The Arup Lighting group has continued to develop its reputation in the field of couture retail lighting by recently completing a lighting design scheme for the new flagship Prada store in Tokyo. Working with architects Herzog & de Meuron, and in close collaboration with the client, Arup Lighting's latest project promises to be a visual success.

The Prada store in the fashionable Aoyama district of Tokyo is the first to be newly built specifically for the design house. At seven storeys high, the unusually shaped building has a striking presence and is on a site with an open plaza space in front of the main entrance.

On the facade, some of the glazing elements are convex, so that one feels that the inside of the building is looking out at you, others are flat, and some are concave that appear to draw you into the building. The overall concept is that the entire building is part of the shopping experience. The building is well day-lit because of the unshaded glazed facade. The floor layouts have been designed with the likely distribution of daylight in mind with complementing levels of ambient electric lighting to improve the lighting for the merchandise in general. There is also an adjustable lighting system for highlighting the merchandise display items, such as mannequins and display tables.

The architecture inspired a simple lighting solution. Suspended lighting fixtures through a perforated metal ceiling not only give good direct lighting to the floor but also highlight the ceiling material with a 'halo' of light around each fixture.

There is a certain randomness in the lighting scheme that suits the unusually shaped floor plan. On average, the spacing of the downlights is kept constant, but the layout is irregular. The spotlights are positioned with maximising the flexibility of the display in mind, rather than conforming to a regular pattern in the ceiling. As well as the appropriate aesthetic of this type of layout, there was a functional advantage as well - it made coordination with the structure and mechanical equipment in the ceiling much simpler.

A key feature of the lighting scheme is the lighting of the three vertical cores that run the full height of the building. There are integrated shelves that are effectively part of the face of the core and they are lit by concealed cold cathode lighting, with additional lighting of the cores provided by spots in the ceiling. The overall effect being that at night, when the shop is closed, the three cores remain illuminated along their full heights to express the structure and form of the building. This night-time view has been carefully considered, and planned in conjunction with a number of abstract video projections at various locations. This ensures that the building is a landmark at all times.

To further entice and attract the clientele, the main entrance is surrounded by an illuminated 'halo' which is an extension of the diamond grid that forms the facade. All the display tables and seating are also self-illuminated. They are made of a textured translucent material (fibre reinforced polyester) and most are illuminated from within using fluorescent lighting, to create a subtle glow. A few stand out by being illuminated by strings of side-emitting fibre optic cables, creating an organic, jellyfish-like effect.

The final key element of the electric lighting is for the more intimate spaces - in particular, the three horizontal structural 'tubes' between some of the floors. Inside these, the main fitting rooms are located. These spaces are illuminated to more intimate lighting levels and have a warmer feel. Warm-coloured compact fluorescent lamps are recessed in the wall, mounted behind custom-made silicone diffusers. The layout of these is based on the functions of the space - with circulation and storage areas having a little less light, while the changing rooms themselves have more.

Andrew Sedgwick, Arup Lighting project director commented: "We realise the importance of and are inspired by exemplary visual presentation. As lighting designers we couldn't be more delighted to work on this vibrant and exciting project in the company of such creative thinkers - it's been a worthy challenge and a pleasure."

technical information

Architects: Herzog & de Meuron
Lighting Design: Arup Lighting
Lighting Supplier: Lighting System Co. Ltd
Lighting Solutions: Ceiling fixtures - Interlux; 'Tube' spaces - Solx, Modular; fibre optics - Philips; Cold cathode - SystemInte Okamura; floodlights, recessed downlights in back-of-house - Maxray; fluorescents and controls - Matsushita.

information: www.arup.com