Wellcome Wing

Imagine the colour blue, that intense electric blue of a summer sky just after the sun has set. This is the colour that has inspired, preoccupied, frustrated and delighted architect MacCormac Jamieson Prichard and lighting design group Hollands Licht for the past four years. It is the colour that suffuses the Wellcome Wing, the new £48m extension currently under construction at London’s Science Museum. Blue will glow from its walls and drench the air with its hue, an effect that was as hard to achieve as it will be to ignore.

Architect Richard MacCormac’s response to the Science Museum’s brief for a flexible exhibition space to display the latest scientific and technological discoveries, was to create a stunning “theatre of science”. John Durant, Wellcome Wing project director, says the appointment committee was “struck by the power” of MacCormac’s concept of a big blue space with an Imax film theatre poised overhead, “like a spaceship landing” and the three exhibition floors invisibly suspended, “as if floating in an evening sky”.

Visitors will enter the wing from the east through the existing museum. The curving underbelly of the Imax theatre will slope vertiginously up and away, leading your eye towards the floating exhibition floors stepped back at the same angle. To either side, north and south, will be concrete partition walls washed with blue light while in front, to the west, will be a blue glass wall.

The deep blue space that surrounds you wherever you look was a clear enough image in Richard MacCormac’s mind, but achieving it was rather more complex. Lighting knight in shining armour, Rogier van der Heide of Hollands Licht became involved in the team almost by accident.

He came across the Science Museum website while surfing the Internet from his Amsterdam home, and read about the new wing. Being interested in science centres, and not one to pass up an opportunity, he called the next day and was given the architect’s number.

Within three days, van der Heide was in London bouncing ideas around with MacCormac. This was three years ago and very early on in the design process. “When we’re involved so early, we can make use of the dimensions of light and add to the architectural concept of the building rather than just specifying fittings,” said van der Heide. As it turned out, it was lucky he joined the team when he did.

The museum pointed out that a glowing blue box is all very well, but blue-hued people and objects could be stretching the theme just a little too far, and may even send visitors rather green around the gills. The lighting designers suggested a powerful white source on the exhibition areas to wipe out the blue. But according to the curator, valuable artefacts meant that 50 lux was the maximum. And so it began.

For the north and south walls, van der Heide explains that they wanted to achieve, “Something that goes beyond the physical boundaries of the architectureä a very deep blue space”. A scrim stretched taut on a metal frame in front of the concrete walls helps to achieve this appearance of depth. The scrim, like net curtains, allows you to partially see through the holes of the weave. The glass fibre fabric also catches the light and radiates it diffusely.

In between the scrim and the wall are light fittings emitting only 1 per cent of their potential output, a deep blue light of such a narrow bandwidth that the eye finds it difficult to focus. The lights are compact fluorescent lamps with special reflectors whose geometry allows the light to be washed across a wide area of wall (7sqm). The spread of light is overlapped to prevent shadows and so present an even, continuous wash of light over the surface of the walls.

At the same time, the reflectors keep the lamps’ beam at a very narrow angle within the 700mm gap between the wall and the scrim to keep the colour wash under control and prevent it spilling out into the exhibition space and colouring any objects or people in range. The lamps had to be purpose-made and there are 1500 in all, covering the north and south walls.

“The double effect of the uncomfortable colour of the blue light, and the thin layer of something that you can almost see through, but can’t, is very disorienting,” says van der Heide. “The result is that you see this scrim and you can’t judge what is behind it. There may be a wall or there may be infinite space.”

Even more complex was the blue glass west wall. “The sun is a big trouble-maker,” says van der Heide, adding that on a sunny summer’s day the light level through a window can reach

150 000 lux. To put this in context – to enable exhibition lighting at 50 lux to wash out the blue tinge, the sunlight penetrating the blue glass wall had to be reduced to 3 or 4 lux. “Controlling the sunlight was an absolute necessity,” van der Heide says. “But on the other hand, I really love the idea of having the dynamics and kinetic effect of natural light within a building, so I didn’t want to just block it all out.”

There were arguments for a dynamic louvre system that would change angle depending on the sun’s position, but this was dismissed because the visual effect is dull. “The sun’s effect is just flattened,” says van der Heide. “The highs and lows aren’t there anymore.” In the end they decided to use a number of layers to mitigate the sun’s brightness. The first is a perforated metal façade that immediately cuts out 40 per cent of the light.

The next step was to add a 6mm layer of clear float glass with a special coating that blocks heat transfer and ultraviolet radiation. The steel structure of the building constitutes the next layer, followed by a static louvre that was chosen for its ability to transform the sun’s rays into a diffuse light that has all the sun’s dynamic qualities, but none of its aggression. The louvre blocks out direct sunlight all through the year except for one moment, “It’s something like 4pm on 21 December,” van der Heide adds, “The sun almost peeps through and perhaps does for a few seconds, then the moment’s gone.”

The final layer, of course, is the blue glass. “It was a big challenge to find the right colour blue,” he says. Following extensive tests, calculations and full-scale modelling in Holland Licht’s Amsterdam studios, a body-tinted glass (as opposed to clear glass with a coating) was chosen because its thickness defines the saturation of the blue. In the end, a thickness of 8mm was deemed the right colour.

“After going through this whole assembly the light level is low enough to cast no blue light on the objects 6m away, but there is still a fascinating projection of the sun and all its dynamics,” van der Heide says.

The final lighting feature in the Wellcome Wing is the staircase. “We didn’t want to just make it a functional space,” he explains, “We wanted to continue the drama and the concept of the immersive environment.” The designers came up with a different interpretation of the same idea, which involved painting the tall, narrow staircase shaft deep blue. Scenic paint, of the sort used for painting sets in the West End, was specified for its super-saturated colour. “It doesn’t contain any chalk, it’s almost pure pigment,” according to van der Heide. “It’s extremely intense and very special.”

Each stair and landing is dramatically lit by halogen lamps suspended from the walkways above. Special reflectors in the lamps narrow the beam to about 6 degrees, thus creating concentrated pools of light, in spite of the long throw of 12m. The destination point of each walkway is lit with the bright glowing orange light that is at completely the opposite end of the spectrum to the blue, making for a very dramatic effect.

“Lighting the destination point like this is a very strong statement and makes the dark environment less scary,” says van der Heide. The designers are also considering lighting the elevators with the same orange, so that as the doors open, the orange glow will spill out into the dark blue space.

Doesn’t all this drama in the shell of the building make for a difficult job for the exhibition designers Chris Wilkinson Architects is responsible for the ground floor and Casson Mann, which is designing the upper floors. “This has never been done before, so we’re working in the dark rather,” says Paul Baker of Chris Wilkinson Architects. “But, as I understand it, there will be no rendering of blue in the exhibition areas, it’s very exciting and doesn’t prevent us doing our job. In fact it’s the exhibition designer’s dream of having a black box to light how we want.”

Roger Mann of Casson Mann is in favour of the wing’s lighting scheme as “museums are usually black boxes or daylit, and that’s boring”.

However, he admits that the consultancy was at first worried about the amount of blue used “as it makes the eye read other lights as warmer than they are. This means that white lights might appear yellow.”

Now, having seen the size of the space, he is less concerned. “If necessary, we’ll make our lights even colder to make them seem white. I think the overall effect will be amazing,” he adds.

The stage is set for completion in 2000 and Durant at the Wellcome Wing advises visitors to, “prepare themselves for the knockout moment of that breathtaking first view”.