Lighting Basics

Introduction

Lighting is the department people are most likely to describe as artistic and least likely to be taught properly. The result is a lot of technicians who can patch a fixture and address a universe, and cannot say why the stage looks flat — and a smaller number of people with a good eye who cannot work out why channel 47 is not responding.

Both halves are learnable and neither is mysterious. Light has four properties you control and no more. A fixture is one of three kinds. A console is a machine for remembering numbers. And an angle either puts shape on a face or it does not, which is something you can see with your own eyes the first time somebody points it out.

What this book actually does

It gives you both halves in the order they make sense. What light actually does, in terms you can see rather than measure. The three families of fixture and what each one exists for. What DMX is, why it is arranged the way it is, and what an address really means. What a console is doing when you record a look. And then the design ideas that turn a rig that works into a stage that reads.

Every chapter shows you the thing on a real job, walks you through the procedure, warns you about the failure you will actually meet, and gives you something you can take to work.

Who this is for

Somebody who will be handed lighting work in the next few months, or has already been handed it and is getting by on copying what was there last time. You do not need to have programmed a console. You do need to be willing to look at a stage and say what is wrong with it, which is a skill this book will build deliberately.

If you have read AV Fundamentals 101 you already have the shape of a signal chain, and lighting has one. If you have not, you will still be fine; the ideas are introduced as they arrive.

What this book will not do

It will not teach you a particular console. Every desk names things differently, and a book that taught you one would be wrong in a year and useless on the next job. It teaches what all of them are doing, so the manual for any of them makes sense.

It will not make you a lighting designer. That is a career, not a chapter, and it is built on top of everything here rather than instead of it. What this book will do is take you from "lighting is the department I do not understand" to being genuinely useful on a lighting crew, which is the step that actually gets you booked.

How to Use This Book

Each chapter follows the same shape, and the shape matters more than it might look. You read the ideas, then you see them play out in a real situation, then you get the procedure, then you find out what goes wrong, then you practice, then you get a checklist you can actually take to work.

1. Read the chapter body first. This is the understanding layer, and it is written to be read straight through.
2. Read On the job. The same material as a real situation on a real show, which is where it stops being abstract.
3. Work through How to do it. These are procedures you can follow on a job this week.
4. Study What goes wrong. Experienced technicians are not people who never make mistakes; they are people who recognise mistakes early.
5. Do the exercise before reading the answer key. Recognition feels like learning and is not.
6. Take the checklist with you. Photograph it on your phone. Use it until you no longer need it.

Keep a notebook

One habit is worth starting today, before the first chapter: keep a small notebook and write the technical details in it as you meet them. Lighting is full of numbers you will need exactly and will not remember — how many channels a fixture takes in each of its modes, what address the last one on the truss ended at, which console menu hides the patch, which fixtures in the house stock need a five-pin cable and which will take three.

Write it by hand rather than photographing this page. Copying a number puts it on paper; rewriting it in your own words is what puts it in your head, and deciding how to phrase it is most of the learning. Add to it as you work: the venue whose house rig is patched in a strange order, the fixture that needs a full power cycle before it will take a new address, the position that always throws a shadow on the screen.

Then use it twice. Read a few pages on the way to a job, which takes five minutes and turns things you half-know into things you know. And carry it on the job, because the moment you need to know how many channels a fixture takes is never a moment when you can stop and look it up.

A note on the words

Lighting vocabulary is inconsistent and regional, and you should expect that rather than be caught by it. A conventional fixture is a lantern in one country and a can in another. A look is a scene, a state, a preset or a memory depending on whose desk you are standing at. Channel means a fader on the console to one person and a single DMX parameter to another, and both are correct.

None of that is worth arguing about. What matters is that you can say what a thing does, because a person who can describe the function will be understood anywhere, and a person who only knows one desk's word for it will be understood in one building.

A note on safety

Lighting puts you closer to the genuinely dangerous parts of this trade than almost any other department. Fixtures are heavy and they go above people. They run on mains power. They get hot enough to burn skin and set gel alight. Moving heads move without warning when they are powered up, and they do not care where your hand is.

This book gives you awareness, not authorisation. Rigging and electrical work are qualified trades with rules that exist because people have died. If you are ever unsure whether you are qualified to do something, you are not — ask. Nobody in this industry has ever been fired for asking whether a thing was safe.

Where this book sits

This book assumes you have read AV Fundamentals 101, or that you already know what is in it.

Experience counts instead. If you have experience on crews where you have already watched a rig go up, and know what a fixture and a console are for, start here.

If none of that is true yet, read AV Fundamentals 101 first.

What pairs with this

• The Art of Light: Lighting Aesthetics — trains the eye the way this book trains the hands

Where it leads

These are not steps in an order. Take whichever one fits.

• Lighting Operation — to run a desk for a living
• Lighting Design — to decide what the stage should look like rather than build it

How Light Behaves

Before any fixture, the four things light can do. Everything in this trade — every note a designer gives, every complaint a client makes, every fault you will ever fix — changes one of four properties, and there is no fifth. Learning them is an afternoon's work and it makes the rest of the subject legible.

The four properties you control

Light has four properties you can change, and that is the entire list. Intensity, colour, beam, and position.

That sounds too simple to be useful and it is the most useful thing in this book. Every note a lighting designer gives is one of the four. "Too bright" is intensity. "Too cold" is colour. "Too tight" is beam. "It is hitting the screen" is position. A designer who says "it needs more energy" is asking for a change to one or more of the four, and the skill of working with them is translating the vague sentence into the specific knob.

It also works in reverse, which is where it earns its keep as a technician. When a stage looks wrong and you cannot say why, run the four in order. Is there enough light? Is it the right colour? Is it the right size and shape? Is it coming from the right place? One of those four will be the answer, and usually the fourth one, because direction is the property people notice least and the one that does most of the work.

Keep this list in your head as the frame for the rest of the book. Fixtures are devices for delivering the four. A console is a machine for storing values of the four over time. And a lighting design is a set of decisions about the four, repeated for every moment of a show.

Intensity and dimming

Intensity is how much light a fixture puts out, and it is the property everybody understands and most people over-use.

It is expressed as a percentage on a console, from zero to full, and it is set either by dimming the fixture or by controlling it directly. A conventional fixture has a lamp with no brain in it, and it is dimmed by a separate device — a dimmer — that varies how much power reaches it. An LED or a moving fixture dims itself, electronically, from an instruction it is given.

Two things about intensity surprise people. The first is that the eye does not respond to light the way a meter does. Take a fixture from full to fifty percent and the stage does not look half as bright; it looks slightly less bright. Your perception of brightness runs closer to a curve than a straight line, which is why consoles and dimmers apply a dimmer curve rather than a linear one, and why the difference between ten and twenty percent is much more visible than the difference between eighty and ninety.

The second is that a dimmed tungsten lamp changes colour as well as level. Wind a conventional fixture down and the light goes warmer and more orange — the filament is running cooler, and cooler filaments make redder light. Designers use this deliberately, and it is also why a rig of conventionals at forty percent looks like candlelight rather than daylight. LED fixtures do not do this unless they have been built to imitate it, which many now are, precisely because people missed it.

The practical lesson for a technician is that intensity is rarely the fix. When something looks wrong, the reflex is to bring it up, and bringing everything up gives you a brighter version of the same problem. Flat light at full is still flat light.

Colour

Colour does more work than any other property and it is the one that changes how a scene feels rather than what it shows.

There are two ways to make it. The old way is a gel — a sheet of coloured plastic in a frame, clipped to the front of a conventional fixture, which works by subtraction: white light goes in, the gel absorbs everything except the colour you want, and what is left comes out. That absorbed light becomes heat, which is why deep colours run hot and burn out, and why a deep blue gel is dramatically dimmer than an open white fixture. You are throwing most of the light away to get the colour.

The new way is an LED fixture that mixes colour additively. Red, green and blue emitters — usually with amber, white or lime added, because red-green-blue alone makes poor pastels and worse skin tones — are driven at different levels, and the combination is the colour. Nothing is absorbed and nothing is thrown away, which is why LED colour is efficient and why a saturated blue from an LED is far brighter than the same blue through a gel.

Colour temperature is the other half of the vocabulary and it causes real confusion because the naming is backwards. It is measured in kelvin, and lower numbers are warmer while higher numbers are cooler. A tungsten lamp is about 3200 K and reads as warm and orange. Daylight is around 5600 K and reads as cool and blue. That is the opposite of what the words suggest, and everybody trips over it once.

What matters on a job is that colour has to agree with itself. Two fixtures of different types lighting the same face will rarely match at the same nominal setting, because their emitters and their lamps are not the same. And on any job with a camera, the whole rig has to agree with what the camera is white-balanced to, or faces go green or orange on the recording while looking perfectly fine to the room.

Beam and position

Beam is the size and shape and quality of the light a fixture throws. Position is where it is hung and where it points — and on a moving fixture the two controls that change it are called pan, which swings it left and right, and tilt, which swings it up and down. You will hear both words on every job. Between them they do most of the work that people credit to intensity.

Beam angle is the number that describes the size: a narrow fixture might be ten or fifteen degrees and throws a tight pool at distance, and a wide one might be fifty degrees or more and washes a broad area from close. The rule you need is that a beam gets bigger and dimmer with distance in the same relationship as any other light — double the throw distance and the pool is twice as wide and roughly a quarter as bright. A fixture that was perfect on a low trim looks like a dim smear from a high one.

Edge quality is the other half of beam. Some fixtures give a hard-edged pool you can put exactly where you want it and shape with shutters or a gobo; others give a soft edge that blends invisibly into the next one. Hard edges are for making a shape somebody notices. Soft edges are for making light nobody notices, which is most of the light on most stages.

Position is the property that separates lighting from illumination, and it is the one beginners ignore. Light from directly in front flattens a face: it removes shadow, and shadow is how eyes read a three-dimensional shape. Light from the side puts shape back and can be dramatic or unflattering depending on how far round it goes. Light from behind separates a person from the background and is the single most valuable thing you can add to a badly lit stage. Light from directly above makes eye sockets into caves and is unkind to everybody.

This is why "it looks flat" almost never means "it needs to be brighter". It usually means everything is coming from one place, and the fix is a fixture from somewhere else — often at a lower intensity than the ones already on.

The four properties, and what changes them

The frame for everything else in the book. When something looks wrong, go down this table in order.

Numbers worth carrying

Rules of thumb, not specifications. All of them vary by equipment; all of them are the right shape.

On the job

A panel session in a hotel ballroom. Four people at a table, a house rig of six fixtures on a front truss, and a client who says the stage looks "flat and a bit sad" without being able to say more than that.

The reflex is to bring the fixtures up, and somebody has already tried it. At full, the stage is now a brighter version of flat and sad, and the panellists are squinting.

Run the four properties instead. Intensity: there is plenty of light, so that is not it. Colour: everything is open white at around 3200 K, which is inoffensive rather than wrong. Beam: the pools overlap and cover the table, so coverage is fine. Position: every one of the six fixtures is on the front truss, pointing straight at the panel from the front.

There it is. Front light only, which removes every shadow from four faces and makes them read as flat as a passport photograph. The fix is not more light, it is light from somewhere else — two fixtures repurposed from the front truss to a position behind and above the table, at maybe forty percent, to put an edge on the tops of their heads and shoulders.

The stage gets slightly less bright and looks dramatically better, and the client says it looks "more professional" without knowing why. What changed was position, which is the property nobody names and the one that was doing the damage.

How to do it

Diagnosing a stage that looks wrong, when nobody can say what is wrong with it. Two minutes, and it works on any rig of any size.

1. Stand where the audience will be, not where the console is. A stage is judged from the seats, and a lot of lighting faults are invisible from behind the desk.
2. Ask about intensity first, because it is quickest to rule out. Is there enough light on the faces to see them comfortably? If yes, stop touching it.
3. Ask about colour. Does it agree with itself across the stage, and does it suit the event? Two fixtures on one face that do not match is a fault; a colour you personally would not have chosen is not.
4. Ask about beam. Is the light where it should be, and is it spilling where it should not — onto a screen, into the audience, onto a wall behind?
5. Ask about position last, and expect the answer to be here. Where is every fixture coming from? If the answer is 'all from the front', that is your flat stage.
6. Change one property at a time and look again from the same seat. Changing three at once teaches you nothing about which one mattered.
7. Write what worked in your notebook, with the room. The same ballroom next month will have the same house rig and the same problem.

What goes wrong

Practice it

Work these out before reading the answers. All six are questions you will be asked on a job, usually by somebody who cannot phrase them this clearly.

Fixtures: The Lights Themselves

A fixture is a device for delivering the four properties, and there are three families of them. What separates the families is not really the technology — it is what each one costs you in money, weight, power and time, and which of the four properties it will let you change once it is in the air.

Conventional fixtures

A conventional fixture is a lamp in a metal housing with a lens on the front and no brain inside it. It has exactly one thing you can control remotely — how bright it is — and everything else about it is set by hand before the show and stays set.

That sounds like a limitation and for decades it was simply what lighting was. The colour is whatever gel you clipped into the front. The beam is whatever the lens gives you, adjusted by hand if the fixture has a way to do it. The direction is wherever you pointed it up a ladder, and if it is wrong you go back up the ladder.

There are two shapes worth knowing. A profile — often called a Leko or an ellipsoidal depending on where you work — makes a hard-edged beam you can shape precisely, with shutters that cut the edges square and a slot for a gobo, which is a metal or glass cut-out that projects a pattern. It is the fixture you use when the light needs to be exactly somewhere and nowhere else. A fresnel or a PAR gives a softer, wider pool that blends into its neighbours and is what you use when you want light nobody notices.

Because a conventional has no electronics, it cannot dim itself. It is plugged into a dimmer, which varies the power reaching the lamp, and the console controls the dimmer rather than the fixture. This is why conventionals need a dimmer rack and why a venue that has gone fully LED has often thrown its dimmers out.

What conventionals still have going for them is that they are cheap, extremely reliable, and produce a quality of light that many designers still prefer — a warm, full-spectrum light that flatters skin and that dims into candlelight. What they cost you is labour: every change is a person on a ladder.

Moving-head and intelligent fixtures

A moving head is a fixture with motors in it, and it turns the properties you used to set by hand into properties the console can change during the show. Pan and tilt move the beam. Colour wheels or mixing systems change the colour. Zoom changes the beam angle, and gobo wheels change the pattern. Everything a person on a ladder used to do, a console can now do in half a second, repeatedly, in front of an audience.

The cost of that is complexity in every direction. A moving head takes a lot of control channels — often twenty or thirty, sometimes far more, depending on the mode you put it in — where a conventional takes one. It is heavy, so rigging matters. It draws real power and it is expensive. It has motors, which means it has moving parts, which means it will eventually fail in a way a lamp in a can never does.

Two practical points matter more than the specifications. The first is that a moving head does not know where it is when you power it up, so it homes itself — it runs its motors to their limits to find them. That means every fixture on the truss swings through its full range on power-up, which is why nobody should be near them when they are switched on, and why a fixture pointing at the audience during a power cycle is a genuine problem rather than an embarrassment.

The second is that moving heads are slow compared with your expectations. A head takes a real fraction of a second to travel, and colour and gobo wheels take time to spin into position. Programming that ignores this gives you a cue where the light arrives before the colour does. Experienced programmers build in the travel time deliberately, and often hide the movement in darkness or behind a change of state.

LED fixtures and a note on haze

An LED fixture makes light from light-emitting diodes rather than from a hot filament, and it has quietly taken over most of the industry in about fifteen years.

What it gives you is efficiency and control. It draws a fraction of the power of an equivalent conventional, which changes what you can put on a circuit. It runs cool enough to touch and cool enough to sit near people. It mixes its own colour additively, so any colour is available instantly with no gel and no light thrown away. And it dims itself, so it needs no dimmer — it plugs into constant power and takes its instructions over control.

What it costs you is consistency and, sometimes, quality of light. Two LED fixtures from different manufacturers set to the same nominal colour will very often not match, because their emitter sets are different. Cheap LED fixtures render skin badly — faces look slightly wrong in a way that is hard to name until you see a good fixture beside a bad one. And low-end LED dimming can be visibly steppy at the bottom of the range, or can flicker on camera even when it looks perfectly smooth to the eye, which is a serious problem on any job that is being filmed.

Haze belongs in this chapter because it is what makes any of these fixtures visible as beams. A beam of light in clean air is invisible — you see the pool where it lands, not the light travelling to it. A haze machine puts a fine, even suspension in the air so the beam itself can be seen, and it is the difference between a concert that looks like a concert and one that looks like a lit room. Fog and smoke are different products with different behaviour: haze is fine and hangs evenly for a long time, while fog is denser and dissipates in visible clouds.

The practical warnings are worth carrying. Haze sets off smoke detectors, which means the venue and the fire officer must be told in advance and the system may need to be isolated by somebody authorised to do it. Haze needs time to spread evenly, so it goes on well before doors rather than at the moment somebody wants a beam. And some people react badly to it, which is a reason to check with the venue and the client rather than a reason to skip it.

The three families, and what each costs you

Choose by the trade-off rather than the category. Every row here is a real decision somebody makes on a load-in.

The two conventional shapes

Names change by country. The function does not.

On the job

A product launch on a small stage. The client has seen a video of a concert and wants "the beams" — the visible shafts of light crossing above the audience — and the budget runs to eight moving heads.

The heads go in and they work, and at the first rehearsal there are no beams. There are eight pools of light on the floor and nothing in the air, and the client is confused because the fixtures are clearly on.

The missing ingredient is not a fixture. Light in clean air is invisible; you only ever see where it lands. What makes a beam visible is something in the air for it to scatter off, which means haze — and haze was not on the list because nobody thought of it as lighting equipment.

Two more things then surface, and both are the sort of thing that turns a small problem into a large one. The venue's smoke detection covers the room, so hazing without warning would empty the building; that needs the venue's technical contact and probably an isolation by somebody authorised. And haze takes twenty minutes or more to spread evenly, so it has to be running well before doors rather than switched on when a beam is wanted.

None of this is a fixture problem, and all of it is a lighting problem. It is a good illustration of why the department is bigger than the lights in it.

How to do it

Choosing fixtures for a job, before anybody quotes it. This order stops you specifying a rig the room cannot power, hang or fit.

1. Start from what has to change during the show. If nothing moves and nothing changes colour, conventionals or basic LED will do it, and everything else is money spent on capability you will not use.
2. Check the throw distances from the positions you actually have. Beam angle is chosen for the throw, and a fixture that suits a 5-metre trim will not suit a 12-metre one.
3. Add up the control channels before you commit. A rig of moving heads in a high-resolution mode can exceed a universe faster than people expect, and finding that out on site is expensive.
4. Add up the power. LED changes what a circuit can carry, and conventionals plus dimmers change what the venue has to provide. This is a conversation with the venue, not an assumption.
5. Add up the weight and confirm the rigging. Moving heads are heavy and they go over people, which makes this a qualified person's decision rather than yours.
6. Decide about haze early. If beams are wanted, haze is not optional, and the venue's fire system has to be part of the plan days ahead.
7. Check that fixtures lighting the same faces are the same model where you can manage it, because matching different LED fixtures by eye costs time you will not have.

What goes wrong

Practice it

Six load-in questions. Answer them before you look.

DMX: How Fixtures Are Controlled

This is the one genuinely technical chapter in the book, and it is worth twenty concentrated minutes because almost every lighting fault you will ever be handed lives in it. DMX is not complicated. It is a very simple idea applied at scale, and once you can picture what a fixture is actually listening to, addressing stops being guesswork.

What DMX is

DMX is the language a lighting console uses to tell fixtures what to do, and it is much dumber than people expect. Properly it is DMX512, and the 512 is the whole idea.

Picture a row of 512 numbered slots. Forty times a second, the console shouts the entire row out loud, in order: slot one is 255, slot two is 0, slot three is 128, and so on to slot 512. Every fixture on the line hears all of it. Each fixture has been told which slot to start listening at, counts off the slots it needs from there, and ignores everything else.

That is DMX. There is no addressing in the network sense, no acknowledgement, no error checking, and no way for a fixture to answer back. The console does not know what is out there and does not care. It shouts, and whatever is listening acts.

Two consequences follow and both matter on a job. Because there is no feedback, the console will happily tell you a fixture is at full while the fixture is unplugged, unpowered or broken. The console's display is a record of what it is saying, never of what is happening. And because everything hears everything, two fixtures told to start at the same slot will do exactly the same thing, forever, and no amount of console work will separate them.

The 512 slots are one universe. A universe is the unit everything else is counted in, and running out of one is a normal, planned-for event rather than a crisis.

Channels and addressing

A channel is one of those 512 slots — one controllable parameter, taking a value from 0 to 255. Confusingly, "channel" also means a fader on a console, and both usages are correct and common. When the distinction matters, people say DMX channel for the slot.

A fixture's address is the slot it starts reading from. A simple dimmer channel needs one slot: give it address 12 and it reads slot 12 and nothing else. An RGB LED wash needs three: give it address 20 and it takes 20 for red, 21 for green, 22 for blue. A moving head in a full mode might need thirty: give it address 100 and it occupies 100 through 129, and the next fixture cannot start before 130.

This is the whole of addressing, and it is why addressing goes wrong in exactly one way: overlap. Address the next fixture at 120 instead of 130 and it starts reading slots that the first fixture is also reading, and the two will interfere in ways that look random and are not. The classic symptom is a fixture that pans when you change another fixture's colour.

Because of this, the sensible practice is not to pack addresses tightly. Leave gaps — start fixtures at round numbers like 1, 21, 41, 61, or on tens and hundreds — so a fixture put into a mode that needs more channels does not silently collide with its neighbour. The few slots you waste cost nothing; the collision costs an hour with a ladder.

Two other things bite regularly. Many fixtures have several modes, taking a different number of channels in each, and the address you set is only correct for the mode the fixture is actually in — a fixture that has quietly reverted to a different mode will read the wrong slots for everything after it. And some fixtures need a full power cycle before a new address takes effect, so an address that was set correctly and appears not to have worked may simply not have been applied yet.

Universes and modern transport

One universe is 512 channels, which used to be an enormous amount and is now a small rig. Twenty moving heads in a high-resolution mode can exceed it on their own, so any job larger than a couple of trusses runs multiple universes, and each one is a separate, independent set of 512.

Traditionally each universe is one physical run of DMX cable. It is five-pin XLR — a locking connector that looks like a microphone cable's bigger relative, and the reason it is five-pin rather than three is precisely so nobody plugs audio into it. Fixtures are daisy-chained: the cable goes into the first fixture, out of it, into the next, and so on. The chain wants a terminator at the far end, a small plug with a resistor in it that stops the signal reflecting back down the line. A missing terminator often works fine and sometimes produces intermittent flicker that is very hard to diagnose, which is the worst of both worlds.

A run has practical limits — the standard's guidance is around 32 devices and a few hundred metres, and beyond that you use a splitter, which is to DMX what a distribution amplifier is to video: one in, several buffered outs.

Modern rigs increasingly carry DMX over a network instead, as Art-Net or sACN. Both do the same fundamental job — they wrap universes in ordinary network packets and send them down ordinary network cable — and the practical gain is enormous: many universes on one cable, standard network switches and infrastructure, and long runs without splitters. The fixtures at the end still speak plain DMX; a node converts the network back into five-pin universes near the truss.

What this changes for a technician is that lighting faults can now be network faults. A universe that has vanished may be a switch, a cable, an IP address or a node rather than anything to do with lighting at all, and knowing which questions belong to which layer is what makes somebody useful on a modern rig.

DMX, in the numbers that matter

Six figures. Between them they explain most of what a rig will do and most of what it will refuse to do.

Counting an address

The only arithmetic in lighting, and the source of nearly every patching fault.

On the job

A corporate awards evening. Twelve LED washes and six moving heads on two trusses, patched by somebody else the day before, and one wash on the upstage truss that changes colour whenever anybody moves a moving head.

It looks like a fault in the fixture and it is not. Two devices are reading the same slots, and the way to prove it takes about a minute: bring every fixture to zero, then push one moving head's pan on its own and watch what else changes. The wash changes. They overlap.

The addresses tell the story. The moving heads were addressed on hundreds — 100, 130, 160 — which is sensible. The washes were addressed tightly from 1 upward in fours, and somebody, running out of room, put the last one at 128. In a twelve-channel mode the moving head at 130 is clear of it, but the wash at 128 takes 128 through 131, so it is reading two slots that belong to the head.

Re-addressing that one wash to 40, in the gap left below the moving heads, fixes it permanently. The lesson is not about that fixture. It is that addresses should be laid out with gaps from the start, because the few slots you waste cost nothing and the collision costs a ladder, an hour, and a rehearsal.

How to do it

Patching a rig from scratch so it does not fight itself. Do this on paper before you touch a fixture.

1. Write down every fixture, its mode, and how many channels that mode takes. The mode matters as much as the model, because the same fixture takes different numbers of channels in different modes.
2. Add the channels up per universe before you start. If the total is anywhere near 512, split it across universes now rather than discovering the ceiling halfway up a ladder.
3. Lay out addresses with deliberate gaps, on round numbers. Fixtures at 1, 21, 41, 61 are easier to remember, easier to change and far harder to collide.
4. Group by position and type, so the upstage washes are one block and the front truss heads are another. A patch that follows the rig is a patch you can debug from the floor.
5. Set the address on each fixture and write it down, on paper and on the fixture itself with tape if the venue allows it.
6. Power-cycle anything whose address does not appear to have taken. Some fixtures only apply a new address on a restart.
7. Test each fixture individually before you patch the console — one fixture, to full, on its own, and confirm the right light comes on.
8. Then patch the console to match your paper, and test again by position: every fixture on the upstage truss, then every fixture on the front.

What goes wrong

Practice it

Seven questions, and the arithmetic ones matter most. Work them out before you look.

The Console & Programming Basics

A console looks like the hardest object in the room and is the easiest idea in the book. It does not make light and it does not know anything about your rig that you have not told it. It is a machine for remembering numbers and playing them back in order, and every button on every desk ever built does one of three jobs.

What the console does

A lighting console is a machine for remembering values and playing them back in order. That is the whole function, and holding onto it is what stops an unfamiliar desk being frightening.

Everything on the surface of any console does one of three jobs. Select: which fixtures am I talking to. Set: what values am I giving them. Store: remember that, under a name or a number, so I can get it back later. Every desk in the world, from a two-hundred-pound unit to a console the size of a table, is those three verbs with different amounts of surface area and different words for them.

What the money buys is not different capability so much as speed and scale. A larger desk handles more universes, gives you more physical faders so more things are reachable without menu-diving, offers better tools for building complex looks quickly, and provides redundancy — a backup desk that tracks the main one and takes over if it fails, which matters when the show is live and the alternative is darkness.

What no console does is tell you the truth about your rig. It knows what you patched, not what is out there. It will show a fixture at full when the fixture is unplugged, because DMX has no feedback and the desk is reporting its own intention. This is worth repeating in the console chapter because it is where people forget it: the screen is a record of what you asked for.

Channels, fixtures, and patching

Patching is the act of telling the console what is out there and where it lives. Until you patch, the desk knows nothing; after you patch, it can offer you a fixture by name and handle the DMX arithmetic for you.

For each fixture you tell the desk three things: what it is, where it is addressed, and what you want to call it. The what — the fixture type, chosen from the console's library — is what lets the desk know that this device has pan on its first channel and a colour wheel on its fifth, so that when you ask for red it sends the right value to the right slot. The where is the DMX address you set on the fixture itself. The name or number is for you.

Two habits separate a patch that helps from one that fights you. Number fixtures in a way that matches the rig, not the order you happened to unpack them — front truss 1 to 8, upstage truss 11 to 18, floor 21 upward. A patch that follows the physical rig means that when somebody says "the third one from the left is out", you can find it from the desk without a diagram. And group fixtures as you patch: all the front wash, all the upstage heads, all the floor units. Groups are the difference between selecting eight fixtures in one press and selecting them one at a time, forty times an evening.

The patch is also the first thing to suspect when a fixture behaves oddly and its address is right. A fixture patched as the wrong type will respond, because the values are arriving, but it will respond wrongly — you ask for green and it tilts, because the desk is sending green's value to the slot that this particular fixture uses for tilt.

Looks, cues, and cue lists

A look is a set of values across the rig at one moment — these fixtures at these levels, in these colours, in these positions. The word varies: a look, a scene, a state, a preset, a memory. They all mean the same thing.

A cue is a look with timing attached, stored so it can be recalled reliably. The timing is what makes it a cue rather than a snapshot: a fade time says how long the change takes, so a cue can snap in an instant or bleed across ten seconds. Most cues on most shows are a few seconds, and the difference between two seconds and five is the difference between a change people notice and one they only feel.

A cue list is those cues in order, and it is the show. The operator presses one button — go — and the desk moves the rig from where it is to the next stored state over the stored time. That single button is the point of the whole system: on a show with a hundred lighting changes, the operator's job is to press go at the right moment, and everything about which fixture does what was decided in rehearsal when there was time to think.

Two ideas about cue lists are worth having early because they explain a lot of behaviour that otherwise looks like a bug. The first is tracking: on many consoles, a value set in one cue stays until something changes it, rather than being reset to zero each time. That is enormously efficient — you only record what changes — and it also means an unwanted level can follow you through twenty cues until you find where it started. The second is that fade times are usually independent for level up, level down and other parameters, so a cue can bring one thing up slowly while taking another out fast, which is how a change reads as smooth rather than as a switch.

Tracing a lighting signal

A fixture is not responding, somebody is waiting, and this is the fault you will actually be handed. It has a method, and the method is the same one that works everywhere in this trade: start at one end and move one stage at a time.

The chain is short. The console decides a value. The value travels as DMX, over cable or over a network and a node. It arrives at the fixture, which is either powered or not. And the fixture, if it is powered and has been addressed correctly and patched correctly, makes light.

Start at the fixture, not at the desk, because the fixture is where the evidence is. Is it powered — is there a light on it, a display, a fan? An unpowered fixture is the single most common cause and the least interesting one, and checking it takes four seconds. If it is powered, does it show that it is receiving data? Most fixtures indicate this somehow, and a fixture with power and no data tells you the fault is in the run rather than in the fixture.

If it has power and data and still does nothing, the question becomes what it is listening to. Check the address on the fixture itself, and the mode, and compare both with what the console was told. A fixture addressed at 130 and patched at 100 will sit there perfectly healthy, receiving data, ignoring you.

And test the fixture in isolation before concluding anything. Most fixtures have a local test or manual mode that lights them up with no console involved. If it lights in local mode, the fixture is fine and everything you are looking for is upstream. That one step splits the problem in half and takes under a minute.

The trap, as everywhere in this trade, is changing several things at once. Re-address it, re-patch it, swap the cable and power-cycle it, and something will start working and you will have learned nothing, and it will happen again in the second half.

The kinds of desk you will meet

The three verbs are the same everywhere, but the box they live in varies enormously, and knowing which one you are looking at tells you immediately what the night is going to be like. The dividing line is not price and it is not size. It is what the desk can remember.

A dimmer pack with faders on the front is the simplest thing that counts. It has no memory at all: one fader per circuit, and whatever you are holding is what the stage is doing. Village halls and small schools still run on these, and there is nothing wrong with them for a rig that never changes.

A two-scene preset board is the same idea with a trick. Two rows of faders and a crossfader between them: you set the next look on the bottom row while the top row is live, then crossfade. It still remembers nothing, but one person can run a whole play on it, and generations of theatre technicians learned on exactly this.

A basic DMX controller is the first box in this list with any memory at all — banks of channel faders, a few scenes you can store, and usually a chase function. It is what turns up in a box with a set of LED pars. It will remember a handful of looks, it knows nothing about fixture types, and you address everything by hand.

A memory desk is where the job changes. It records cues with fade times, it has a fixture library so it knows a moving head has pan and tilt rather than just channels seventeen to twenty-eight, and it plays a show back in order. Anything from a small theatre desk upwards is in this category, and this is the first rung where the console is doing arithmetic on your behalf.

A full-size console is a memory desk with room to work: several universes, an effects engine for building movement without programming every step, a proper fixture library, and — the part that matters on a live show — a backup desk that tracks the main one and takes over if it fails. What the money buys is speed, scale and safety, not a different idea.

And a software console is any of the last two running on a laptop or tablet with a small USB-to-DMX box on the end. The software is often the same software the big desk runs. What you lose is surface area: everything is a menu until you plug in a wing, which is a slab of physical faders and buttons with no computer inside it, there purely to put your hands back on the show.

Which desk, and what it can remember

Three verbs, every console

Names change by manufacturer. The three jobs do not, which is why a person who knows the model can pick up an unfamiliar desk.

The lighting chain, and where it breaks

Four links between a decision and a photon. When a fixture does not respond, one of them is broken.

On the job

A conference stage, forty minutes before doors. The rig was working an hour ago, and now one moving head on the upstage truss does nothing while its five neighbours are fine.

The console says it is at full and in position. That is not evidence of anything, so go and look at it.

From the floor, the fixture's display is lit, its fan is running, and its data indicator is showing that DMX is arriving. So power is good and the run is good, and everything upstream of the fixture is proven in about ten seconds without touching the desk.

That leaves what it is listening to. Its display shows address 130. The console's patch says 100. Somebody re-addressed it during the afternoon — probably while chasing an overlap on a different fixture — and did not update the patch.

Two ways to fix it, and it is worth knowing which is right. Re-address the fixture back to 100 to match the patch, up a ladder. Or re-patch that fixture to 130 on the console, from where you are standing, in fifteen seconds. Both work; the second one is right, because there is no ladder in it and no reason to prefer the old number.

Then write it down, because the paperwork now disagrees with the rig, and the next person to touch it will believe the paperwork.

How to do it

A fixture is not responding. This order finds it, and it works whether the rig has six fixtures or two hundred.

1. Go and look at the fixture rather than at the console. The desk can only tell you what it is saying, and what it is saying is not in question.
2. Check power first. Is there a display, a fan, an indicator? An unpowered fixture is the most common cause and takes four seconds to rule out.
3. Check whether the fixture shows that data is arriving. Power but no data means the fault is in the run, and you have just halved the problem.
4. Put the fixture into its local test or manual mode. If it lights up with no console involved, the fixture is fine and everything you want is upstream.
5. Compare the address AND the mode on the fixture with what the console was told. A fixture addressed at 130 and patched at 100 is healthy, receiving data, and ignoring you.
6. Check what type it is patched as. A fixture patched as the wrong model responds wrongly rather than not at all — you ask for colour and it tilts.
7. If the run is suspect, work from the last fixture that responds to the first that does not. The fault is between them.
8. Change one thing at a time, and put back anything that did not help. Then update the paperwork so the rig and the patch agree again.

What goes wrong

Practice it

Seven questions. The tracing ones are the ones you will be paid for.

Design Basics & Putting It Together

Everything so far has been how to make a fixture do what you tell it. This chapter is about what to tell it, which is a different kind of knowledge and is learned by looking rather than by reading. What a book can do is give you the handful of ideas that make looking productive, and they are fewer than you would think.

The functions of light

Before deciding where a fixture goes, it helps to know what you are asking it to do. Light on a stage does four jobs, and almost every fixture in a rig is there for one of them.

Visibility is the first and the one nobody thanks you for. People must be able to see the faces. It sounds too obvious to state, and it is the requirement most often sacrificed by somebody chasing an effect — a stage can be beautifully lit and useless, and on a corporate job that is a failure however good the photographs look.

Selective focus is the second: directing attention. An audience looks at the brightest thing in its field of view, more or less without choosing to. Bringing one area up and letting the rest fall away tells people where to look far more effectively than anything said from a lectern, and it is why a single presenter in a pool of light holds a room better than a presenter on an evenly lit stage.

Modelling is the third and the one that separates lit from illuminated. Light reveals three-dimensional shape through the shadows it creates, and a face with no shadow on it reads as flat. This is why direction matters so much and why front light alone always disappoints. Modelling is what makes a person look like a person rather than a photograph of one.

Mood is the fourth: colour, level, contrast and how they change. It is the one people talk about most and the one that only works when the other three are already right. A moody stage where nobody can see the speaker is not moody, it is badly lit.

The useful discipline is to ask which function each fixture is serving. A fixture that serves none of the four is decoration, and decoration is fine — but it should be a decision rather than an accident, especially when power, weight and channels are finite.

Angles and a basic approach

Where light comes from does more than anything else to determine whether a stage works, and there is a small vocabulary of positions worth knowing by name.

Front light comes from in front of the performer, and it provides visibility. On its own it flattens, because it fills in every shadow the eye uses to read shape — which is exactly why a passport photograph looks the way it does. Almost every disappointing stage in the world is front light alone.

Front light at an angle, roughly forty-five degrees to the side and forty-five degrees up, is the classic key position and the single most useful improvement over flat front light. It lights the face while leaving enough shadow on the far side to give it shape. This is the position most portrait photography uses, for the same reason.

Back light comes from behind and above, and it is the cheapest transformation available. It puts a rim of light on the hair and shoulders, which lifts a person away from the background and gives the stage depth. On a badly lit stage with a limited budget, adding back light is almost always the highest-value change, and it usually works at a lower intensity than people expect.

Side light comes from the wings, at or near head height, and it is dramatic and unforgiving. It rakes across a face and reveals every texture, which is wonderful for dance and cruel to a keynote speaker.

Top light comes from directly overhead, makes eye sockets into caves, and is used deliberately for effect and almost never as the main source on a face.

The basic approach, when you have nothing else to go on, is short. Start with a key at around forty-five and forty-five, which gives you visibility and modelling in one fixture. Add a softer fill from the other side at a lower level, to open the shadows without erasing them. Add back light to separate the subject from the background. Then, if you have fixtures left, light the background separately so it is a deliberate colour rather than whatever spills onto it. That sequence is not a style; it is a functional baseline that will make almost any stage acceptable, and everything a designer does is a departure from it.

Putting the whole system together

A lighting system is the same shape as any other system in this trade: a decision travels down a chain until it becomes something an audience experiences.

A console holds the values and decides them. A data path — DMX over five-pin cable, or Art-Net or sACN over a network with a node converting back to DMX near the truss — carries them. Power, entirely separately, makes the fixtures alive, and the separation of those two paths is the single most important structural fact about a lighting rig. Dimmers sit in the power path for conventional fixtures, taking instructions from the data path. And fixtures at the end listen at their addresses and make light.

Two paths, not one. This is why a fixture can be receiving perfect data and be dark, and why another can be fully powered and ignore everything you do. Every fault you will meet is in one path or the other, and the first question in any diagnosis is which.

On a real job the order of work follows from this. The rig is hung and pointed, which is rigging and is usually somebody else's qualification. Power is distributed and proven. Data is run, terminated, and proven fixture by fixture. Addresses are set and written down. The console is patched to match. Then, and only then, focus — pointing and shaping each fixture where it needs to go, which is slow, physical, and the part that most determines whether the show looks good. And then programming, which is the part everybody imagines the job to be and which is perhaps a fifth of the time.

The last thing worth saying is about what the job actually is. A rig that works is the minimum, and it is not what gets somebody booked again. What gets you booked is being the person who noticed the shadow falling on the screen, who asked what the camera was white-balanced to before anybody thought to, who wrote down the address change so the next person was not misled. Lighting has a large aesthetic component and a much larger reliability component, and the second one is entirely within your control from your first day.

The four functions of light

Ask which one each fixture in your rig is serving. Anything serving none of them is decoration, which is fine as a decision and bad as an accident.

The positions, and what each one is for

Five angles. Between them they explain almost every stage you will ever look at, good or bad.

On the job

A charity gala. A stage six metres wide, a house rig of eight conventionals on a front bar, four LED washes on the floor for the backdrop, and a client who wants it to "feel special" on a budget with nothing left in it.

The stage as found is front light only, at full, with the LED washes making the backdrop a strong blue. It is bright, it is even, and it looks like a lit meeting room with a blue wall.

Nothing needs to be hired. Run the four functions and the four properties. Visibility is more than covered — there is too much front light, not too little. Modelling is entirely absent, which is why faces look flat. Selective focus does not exist, because everything is at the same level. Mood is being carried entirely by the backdrop, which is doing it alone.

Three changes, all free. Take the front light down to around sixty percent, which immediately reduces the meeting-room feel and lets the backdrop read as colour rather than competing with it. Move two conventionals from the front bar to a position behind and above the lectern for back light, at maybe forty percent, which puts an edge on the speaker and lifts them off the blue. And take two of the remaining front units round to one side, so the light on the lectern arrives at an angle rather than straight on.

The result is dimmer than what was there and looks considerably more expensive. What changed was position and contrast, which cost nothing — and the only thing to watch is that the new back light is not spilling into the first three rows or onto the screen, which is worth checking from those seats rather than from the desk.

How to do it

Lighting a speaker from nothing, with limited fixtures. This is the functional baseline, not a style, and it will make almost any stage acceptable.

1. Decide where the person will actually stand, and mark it. Every angle below is measured from that spot, and a stage lit for the wrong position is lit for nobody.
2. Put a key in first, from the front at roughly forty-five degrees to one side and forty-five degrees up. Look at the face. You should be able to see it clearly and see shape in it.
3. Add fill from the other side at a lower level — enough to open the shadow so it is not black, not so much that it disappears. If the face goes flat, you have gone too far.
4. Add back light from behind and above. Bring it up until the person separates from the background, then stop. This is usually lower than people expect.
5. Go and sit in the front row and check the back light is not in anybody's eyes, and look at the screen to check nothing is spilling onto it.
6. Light the background separately if you have fixtures left, so it is a deliberate colour rather than whatever happens to land on it.
7. Now check the four properties across the whole picture: enough light, right colour, right size, right position. Fix whichever is wrong, one at a time.
8. Look at it from three different seats before calling it done, including one at the side. A stage that only works from the middle does not work.

What goes wrong

Practice it

Seven questions. Most of them you answer by looking rather than by calculating, which is the point of the chapter.

Where to Go Next

Lighting is the department with the widest gap between where you start and where you can end up, and unusually for this industry the route is fairly clear. What you have here is the trunk; every direction below is a branch, and all of them start from the same understanding.

• If the console interested you most, go to Lighting Operation and then to console-specific training on whichever desk your market runs.
• If the rig interested you, go to rigging and electrics — a qualified trade, well paid, and always short of people.
• If the look interested you, go to The Art of Light and then towards lighting design, which is the long road and the one with no ceiling.
• If the moving lights interested you, go to Lighting Automation and the automated-fixture side, which is its own specialism.
• If the problem-solving interested you most, that instinct is worth more than any of the above. It is what makes a technician the person who gets called.

Choosing without guessing

Those are honest directions and they are not a decision. What decides whether a route suits you is more ordinary than the subject: how much of your week is travel, whether you would rather be judged on taste or on reliability, whether you like the show or the problem, and what you already have that you are discounting because it did not happen in AV.

Start with the Opportunity Map, at https://reboot-opportunity-map-v1.vercel.app, which draws the industry as a transit map and shows what is genuinely next to the station you are standing on. Somebody who can patch a rig and trace a dead fixture is closer to a lighting console than they usually believe. Looking around costs nothing and takes a few minutes, which is why it comes first: it is far easier to judge a route once you can see where it goes.

Then, if something on the map has your attention and you want to know whether it actually suits you, take the AV Pathfinder, at https://reboot-pathfinder.vercel.app. It is a short personal quiz, and what comes back is three AV paths that suit you with a Reboot course journey mapped to each — the specific courses, in order, between you and that path.

Both live inside the Reboot community, which is also where the rest of the course library sits, so you will be asked to sign in.

About Reboot AV

Reboot AV exists because the audiovisual industry has a map problem. The work is there, the pay is real, and the ceiling is high, but almost nobody entering it can see the route from where they are to where they want to be. People do not fail in this trade for lack of talent. They fail because nobody ever showed them what the path looked like.

So Reboot AV builds the thing that was missing: a course library covering the full breadth of live-event and installed audiovisual work, an interactive map of the roles in the industry and the routes between them, and an assessment that helps people work out where they actually fit rather than guessing.

Glossary

What the gear actually looks like

Every device named in this book, in one place. Recognition is the whole point of Chapter 4 — use this page to attach a picture to each name before you meet it on a dock at six in the morning.

Audio

Dynamic microphone

Condenser microphone

Wireless handheld

Radio rack

Mixing console

Stage box / snake

Power amplifier

Main loudspeaker

Subwoofer

Stage monitor wedge

In-ear monitors

DI box

Video

Camera

Video switcher

Scaler / processor

Projector

LED wall panel

Confidence monitor

Lighting & control

Conventional fixture

Moving-head fixture

Lighting console

Dimmer

Show controller

Media server

Networking & infrastructure

Network switch

Patch bay

Equipment rack

Power distribution

Cable tester

A properly coiled cable

Connectors, close up

XLR

TRS / TS ¼-inch

SDI on BNC

HDMI

Cat5e / Cat6 (RJ45)

Fiber optic

DMX (5-pin XLR)

AC power — not signal