The cold never bothered them anyway: how Frozen made musical magic

The set, costume, video and lighting designers of Disney's London production – now in its second year in the West End – break the ice about its frocks, crystals and astonishing effects

Christopher Oram , set and costume designer: The joy of the film is that it behaves like a classic fairytale but also bends all the rules. Frozen is subversive and that's why it's successful.

Finn Ross , video designer: I found the design of Elsa's magic in the film really beautiful. It's not just pretty sparkles in the air but very emotionally connected to her state of mind and the magic becomes an extension of her. Theatrically, I thought that could be ripe for the telling.

Samantha Barks prepares for her role as Elsa. Photograph: Marc Brenner

Neil Austin , lighting designer: Like on Harry Potter and the Cursed Child, here was a chance to catch the next generation of theatregoers. With Potter, a huge percentage of our first year's audience were first-time theatre bookers. This was another one of those moments – you want a first visit to the theatre to be special, you don't want to put anyone off!

Finn Ross: I’ve worked on Harry Potter, Curious Incident, Back to the Future … they’re all incredibly precious to people. For audiences this is almost the ultimate in their journey of Frozen fandom – it is seeing the thing that means a huge amount to them come to life. That's a privileged position to then occupy as a designer and a significant responsibility.

Stephanie McKeon as Anna; hair and makeup backstage. Photographs: Marc Brenner

Christopher Oram: You’re trying to bring a new energy and life to it yet remain faithful to the world people are expecting. So the silhouettes remain the same but the details are different. You want to make sure that Elsa is in a long gorgeous blue gown. The dress that Samantha Barks wears is actually very little like the one that the animated character has but it passes what I call the squint test. It's a very different garment, designed to function in different ways. Snow was the elephant in the room. Frozen is entirely about snow … and snow is an entirely impractical thing on stage.

Finn Ross: We went through a massive process of characterising ice into different emotions – happy ice, sad ice, anxious ice, joyful ice. Now, when I look at ice, I can't help but anthropomorphise it! But in Elsa's world, it's not just frozen water – it's a product of her and represents how she feels.

Ashley Birchall (Sven) and Obioma Ugoala (Kristoff) on the bridge made for the London production; Scandinavian influences in the bedding and the girls’ costumes. Photographs: Johan Persson/Disney and Marc Brenner

Neil Austin: With lighting your influences can be more emotional rather than from the real world. Christopher took his influence from Scandinavia. There's a certain amount of Hammershøi (design) in the very cold and very dark scenes but it's so much more to do with the emotions of the music and the drama of the words.

Christopher Oram: The frame around the stage is based on Norwegian wooden architecture. There are carvings of scenes from the story of Frozen as well as other Disney shows including The Lion King and Aladdin – that's part of a Disney tradition of placing "hidden Mickeys" in their theme parks and movies.

‘We went through a massive process of characterising ice into different emotions.’ Photographs: Marc Brenner

Finn Ross: Transformation is a big theme in the show. At its most simple level that might be changing from stone to ice. Chris and Richard Nutbourne, the scenic artist, came up with a method of painting the "ice legs" so that under normal theatrical lights they look like stone but when you activate the LED lights inside them, it looks like ice.

Samantha Barks (Elsa) and cast in the castle. Photograph: Johan Persson/Disney

Christopher Oram: Like a lot of Shakespeare plays, the story opens in one place and then goes to a wilderness where the characters find themselves – like the Forest of Arden in As You Like It or Illyria in Twelfth Night. We go from a space that encloses you – the heavy wooden architecture of a candlelit castle – to one that releases you. We didn't want the castle to be too oppressive – there's a softness and a lot of colour in the rosemaling, which is a Norwegian style of painting floral motifs on woodwork. The windows in the girls’ bedrooms let you see the mountains outside and the aurora borealis. It gives you a sense of what's to come. We found a colour for the floor that meant it could be a marble floor in the castle as well as a frozen tundra.

Finn Ross: With Frozen it would be very easy to make an entire evening that's just blue. You don't want to do that – it's boring for the audience. So I went through each scene and came up with a colour journey for the ice to go through including purples, cyans, greens. The sunrise at the end of Let It Go brings a pink tone into the room. You want something that looks natural and fantastical at the same time.

The aurora borealis features in the video design. Photograph: Johan Persson/Disney

Neil Austin: The role of lighting designer is a mixture of roles – such as, from the film world, gaffer, director of photography, colourist and editor. The audience sits there with a wide shot for the entire show. It's up to the lighting design to pull your focus in, out or across the stage. The public's impression of lighting is that it is illumination but in fact, like a painter with chiaroscuro, what's way more important is where the shadows are falling and how that can make the picture as dynamic as possible. In Let It Go, those shadows allow us to hide or help obscure, drawing attention away from how Elsa's dress is going to change.

Christopher Oram: The Let It Go sequence was a mountain to climb. A lot of very brilliant people above, below and to the side of the stage make it happen. That's the thrill of making theatre. We have physics and gravity and budgets that we have to think about for the stage, that's different to animation. We had to be practical but deliver something visually astonishing. Everyone pulls together to make a moment of triumphant release.

‘A mountain to climb’ … Let It Go reaches its climax. Photograph: Johan Persson/Disney

Finn Ross: Let It Go has to build, build and build and then, when you think it can't go any further, find a whole new level to go to. It's a very giddy four minutes. This is a Disney musical – so go big or go home. You have such a big chunk of time and such resources, it's a great opportunity to push the medium forward and take a few risks.

Christopher Oram: Elsa's palace has a full-on Swarovski crystal curtain which has fantastic ability to sparkle and shimmer. Swarovski built it from our design. It has a floral pattern reminiscent of the rosemaling in the castle from Elsa's childhood.

Finn Ross: Upstage there is a giant LED wall with a 3.9mm pixel pitch. The colour rendition is incredibly rich and gives you a lot of depth. Once you commit to having a giant LED wall up there for the entire evening it becomes a kind of beast to feed but that's a fun job to take on.

Stephanie McKeon (Anna) and Oliver Ormson (Hans). Photograph: Johan Persson/Disney

Neil Austin: Before the "open up the gate!" moment I dragged down the light levels beforehand to adjust the audience's eyes to the darkness. Then Finn has a really lovely bright image on that LED screen. It's a metaphorical opening up as well as the light coming in – you want the audience to feel that joy of sunlight coming through.

Finn Ross: Video design is incredibly intersectional – you collaborate closely with the set designer in the early stages of the show and then, when you’re in the theatre, you collaborate closely with the lighting designer, too. Video designers take prerecorded or live video content and integrate it into the scenography, dramaturgy and flow of a show be that via projection on LED screens, TV screens or using cameras. We build that into a living, breathing design. The video department will put together a visualisation of the design and take that to the wider team for further conversation. Then when you put it on stage you can realise it's all wrong and needs changing because you’re feeling it in space as well as time.

Craig Gallivan (Olaf) performs In Summer. Photograph: Johan Persson/Disney

Neil Austin: In Summer is a crazy little moment of vaudeville in the middle of the narrative where you step into the internal world of Olaf – it's one of my favourite numbers.

Christopher Oram: There were a lot of problems to solve so you surround yourself with amazing people – like Finn, Neil and Michael Curry, the puppet designer. They all bring their expertise to the table. And you rely on the performer to animate the puppet. Craig Gallivan has such a good relationship with the puppet – it's both an extension of him and its own individual character."

Christopher Oram: A sense of unity and harmony comes from one person designing both sets and costumes. Wolf Hall [which Oram designed for the RSC] was a huge costume show – we needed a neutral scenic space to tell the story visually through the costume.

Whiteout. Photograph: Johan Persson/Disney

Frozen is a place where costume and set really tell the story together. It's not without some irony that Frozen is also pretty hot for the actors. In the whiteout at the end, they wear costumes that need to look thick and woolly but there's also a huge physical dance sequence so we had to find fabrics that appear heavier than they are and slice bits out so they weren't impractical to dance in.

Obioma Ugoala (Kristoff) backstage. Photograph: Marc Brenner

Finn Ross: Some of the technology used in the UK production is very different to the Broadway production and there's only a couple of years between them – that shows the significant developments that have been made. The systems and tools we use are designed to repeat exactly the same without variation. The video effects all run to timecode – with that much scenery moving around, from a pure safety point of view for the performer, you need precision. It also means every audience receives the same sort of quality of show.

Neil Austin: The invention of blue LED lights and colour-changing technology totally transformed theatre lighting. There's lower power draw and also, artistically, the choices have widened. All these LED units change colour and you can do that from the lighting deck, remotely.

Christopher Oram: The stage in London is twice as deep as our theatre in New York so we have room to store the big bridge upstage. The staircase in the palace was also something we built new for London. The additional space we have means it's not so chaotic – the whole wardrobe village is at the back of the stage so no one has to run up five flights of stairs to get changed.

Backstage at Drury Lane. Photographs: Marc Brenner

Neil Austin: The refurbishment at Drury Lane is amazing – not just what you see as the audience but also backstage. They spent a lot of money on a new grid, new dimmers, new infrastructure.

Christopher Oram: The Theatre Royal Drury Lane has a sense of grandeur and royalty that lends itself to the story, even the colours in the auditorium are sympathetic to the ones on stage.

An ovation for the cast onstage. Photograph: Marc Brenner

Neil Austin: You have a responsibility to ensure that everybody is seeing a good show. In previews you go and watch from the cheapest, most obscured seats at the back of the balcony to check that everything's fine from there. You sit and watch it with an audience and realise what you missed. You check whether you are storytelling which is what we all are – every design department, yes, has a technical and artistic discipline – but we’re all storytellers.

Frozen is booking at Theatre Royal Drury Lane, London, until March 2023.