Light box.

Conceived as part of a plan to reconfigure an existing square in Rotterdam, Koen van Velsen's new cinema reinterprets a traditional introverted typology as a dazzling celebration of material and visual lightness.

Formerly a run-down and depressing tract of urban space in the heart of Rotterdam, the Schouwburgplein is now an imaginatively revitalized city square (AR January 1998). Masterplanned by landscape architects West 8, the redevelopment programme encompasses new street furniture, landscaping and light sculptures, together with a new multiscreen cinema designed by Koen

van Velsen. On the west edge of the square, the new building manifests the resourceful spirit of the Schouwburgplein's reinvention. It also provides a new social and cultural focus for the area, which, historically, was the centre of Rotterdam's entertainment district.

The cinema is conceived as a free-standing box with the corners bevelled off, but its blind bulk has been transformed into an ethereal, translucent volume of great lightness and surprising delicacy by van Velsen's ingenious handling of the elevations. Wrapped around the great flanks of the exterior is a lightweight skin of corrugated opalescent polycarbonate sheets. At night, the entire building lights up like a huge, free-form Japanese paper lantern, glowing with a softly luminous intensity. Van Velsen's contemporary reinterpretation of a fundamentally introverted building type explores concepts of visual and material lightness, far removed from the historical notion of the cinema as a hulking, opaque bunker. Yet the unorthodox choice of cladding was as much dictated by function as appearance; the cinema sits on top of an underground car park, so the intention was to minimize the imposed load of the new building. The milky-white cladding stops short of the ground, so that the cinema appears to hover lightly on the edge of the Schouwburgplein, fluidly connecting with the urban landscape and anchoring the composition of the square.

The new building houses seven cinemas of varying sizes. The largest seats 700 people and the smallest 200; overall capacity is 2700. Volumes are arranged around a pivotal promenading and foyer space that extends over several storeys. Visitors enter a busy entrance and box office hall at ground level, and then ascend a sweeping, red-carpeted staircase to the piano nobile foyer spaces. From here, individual cinemas are reached by a network of stairs, escalators and walkways that criss-cross the foyer. Bold contemporary graphics and signage identify each cinema entrance.

Van Velsen treats the orthogonal cinemas as a series of interlocking, sculptural blocks, exploiting the different-sized volumes to create a kind of architectural and spatial nougat. Three of the smaller cinemas are half-buried below ground (their roofs form the piano nobile floor of the foyer space), while the four larger ones are hoisted above the foyer, their sloping undersides creating a spectacular, undulating ceiling. A key technical requirement of the programme was a high level of acoustic separation between the individual cinemas. This is achieved by means of wall cladding comprising several layers of plasterboard supported by a secondary steel structure. The secondary frame is connected to the main steel structure by means of rubber blocks to prevent acoustic leakage.

Equipped with seating and cafes, the elevated foyer spaces are open to the public at all times of day. Access is not conditional on buying a cinema ticket, so the foyers act as a convivial extension to the square, creating a framework for the unpredictable patterns and flows of urban life. White plaster walls, highly polished metal floors and finlike glass balustrades, heighten the qualities of lightness and reflection induced by the translucent walls, through which also filter evanescent, enigmatic views of the city.