both sides of the actor.

face from a lower angle, it will light

more into the eyes and teeth,

although there will still be a

tendency towards a central dark line

where the beams meet down the

centre of the face.

As the angle lowers, sidelight has an

increasingly modelling effect on the

actor's face and body. This is

particularly important in dance.

When the light becomes horizontal

there will be a lighting corridor

across the whole stage. By focusing

just clear of the floor, it is possible

to lose shadows into the wings, and

the light will only be apparent when

an actor stands in it.

Finding the compromise

We normally seek to light an actor

for maximum visibility and maximum

modelling, with minimum shadow.

Additionally in many productions, we

need to select as tight an area as

possible. Which combination of

angles offers the optimum

compromise?

vertical and horizontal and midway

between front and side. However to

restrict the shadows cast and to give

a better 'join', the lights are often

positioned closer to the vertical and

to the centre.

A backlight added to the basic

crossed

pair brings depth to the scene and

generally enhances the 'look' of the

actor. The backlight can be used for

strong atmospheric colour if

required, while the crossed pair

maintain a more natural tint on the

actor's skin tones. Note: The actor is

now It by three beams with a 120°

separation between them.

The problem with 'crossed pair'

lighting (with or without a backlight)

is the extent of the spread of light

on floor and scenery beyond the area

where the actor's head is lit

(remember that head is usually about

five feet above the floor). Although

a single beam can be flat it can also

be quite tight.



As the side lighting comes from an

increasingly lower angle, the shadows

will lengthen to both sides of the

actor and a larger corridor will be

selected across the stage. As the

light hits the

The basic compromise that has long

been the standard approach is a pair

of beams crossing on to the actor

(one for each side of the face) from

positions that are both forward and

to the side of the actor. The

suggested angle is often around 45

degrees in both directions - i.e.

midway between

Adding a backlight can enhance this

flatness quite considerably - and the

selectivity is still a tightly controlled

upstage/downstage corridor without

side spillage.

For modelling, sidelights can be

added and, although they will spread

the lit area, they can be at quite

steep angles since they do not need

to make a major contribution to

visibility. Note: Four beams now light

the actor with a 90° separation

between them

SPECIALS

The major proportion of a stage lighting rig is focused to form a palette of areas and colours whose various

combinations will provide the desired fluidity of selectivity and atmosphere. However there are certain lights whose

function is so 'special' that they cannot make a significant contribution when mixing the basic palette.



For the Actor

Specials usually consist of spotlights set so tightly that the spaces they light cannot be considered as areas. Theyare often for moments when an actor has to be picked' out (perhaps only head and shoulders) on an otherwiseblacked-out stage. They need to be listed in a priority order for close scrutiny and reduction to essentials.

For Special Effects

There may be a request for equipment to produce clouds, flames, water, lightning, etc. When listing it is alwaysprudent to remember that such effects can draw attention away from the actor rather than positively support aperformance. And if the effect is essential, then the effect of light reflected from fire or water is often moretelling than a pictorial representation of the actual fire or water

For the Scenery

The proportion of the rig focused on the scenery will be very small. With the exception of skies and back or frontcloths, scenery normally gets sufficient general wash from the reflected light bouncing off the stage floor from thelights that have been set for the actors. Indeed, as discussed in the following pages, many of the basic problems oflighting design arise from difficulties in stopping actor light hitting directly on the scenery Successful lighting ofscenery depends on augmenting the diffuse reflected general light by selective highlighting of chosen scenicelements, or parts of these elements. This can vary from bold gashes to soft emphasis. Again, to be listed andreduced to essentials after a debate based on priorities and available resources.

DIVIDING THE STAGE

Dividing by Area

Once decisions have been made about the kind ofcontribution that we expect lighting to make to theproduction that we areplanning - and these contributions have been put intosome sort of order of priority - we need to break downthe stage area into the segments over which we requireindependent selective control. The required breakdownmay be symmetrical, in which case the stage plan will bedivided into something that resembles a series of areasof different sizes corresponding to the placing of theaction. Of course it could well be that there is no needfor division into what it is useful to call productionareas: all the stage may be in use all the time. In thiscase a simple division into centre and sides will allowbalancing for maximum 'enhancement' of the look of thescene. Note: Adjoining areas overlap - both side to sideand back to front. And remember to remember thatthese are areas where an actor's head is to be lit - theyore unlikely to be the some as the light patterns on thefloor

Area planning for a musical Musicals tend to have manyscenes and many selective and atmospheric lightchanges within these scenes. Therefore, unless thereare many - very many - lights available, the breakdowninto areas has to be very general. In this example thebreakdown is symmetrical because, as in so many musicalproductions, the settings consist of a symmetricalseries of wings leading to a backcloth, possibly askycloth. With the addition of cloths and scenic pieces,the method of staging gives a flexible masked actingarea with the possibility of sufficient open space fordancing and lots of entrances for a large chorus to geton and off quickly In most musicals the big moments arestaged in the downstage areas: to help both musicalbalance and the 'putting across' of numbers to theaudience. For the same reasons, much of the essentialaction takes place centre stage. The most commonselective lighting cue is to 'concentrate centre', usuallydownstage centre, by 'losing the edges'. This suggests aminimum of three areas across the stage - certainly atthe front of the stage, and probably also midstage.However, it is often quite practical to consider thewhole width of the rear of the stage as one area. This



Area planning for a play

In this naturalistic play -possibly but not necessarily in

a box set -the areas are determined to a considerable

extent by the positions of furniture and doors. And the

lighting is expected to make some logic in terms of

practical light fittings (table lamps, wall brackets, etc.)

and the natural sunshine and moonlight coming through

windows (including those in the audience's 'fourth wall').

In this particular example, we have a play where it is

desirable to focus attention at various times on the

sofa, the armchair, the table (with that essential tool of

modern drama, a telephone) and the doors. These doors

are tremendously important in any drama: some of the

key appearances and speeches are made there. But for a

long intimate scene on the sofa, it is useful to

concentrate on that sofa and loose peripheral areas like

the doors. Consider the seven areas shown here in terms

of possible combinations: the area palette gives the

director a wide range of selectivity of audience vision -

whether a subconscious fluidity (slow cues that are not

obvious) or an area selection obviously linked to the

switching of the practical lamps

provides a seven area combination that offers an area

palette giving the director considerable selectivity with

the possibility of progressive tightening from back to

front and from sides to middle.

Colour planning for a play

In a naturalistic play, colour is often used to create a

fluid atmosphere that can shift from warm cheerfulness

to cool sadness. If an area is lit with some lights in

warm tones and some in cools, the dimmers of the

control board can be used to achieve a whole series of

options from an extreme of the warm colour alone,

through the neutrality of both together, to the other

extreme of cool colour alone. Which (if any) of the

areas need to have this kind of 'double cover' of colour

tones? In this example, discussion with the director has

established that such a colour palette seems necessary

around the central areas and the desk, whereas the

upstage corners and downstage right can manage on a

warm tint only - although perhaps one that is a little

closer to a compromise neutral than the warms in the

mixable areas. In such a naturalistic production the

actual colour tints chosen are likely to be quite subtle.

Colour planning for a musical

The dialogue scenes of a musical require the subtle

colour tones that are appropriate for a naturalistic play

However, the musical numbers, particularly when solo

singers can be given isolating visibility from tightly

focused follow spots, usually call for strongly

atmospheric colouring. And many dance sequences,

where the body is relatively more expressive than the

respond well to positive use of quite strong colour This

example shows a much used technique where the colour

is applied in rather broader washes than the areas

selected for scene location. The front half of the stage

is divided into three areas, each lit from above in rather

saturated colours: a hot and cold rather than a warm

and cool. The rear half is treated as one area, also with

a hot and cold from above. From the side comes further

washes, probably in slightly less saturated hues. These

may divide the stage into bands: in this case an upstage

band and a downstage band, possibly splitting the stage

into left and right but just as likely covering the full

width. With relatively neutral colour from the front,

saturated colours from above and intermediate colours

from the side, we have a colour palette that offers

considerable scope.



face,

THE DECISION PROCESS

So how does one decide where to put the spotlights? Onmany stages and in many auditoria there is not muchchoice: but, to make the best use of the positionsavailable, it is necessary to start from an ideal andcompromise that ideal to fit reality. By WHERE, wemean where to put the light and where to point it.Traditional advice involves a lot of crossing of lightbeams - partly to help model/sculpture the actor byintroducing a partially side-light angle and partlybecause lighting diagonally across a stage provides abigger spread of light from each lamp: an importantbonus when equipment is in short supply. Crossing thebeams opens out the area lit but can cast excessiveshadows on side wall or masking. And so, with spotlightsbecoming increasingly versatile as to beam width, thereis every reason to consider using the traditionallydiscredited method of lighting the actor with lightcoming straight in from the front. Of course if this isthe only light, yes it will be flat. (And if the availablepositions are so low that an actor shadow will be thrownon to the sky, then better to come diagonally - prioritiesagain!) But with the addition of some backlight (even ifit is nearly vertical) and some sidelight, the front-litactors will come alive and the areas/ shadows broughtmore under control. There need not be precise sidelighting for every area: it can often be quite generalsince it is frequently more important in the big wideareas than in smaller tighter areas (more important,that is, in priority terms!).In the examples shown here, the traditional crossingmethod has been used for the play, while the actors inthe musical are lit' flat frontal'. But it could be viceversa. Whichever way, the next stage in the planning isto establish where the lights go and where they point.

Example plan for a play

Or ratherthan a pair, we could use a single straight in -but if so, we must make it really straight in because asingle crossing beam does not do much for the otherside of the face!

Example plan for “In the Round”

For staging in the round, light needs to come from allsides. And it should be evenly balanced to avoidfavouring one segment of audience to an extent that isnot really permissible in a staging form so democratic astheatre-in-the-round. To avoid hitting into audienceeyes, light has to come from both within the acting areaand from outside it. Angles can be closer to the verticalthan in other forms of staging because the audience iscloser to the actors and thus visibility is 'easier'.Example plan for a musical

In this musical the actors' visibility light is provided byspots in a neutral colour hitting straight in. The frontareas are covered from the auditorium, the midstageareas from a bar just inside the proscenium, and theupstage areas from a midstage bar If the stage is very



For each area of our play we need two lights. One foreach side of the actors' faces. When an area requires afull colour control of cool and warm, the number willdouble to four spots - a crossed pair in warm and a pairin cool. A spot bar immediately behind the prosceniumarch will give a suitable angle for lighting the upstageareas, but for the downstage areas a position in theauditorium is necessary Red and blue have been used toindicate warm and cool filters in the spots. Greenindicates more neutral washes that have been addedfrom back and sides. Not enough equipment? Well, do wereally need all these areas? And so many of them withboth warm and cool? (Back to priorities?)

wide, two or more lamps may be required for each areaas indicated. Strong colour comes from near verticalbacklights and medium colour from the wings (on stands,booms or ladder-frames to be discussed under 'rigging).

Note: For clarity these plans only include actor lights.The play would require light outside the window and onthe door backings, while the musical is likely to need acolour mix for the backcloth and possibly specials forelements of scene.

DECIDING WHICH LIGHTS TOUSE

Deciding which instrument to use obviously depends to alarge extent on what is available - meaning anotherexercise in listing priorities. For 'foh' (front of house)throws of any distance in the auditorium, profiles areessential, both to avoid undesirable lighting up of theauditorium from scatter light, and to allow sufficientlyprecise control of the beam to prevent spillage on to theproscenium. However in a small hall there is a lot ofmerit in considering fresnels or PCs (well barndoored) atclose range when a lot of spread is possible from a fewlamps. For onstage use, Fresnels and PCs come into theirown with fast-to-set soft edges - profiles are the mostversatile instruments but they inevitably take longer tofocus. For backlight, fresnels and beamlights arefavourite, while floods are to be thought of only forwide expanses of scenery. (Use for actor light only insituations of extreme desperation). For theatre-in-the-round, barndoored fresnels give the requiredsmoothness and spread. Existing installations in mosttheatres and halls are likely to be based on fresnels andprofiles: anyone buying new equipment should lookseriously at including a goodly proportion of the new

Fresnels have been allocated everywhere because theyhave a good smooth spread (profile edges can be verydifficult in small theatres in the round). Every spotmust have a barndoor to contain spill from the audienceeyes. Each become a pair of spots since this is the onlyway that it is possible to light fully to the sides of theacting area.Too many-spots? Then perhaps just one cover in aneutral shade (thereby halving the number on the plan)



generation PCs giving smooth soft-edge beams withoutstray scatter light and at the versatility of the variablebeam profiles.

This plan shows instruments being allocated to our playin a very orthodox way: profiles for the front-of-houseand fresnels for onstage. If a couple of PCs wereavailable, they would be a useful alternative on the endsof the stage spot bar: this is a position where anyscatter light shows up badly on the side walls of the set.Whether 500 or 1000W units are required will dependmainly 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 notso important as the BALANCE.

and utilising a couple of pairs of straight downlightersto add colour toning in warm or cool.

The actor face lights are profiles from the front andfresnels onstage, with the second bar being lesspowerful units - face light is rarely important upstage ina musical. The backlights are fresnels, although parcanswould be nice if available. For the sidelighting, profileshave been used downstage to contain the light in a tightcorridor across the front - often advisable when frontcloths or running tabs are in use. Midstage sidelightinguse fresnels for a good spread, while the optionalupstage sidelight again uses profiles to keep the lightclear of the skycloth.

THE RIG PLAN

THE PLAN is the kernel of any lighting design. It shows,at minimum: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.

A good procedure is:

1. Establish all lighting positions with Xs2. Convert these Xs to symbols of available (and/oracquirable) lighting instrument types, drawing thempointing in the approximate direction of proposed lighttravel.3. Write colour numbers inside symbols.4. Add dimmer numbers alongside symbols.5. Trace through key features of the set and stage - itis usually possible to trace through (in spaces clear oflighting drawing) enough to relate the positions of lightsto the geography of the setting and stage.

This will bring the plan to a point where it can be usedto prepare and rig the equipment. The lightingdesigner's own copy will grow many extra markings toindicate precisely where the lights are to be pointed -markings so detailed that they would only confuse ifincluded on all copies of the plan.

LISTS

From the plan, lists are prepared of the required



The plan should be drawn to scale (1" to 1 ' or 1:25). Thishelps accurate indication of light positions. And if scalesymbols are used for these lights, there is a check onspace problems: if it can be drawn on the plan, there willbe room for it on the stage. Any shapes may be used toindicate lights, but plans are more easily read if thesymbol resembles the outline shape of the light. Eitherway, the plan should certainly include a key showing thetype of lighting instrument represented by each symbol.Colour and dimmer are indicated by number: the usualconvention is to write the colour number inside thesymbol and the dimmer number alongside the symbol.Lights fixed to horizontal bars are easy to show in plan:the bar can be drawn in the position that it will occupyover the stage and its height indicated by a note (suchas + 14') written at the end of the bar. Lights fixed tovertical bars, or stacked on a series of brackets, aremore difficult to draw - they must be indicateddiagrammatically FOH lights in the auditorium areusually drawn much closer to the stage than their scaledreal distance which would make the plan inconvenientlylarge. The easiest method is to work on tracing paperover a ground plan of the scenery and stage.

number of:1. Types Of Light2. Lengths Of Cable3. Accessories4. Colour Filters5. Section Drawings

Will there be borders to mask the lights (and otherthings) hanging above the stage? If so, draw a sectionto check that all the light beams will be able to reach alldesired parts of the actors and the scenery. Usually(but not always) the heights of the borders and lightingbars can be adjusted. Only a section will determine whatthese relative heights should be, and only a section willdetermine how effective the masking arrangements willbe for an audience eye in the front row.

FOCUSING

Focusing is probably the most important part of thewhole lighting operation. Not even the most sophisticatedmarvel of a microprocessor control desk can fill in thatdark spot where the lights have not been properlyoverlapped. Nor can a hard edge be softened or adisturbing spill on to a border be shuttered off. Focusinginvolves tricky ladder work so that there is everyincentive to get it right first time - although, inevitably,it will be necessary to get at the odd spotlight betweenrehearsals for a little fine adjustment.

Focussing in comfort

If you stand with your back to the light that you arefocusing, (I) You will avoid being blinded (2) You will beable to see what the actor's light is doing to the scenery

Most profiles have an adjustment whereby the light canbe adjusted so that it is either smooth across thewhole spread of the beam, or 'peaked' to be brighter inthe middle with the amount of light falling off towardsthe edge. For most purposes it is easier to light with aneven brightness across the beam and so it isrecommended that anyone beginning to work with lightshould use an even beam until through experience theydiscover a need for a 'peaky' beam.

SOFT SPOT



VARIABLE ANGLE PROFILE SPOT

FIXED ANGLE PROFILE SPOT

No clear shadowof head,therefore head isnot lit.

Clear shadow ofhead, thereforehead is lit

If the lightingdesigner isshorter than theactor, make anallowance - checkby raising hand

What can we adjust?ON ALL LIGHTSLeft/Right & Up/Down

ON SOFT SPOTSBigger/Smallerwith optional Barndoor Rough shaping (& control of spill)

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 ProfileSpots since there is an interaction between shutters (oriris) and lens movement. Although adjusting the lens isprincipally a means of making the edge of the beamharder or softer, it will also change the size. Thereforeit is usually necessary to adjust shutters and lensalternately to get the desired combination of size andedge quality



GLOSSARY

Backlight Light coming from behind

scenery or actors to sculpt and

separate them from their

background.

Bar Horizontal metal tube of

scaffolding diameter for hanging

lights (pipe in America)

Barndoor Four-shutter

rotatable device which slides into

the front runners of fresnel and PC

focus spots to shape the beam and

reduce stray scatter light.

Battens Lengths of overhead lighting

floods arranged in 3 or 4 circuits

for colour mixing.

Beam angle Angle of the cone of

light produced by a spotlight.

Beamlight Lensless spotlight

with parabolic reflector giving

intense parallel beam

Board Contraction of switchboard or

dimmerboard. The central control

point for the stage lighting.

Boom Vertical pole, usually of

scaffolding diameter, for mounting

spotlights.

Boom arm Bracket for fixing

spotlights 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 memory

system by which individual channels

are brought under operator control.

Check Decrease in light intensity.

Colour call A listing of all the

colour filters required in each

lighting instrument.

Cue The signal that initiates a

change of any kind. Lighting cue is a

change involving light intensity

alterations.

Cyclorama Plain cloth extending

around and above the stage to give a

feeling of infinite space. Term is

often rather loosely used for any

blue skycloth, either straight or

with a limited curve at the ends.

Dead (1) The plotted height of a

piece of suspended scenery or bar

of lights. (2) Discarded items of

scenery.

Dichroic Colour filters which work by

reflecting unwanted parts of the

spectrum rather than absorbing

them in the manner of traditional

filters.

Diffuser A filter, often called a

frost,

which softens a light beam,

particularly its edge.

Dimmer Device which controls the

amount of electricity passed to a

light and therefore the intensity of

that light's brightness.

Directional diffuser A filter

which not only softens the beam but

spreads it along a chosen axis. Also

known as a silk

Director Has the ultimate

responsibility for the interpretation

of the script through control of the

actors and supporting production

team.

Discharge lamps Special high

powered

light sources whose use is normally

restricted to follow spots and

projection because of difficulties in

remote dimming by electrical means.

includes C.S.I., C.I.D. and H.M.1

lamps.

Downstage The part of the

stage nearest to the audience.

clearly defined image; but usually

used to cover the whole process of

adjusting the direction and beam of

spotlights in which the desired

image may be anything but clearly

defined.

FOH All instruments which are

'front of house', i.e. on the audience

side of the proscenium.

Follow spot Spotlight with which an

operator follows actors around the

stage.

Fresnel spot Spotlight with soft

edges due to fresnel lens which has

a stepped moulding on the front and

a textured surface on the back.

Frost A diffuser filter used to

soften a light beam.

FUF Full-up-finish. An increase to

bright light over the last couple of

bars of a musical number.

Gate The optical centre of a profile

spot where the shutters are

positioned and where an iris or gobo

can be inserted.

Gauze Fabric which becomes

transparent or solid under

appropriate lighting conditions.

Gobo A mask placed in the gate of a

profile spotlight for simple outline

projection. Also used, with

softened focus, to texture the

beam.

Groundrow A low piece of

scenery standing on the stage floor.

Also lengths of lighting placed on

the stage floor.

Group A subdivision, temporary or

permanent, of the channels in a

control system.

Hook clamp A clamp for fixing an

instrument to a horizontal bar,

usually of scaffolding diameter.



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.

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

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 themuscleoperateddiaphragm in the humaneye which adjusts the eye's apertureto changing lightintensities.

Kilowatt see wattage

Ladder Framework in the shape of aladder for hanging side lighting.

Lamps The light source within aninstrument, 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.

Pipe ends Spotlights 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 positionedinadvance 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.

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.

Spotlight An instrument givingcontrolof 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.

Tilt Vertical (up/down) movement of



Pan Horizontal (left/right)movement ofan instrument.

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

Par Lamp A sealed beam lamp withthefilament 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.

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

Resistance dimmerAn oldermechanicalform 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 rolloffilters 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.

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 Newerlamps(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 consumptionof a lamp, or the maximum availablepower from a dimmer. A kilowatt is1,000 watts. Ways The number ofchannels in a control system.

Zoom A differential movement oftwo lenses in an optical system. In a<simple 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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Stage Lighting Guide

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