Stage and film: a fair exchange?

The Merchant of Venice was a hit at the National Theatre, but can it work as cinema? Its director, Trevor Nunn, tells James Rampton why he believes it will

The actress Derbhle Crotty is pacing nervously around the set at Pinewood Studios. She is preparing for her big set-piece speech as Portia in a film version of the National Theatre's acclaimed production of The Merchant of Venice. Suddenly, the director Trevor Nunn materialises at her side and puts his arm round her shoulder. Like a football manager urging on his team before a vital cup match, he is psyching her up for this key moment.

As he beckons the camera in towards her face, Nunn whispers in her ear, "Right, this is the one." Dressed in a scruffy denim outfit, he barks "action", and Crotty delivers the speech to camera with a quiet yet undeniable intensity. For the director, it is mission accomplished. This canny psychological boosting of an actor before a close-up is known in the trade as being "Trev'ed".

It is just one of many film-making tricks that Nunn has up his sleeve. Over the past four decades, he has compiled such a peerless theatrical CV that he might have acquired the boxing-style moniker of Trevor "Second To" Nunn. There must certainly be precious little space left on his mantelpiece after the awards he has picked up for such lauded productions as Cats, Sunset Boulevard, Summerfolk, Troilus and Cressida and My Fair Lady.

But what is less well known is that during the same period, Nunn has also accumulated a formidable body of work as a film-maker. His films of Oklahoma!, The Comedy of Errors, Macbeth, The Three Sisters, Othello and Porgy and Bess have won critical plaudits, while his screen version of Nicholas Nickleby scooped an Emmy Award.

He would be the first to admit, however, that before embarking on a film adaptation of a successful stage-play, it is best to purge yourself of all memories of its theatrical origins. It is essential to start a movie with a clean slate.

Look, for instance, at the panache with which director Baz Luhrmann spiralled off from the original play to create a fresh and vibrant movie with William Shakespeare's Romeo + Juliet. In the same way, Nunn's filmic reading of The Merchant of Venice achieves a critical balancing act; it is dramatic, without being stagey. It is a film in its own right.

After the filming has been completed at Pinewood, Nunn is unwinding in his splendid office overlooking the Thames at the National Theatre, where he has had a sometimes turbulent reign as director since 1997. Dressed in the same distressed denim shirt, he has the compelling air of a passionate, if occasionally somewhat absent-minded professor.

He recalls how he first formulated his theories about filming theatre shows. "The first stage-to-screen project that I ever undertook was Antony and Cleopatra for the late, great Lew Grade in the 1970s," Nunn remembers. "He said, 'we'll just need to put four cameras in the auditorium and shoot the production a couple of times.'

"But I said, 'no, I don't want to work that way. The trick is to make a completely new piece of work while preserving the essence of the old piece of work. What you're buying is a wonderful group of actors who know their lines, but you can't buy the physical circumstances of the play's presentation. You have to let us work in three dimensions and make a piece specifically for a television audience. There is no other way.'

"In response, Lew called me to a meeting at 6.30 in the morning – only Lew, his cigar, his cleaner and I were there. He told me he was going with my idea for Antony and Cleopatra, and the film subsequently won a Bafta."

Nunn has been putting these ideas into practice ever since. He remains adamant that theatre productions have to be reworked for the screen – otherwise viewers simply end up feeling short-changed. "What puts television audiences off theatre for life is placing cameras in the auditorium," he asserts. "Theatre works as a live collective experience, and the power of the audience and the actors in the same room makes it the most potent possible form of entertainment. But you can't capture that on celluloid, you can't make that a real experience for someone watching a TV screen. That's why you have to provide something different for the television viewer."

The producer/director Chris Hunt, who has collaborated with Nunn on the Emmy Award-winning film of Oklahoma! and now on The Merchant of Venice, underlines the risks inherent in committing a stage production to film. According to Hunt, "if you just plonk cameras on stage, it looks stagey. The frames aren't composed with a film in mind, and the cameras have to grab the actors wherever they happen to be. It's horribly compromised and artificial; the viewer feels like an interloper.

"So when we start out making a film, we say: 'Forget the stage version, this is an entirely separate entity.' The simple distinction is: if the camera is where you want it to be, then you've got a film. You can't be in control in a theatre, because if you're using two cameras at the side of the stage, then one camera is always in the back of the shot. On a film, we cover every exchange with three strategically placed cameras in a studio. Crucially, we can then build up a story using the specific film grammar of editing. That's much more satisfying, because the audience feel the piece has been made especially for them. They don't feel like they're coming in on something made for someone else."

Hunt is not bothered that a studio-bound film often looks distinctly unrealistic – a charge sometimes levelled at the old BBC 2 Performance series. "Watching Singin' In the Rain, you don't give a damn that it's a bunch of Hollywood sets that don't look like real life. If the action draws you in, you just accept it. It's part of the suspension of disbelief. It's the same with this Merchant of Venice. If we get the emotions of the film right, then audiences will automatically get hooked by the drama."

The process of hooking audiences is helped a great deal by performances that are pitched at exactly the right level for television. Henry Goodman's mesmerising Shylock, for example, is speaking to a camera two feet away rather than the back of the dress circle.

"Working on film, I'm forever telling actors 'do less'," Nunn says. "I always try to find a positive reason why something that had been given full voice in the theatre should now be banked-down or why a previous urgency should now be hushed, rather than screamed. The net result on screen should be less facial movement and vocal stridency, but no loss of energy or detail or momentum." It demands the repressed emotion of, say, a Michael Caine as opposed to the flamboyant theatricality of a Laurence Olivier.

Paul Wheeler, the director of photography on The Merchant of Venice, takes up the theme: "Film requires an entirely different performance. If the actors gave it the power they need to reach the back row of the National Theatre when the frame-height is only slightly bigger than their face, then they would blow the tube out of the back of the TV set.

"The biggest difference lies in the framing. You never have a close-up in the theatre, but a film is 70 per cent close-up. So the whole emphasis of a performance is different, because we're choosing to take the audience up close and personal with the actors."

This film certainly captures all the strengths of the Olivier Award-winning stage production of The Merchant of Venice – a strong sense of time and place (Europe between the Wars) and cogently argued character motivation. But most of all, it tailors the outstanding stage performances specifically for film.

"For me, the most beautiful thing in the world is watching highly skilled actors at work," Wheeler declares. "That's what I live for – and that's what this film has in abundance. You can't get better than a National Theatre production of Shakespeare, can you?"

He pauses, before adding the one other factor that distinguishes this film: "And it's not a bad script, either, is it?"

'The Merchant of Venice' will be broadcast today on BBC2 at 2.35pm