The Sage Gateshead is Foster and Partner's first building for the performance arts and is one of the centrepieces of Gateshead Quays, a major arts, leisure and residential quarter. The £70 million project is also lauded for having the best acoustic performance in the world. But what about the lighting? Nick MacLiammoir of Equation Lighting Design Ltd, lighting designers for the project, explains all...

We began to design The Sage at the tail end of last century. Over the past five years a number of people have been involved however, for the last three years it was my project. Looking at it now I wonder at where the time went. It is really so simple, and yet, to achieve that simplicity and elegance required a huge investment in the detail of matching the lighting to the building form. Many buildings, maybe most buildings, can be understood in two dimensions. Not so with The Sage. It must be understood in three dimensions and every straight line related to the curve that springs from it. Even before the forms themselves one has to grasp that while it can be viewed as one building, it can equally be viewed as three buildings intricately linked and covered. Each of the halls has a very distinct character internally and yet externally they appear to be carved from the same block of stone, naturally, like the mesas of the Arizona desert, divided by canyons and gulches.

Conceptually our design for the presentation of the building is predicated on the play between the two 'external' facades, the outer shell and the halls. In terms of distant views we picked out the curve of the roof to the east and west with projectors, Sill and Bega, mounted on the line of the internal stairs and below ground level at the entrance. These curves relate the building to the bridges on the Tyne, new and old. However, the key to the external presentation is the treatment of the halls. Illuminating the internal buildings draws the eye through the shell. Rather than light the walls we concentrated the lighting on the soffits of the balconies with a fluorescent uplight softened with an opal diffuser. From a distance, and this building is always viewed from below, the bands of light read as a series of verticals expressing the massing. Just as importantly by reducing the actual illumination on the vertical surfaces to a minimum we preserve the night time views out of the building by minimising reflections in the glazing.

The challenge of the concourse, the internal/external public space, is that it must operate both as a grand area of traffic and movement and yet must contain comfortable, human scale areas that are warm and inviting; the bars, cafe, restaurant and box office. During the day the glazed facades allow the front of the concourse to be entirely daylit however the stairs between the halls require reinforcement to prevent them becoming gloomy. Good daylight reinforcement should appear quite diffuse and yet allow a degree of modelling. We created two lighting layers to achieve this. The base layer is diffuse lighting from fluorescents mounted on the hall roofs bouncing light off the inside of the shell. Added to that is a layer of highlights onto the stairs and congregation areas. These are provided by narrow beam, Sill CDM-T projectors, again mounted on the hall roofs but bounced off aluminium reflector panels hung from the structural steels. Each reflector has up to three projectors bouncing off it, often to different areas depending upon the projector location. Over many hours with a team of abseilers we focussed all of the projector/reflector combinations to create a web of beams picking out key routes and areas. The beauty of the reflected light is that it is controlled, directional but very soft. In particular, on the stairs it gave a clear contrast pattern between tread and riser that is important for visually impaired users. Of course, by mounting the fittings on the hall roofs we achieved two objectives, easy, safe maintenance, and light without visible light fittings. Under the balconies simple downlighting creates the focus on the box office and cloakrooms with the diffuse light coming from the fluorescent detail uplighting the balcony soffits. In the event we found that the combination of the uplights to the balconies and the projectors created sufficient illumination within the concourse to allow us to colour the fluorescents uplighting the shell with blue filter. We had been discussing the use of monochromatic blue light for a few years and found that it softened the presentation of the shell and, of course, created a greater sense of warmth and focus at floor level, so we kept it.

Each of the halls is quite different in feel, character and function, each contains the same attention to detail and yet there is something about the main auditorium, Hall 1, which still takes my breath away. I spent fifteen years as a theatre lighting designer and I cannot think of a more beautiful auditorium. It does not feel like a 1700 seat concert hall, it is so much more intimate. The surfaces are soft, light wood and there are no sharp edges to stop or catch the eye. Our approach to lighting was based on two simple precepts, rigorously separate the different surfaces, and work sympathetically with the quality of the finishes. Separating the elements allowed us to play with the presentation of the space for different musical forms. Working with the surfaces meant choosing sources that would accentuate the warmth and intimacy of the space. Over the seating areas a mixture of Erco tungsten halogen darklight downlights were used to provide ambient lighting from a range of mounting heights without lighting the walls. The walls are illuminated by dimmable fluorescent fittings housed in a detail developed with Foster & Partners which allows a degree of direct illumination on the floor via oval slots in the base and an opal diffuser. This allows the detail to both wash the walls and to provide emergency escape lighting. Regular travellers on the old GNER stock may recognise the derivation of this detail. Devising a mock up to measure and prove the emergency lighting from this detail over a range of mounting heights was one of the many interesting challenges that punctuated my three years. The heart of the presentation is the lighting to the balcony fronts. With Crescent Lighting and Agabekov we developed a linear xenon detail in a housing which cantilevers off the balconies and provides a warm wash to the oval tiers. By carefully controlling the section we optimised the wash without the lamps becoming visible. The piece de resistance is the acoustic baffles. Taking a similar xenon detail hung below the baffles the softly lit curves float in space and create real drama and excitement as the light moves with them.

Hall 2 is much smaller and more intense. Again we employed the principal of separating the elements. The red lacquered wood panels are picked out by ERCO wall washers with red filters. The balcony fronts are lit with xenon; small holes drilled in the underside of the housing give an added sparkle. Erco darklight downlights illuminate the seating. The black and red creates a furnace atmosphere, full of energy.

The rehearsal hall is the simplest, with light wood walls and black drapes to give two different presentations. Similarly the lighting mixes Concord:marlin Torus fittings, CDM-T for rehearsal use with a grid of tungsten halogen fittings for performance. The tungsten fittings can be controlled by six manual dimmers, zoned to allow for different seating configurations. Whilst this is the simplest lighting installation in the building we probably spent more time coordinating these fittings than any others.

Doing simple well is often quite difficult...

All interior photography by nigel young/foster and partners