How a play is lit changes not only how it looks but how we feel about it. Top designers Paule Constable and Mark Henderson discuss mysteries of the craft

In the darkness of the Lyric theatre in Hammersmith, west London, an image shimmers in the distance. My eyes adjust: a playground, complete with child’s swing and climbing frame. The light is sickly, the colour of insomnia and sodium glare. The objects on stage have a menacing, hulking quality, as if they might be about to spring to life.

Beside me, Paule Constable whispers to a technician and there is a flurry of keystrokes. Gradually, the light intensifies yet somehow softens. Orange melts into rose-gold, then russet. The air in the auditorium feels warmer. I half-expect birds to sing. Illuminated by the glare of her laptop, Constable smiles. One miracle achieved, a scriptful still to go.

Even if you’re a regular theatregoer, when it comes to the art of lighting design you’re probably, well, in the dark. A favourite actor or director? Most of us could drop dozens of names. Many could pick out a set designer or two. But can you name a lighting designer, still less describe their work?

Facebook Twitter Pinterest ‘It’s like being a film editor’ … Paule Constable. Photograph: David Levene/The Guardian

That’s why Constable has been letting me tag along for a few weeks. An associate director at the National Theatre and winner of the Olivier award for best lighting four times, she’s one of the best in the business and has worked in theatre, opera and dance for the best part of three decades. The whizz-bang visuals of Curious Incident and War Horse are hers, and so was the chilly yet elegant illumination of the RSC’s Wolf Hall.

When we meet at the National, where she is working on the upcoming revival of Angels in America, I ask her the big question: what do lighting designers do? “It is hard to describe,” she says. “Someone at a major opera house I won’t name used to query how much lighting designers were paid, because surely all we did was turn the lights on and off.” She rolls her eyes. “It’s not even as if we get paid that much.”

Facebook Twitter Pinterest Chilly elegance … Paule Constable created the lighting for the RSC’s Wolf Hall, with Ben Miles as Thomas Cromwell and Lydia Leonard as Anne Boleyn. Photograph: Tristram Kenton/The Guardian

How would she describe the job? “I’m helping control the look of the show, but also telling the story. You create rhythm, pace, move the audience’s focus, control the frame, cut between long shots and close-ups. People often talk about painting with light, but I see it as more active: it’s like being a film editor, in a way.”

Although there are relatively few full-time lighting designers, there are many approaches. Some set designers or directors control their own light, or employ a technician who implements their instructions. Others, like Constable, see themselves as collaborative creatives, whose job it is to help conjure the whole world of a show. Anyone who watched Curious Incident’s Christopher drift across stage in a blizzard of stars, or recalls the dramatic battlefield chiaroscuros of War Horse, will know there’s far more to lighting than making sure Macbeth looks dreary or the opening of The Cherry Orchard feels early summery (both, Constable tells me, are challenging).

Once the set is built, and the lights hired, Constable goes to work on “plotting”, providing a rough cue chart of lighting changes for discussion with the creative team. Does a scene require daylight – and if so, what time of day and year, and is it filtered through a window? Are there “real” sources on stage (a table lamp, a wall fitting), or is light less literal, more emotive? Do individual performers need follow-spotlights, or need to be “cheated” out of the background by subtle varying of brightness? Should the audience be conscious of effects such as a sudden blackout or powerful splash of floodlight, or do these need to be imperceptible?

Facebook Twitter Pinterest Paule Constable’s latest show is Seventeen at the Lyric, Hammersmith, London with Roger Sloman as Tom and Diana Hardcastle as Jess. Photograph: Tristram Kenton/The Guardian

Every time a light is turned on or off, or its intensity adjusted, it must be programmed. Even though the Lyric Hammersmith show Seventeen, by Australian writer Matthew Whittet, is extremely straightforward, there are 32 cues, nearly all of which should be too subtle to notice. A big West End show might have thousands.

Technology helps. It’s hard to think of another branch of theatre where things have changed so much, or so rapidly. A century ago, spectators were still getting used to the new-fangled technology of electric light, first introduced at London’s Savoy theatre in 1881. Producer Richard D’Oyly Carte extolled the benefits not only in “enjoyment” and visibility but in safety – gas lighting, which theatres had relied on for the previous 80-odd years, was notoriously dangerous and foul-smelling. Candles, used in secular drama since the middle ages, were even riskier, evidenced by the fires that destroyed countless 18th-century theatres.

Although the introduction of calcium-oxide “limelight” – high-intensity spotlighting – in the late 1830s gave producers more flexibility (actors were understandably enthusiastic), it wasn’t until the 1950s that lighting systems became complex enough to offer artistic possibilities beyond an even “wash” that made the set and actors visible. The Strand lighting company was an early pioneer, commissioning an organ-like lighting console in 1935, complete with keyboard, that could be “played” by the operator. It was still being used at the Theatre Royal, Drury Lane in 1977.

Seventeen review – veteran actors get teenage kicks in striking portrait of youth Read more

Mark Henderson, a six-time Olivier winner who worked on The History Boys and Jonathan Kent’s Gypsy revival, says that despite a background in stage electrics, even he is baffled by the pace of change. “When I started, you had a console with some faders and perhaps a couple of channels. Now you’re free to animate, create amazing patterns, incredible colour variations. It’s almost infinite.”

Digital desks capable of memorising vast lighting grids and thousands of preset combinations were a huge leap forward in the 80s, followed by “intelligent” motorised spotlights and a byzantine variety of light sources offering different qualities and colour temperatures (tungsten, sodium, halogens, high-intensity discharge lamps). In the past five years, low-energy LEDs have been revolutionary, enabling designers to mix colours within the light itself rather than rely on “gels” attached to the front. As elsewhere, the music industry led the field: there is a reason why many musicals now boast enough candlepower to power a stadium gig.

Even so, Constable says that sometimes less is more. “I try to use as little as I can, as much for reasons of sustainability as anything else. But then everyone always says my stuff is underlit!”

She is full of praise for the experiments being conducted at the Sam Wanamaker auditorium at Shakespeare’s Globe, painstakingly modelled on 17th-century playhouses, where candlelight is used. “It’s just so powerful – dark and rich. And it makes you realise how valuable light is. It’s one of the most precious commodities we have.”

Facebook Twitter Pinterest Tia Bannon as Perdita and Steffan Donnelly as Florizel in The Winter’s Tale at Sam Wanamaker Playhouse, London, where candles replace electric stage lighting. Photograph: Tristram Kenton/The Guardian

Speaking of the Globe, what did she make of the furore over artistic director Emma Rice, who announced her resignation last October, six months after taking the helm? The controversy, bizarrely, was to do with lighting – Rice’s decision to use artificial lights and sound in the outdoor Globe, which scholars decried as “inauthentic”.

Constable scoffs at the dispute: “We’re reinterpreting the space for contemporary audiences. The lights Emma used weren’t permanent. And there are floodlights there, anyway, because it’s often too dark in the evenings. The whole thing just felt very luddite.”

I ask Henderson whether the discipline attracts obsessives. “Oh, there are loads of geeks, especially on the technical side. It used to be a thing to look at a colour on stage and identify the code of the gel, L202 or whatever.” He admits he finds it hard to go to the theatre and not concentrate on what’s happening lighting-wise: “It’s a bit of a pity, really, but you find your eye wandering up to the lighting rig, wondering what they’ve done.”

How about Constable; is she able to switch off? She laughs. “Friends are always asking me to look at the lighting in their house. I tell them they should be careful what they wish for: I’ll turn everything down and make it impossible to see.”

I wonder if it bothers either of them that, despite all these efforts, many people won’t notice what they do. Constable insists not: “It’s almost subversive. You can make a show feel different simply by adjusting how it looks, and barely anyone will realise why.”

Henderson seems even more relaxed. “It doesn’t bother me in the slightest.” He laughs. “It’s ironic, really – your job is to be invisible, in a way.”

• Seventeen is at the Lyric Hammersmith, London, until 8 April.