REVEALED IN LIGHT.

Shaped by latitude, culture and place, the capacity of light to make manifest built form and move the human spirit has been a richly poetic element of architecture since the earliest times. Contemporary fascination with achieving both material and spatial ephemerality continues and extends this immemorial relationship with light.

Architecture depends on light. As light reveals the forms of architecture and the places made by it, it simultaneously manifests the meaning and intentions inherent in the processes of conception and building. Such meanings are both particular and universal. Architects and artists have long been aware of the potential of light to move the human spirit. From earliest times, light has been consciously sought out for its expressive and numinous power. Sunlight described sculptural reliefs on temple walls, filtered through colonnades, illuminated the interiors of basilica halls and sparkled off mosaics. Light radiated through the gorgeous stained glass of medieval cathedrals and glimmered in arcaded loggias. It diffused softly through Japanese shoji screens and was veiled by intricately carved mashrabiyyas, casting arabesque shadows on walls and floors.

Humans are phototropically inclined, so illuminated places set in darkness exert a powerful attraction. The upward pull of a starry cupola or the mesmerizing allure of a sun-drenched atrium are some obvious examples. In the Baroque period, painters such as Caravaggio and Rembrandt explored the tenebrous effects of shadow and light to dramatize the essence of human struggle and sanctity. In Nordic stave churches, the mystery of the forest was fixed and explained as 'dark light'. Whether in painting, sculpture or architecture, light links the visual environment with human perceptions and sensitivities.

Light that is visible to the human eye occupies an extremely small part of the electromagnetic spectrum. This confluence of the visible spectrum, the structure of the human eye and entire perceptual system is in itself a miraculous synthesis. Within average sensitivity ranges to light and colour, each of us sees in a unique way and our cumulative experience of light in space is richly complex. Before the advent of electricity and its capacity to deliver 'delayed light', we were probably much more aware of our place in the universe. Starlight and moonlight defined the night, and through these natural phenomena, the remote and mysterious universe was a source of awe, fear and wonderment.

Through the modulating matrix of architecture, ethereal light can be transmuted into a tangible element of buildings, a space filling and defining presence. Among the most enduring ways of handling light, the oldest and most basic involves a fusion with matter. Trapping and reflecting light in mass impregnates forms with a radiant, vital energy. Tadao Ando's stark concrete walls, for instance, assume the remarkable potency of mass transformed by nature when animated by changing light. Methods of sensitizing solid material to light have been painstakingly cultivated and passed down through generations of builders and craftsmen. Opaque materials such as polished wood, ceramic tiles, silken plaster and the glass-sandwiched leaf of gold mosaic were transformed into glowing, lustrous lattices, catching and mirroring light. For baser materials, hewn and chiselled textures invested mass with a flickering play of light and shade. In this way, even the most drab substances could be induced to undulate and pulsate wit h life.

The nature of luminance varies enormously with latitude and landscape, generating a perpetually changing diorama. In equatorial regions, the intensity of light is so strong and shadows so short, that objects appear to vibrate and dissolve. In northern forests, light is filtered through clouds and foliage forming picturesque patterns of shadows, giving rise to romantic musings and dreams. As Henry Plummer observes in his lyrical essay on Nordic light (p70), place and culture determine our relationship with light, which is evocatively crystallized through architecture.

Christian Norberg-Schulz singles out the window as especially important in defining the spirit of place, 'It does not only express the structure of the building, but also how it is related to light'. The windows of the Netherlands, for instance, are as distinctive as Japanese shoji. The shoji cannot be comprehended as a single element that controls the quality of light, but form part of the pattern and rituals of traditional Japanese dwellings. Historically, Dutch windows are unusually large, to minimize the load of houses on waterlogged land. But in the Dutch climate with its colossal, cloud-filled skies, light is prized and windows tend to claim as much of the walls as possible. For Flemish artists such as de Hooch and Vermeer, this light was a profound source of inspiration. Vermeer's remarkable paintings, made in his studio facing the market square in Delft, capture a gentle luminance diffused through windows, shutters, curtains and draperies. Stealing quietly across rooms, the delicate light reinforces the gentleness and dignity of domestic life.

Contemporary use of translucent or semi-transparent glazing materials (such as frosted glass, translucent plastic sheeting, double layers of glass and perforated screens) expresses the current fascination for an architecture of material and spatial lightness. This continues the Modernist quest for talismanic transparency, but unlike the simple pristine clarity of a Miesian glass box, contemporary notions of transparency are more subtle and diffuse, as evinced by UN Studio's new art museum in Nijmegen (p54). Suspended within multiple layers of the building structure, the effect of this gauzy translucence is to elevate space into an experience of lightness and weightlessness. Such ephemeral architecture reflects the increasing sophistication of building technologies, but also manifests a persistent theme in the evolution of architecture.

Light acquires meaning in architecture as part of a sequence of luminous relationships. Light reveals the building, its intentions, its form, space and meaning, modulated by the consequences of place. As Christian Norberg-Schulz contends 'The study of light is something more than a mere investigation of illumination. Light and things belong together and every place has its light. The sky is the origin of light and the earth its manifestation. Always the same and always different, light reveals what is.' [*]

(*.) The Poetics of Light, A+U, December 1987 supplement, p7.