Interior and Exterior Light as an Urban Context
Roland Kohr
When establishing night time lighting for the exterior of a building it is necessary to identify the distinguishing features of the environment experienced during the day. The nightscape doesn’t need to attempt to duplicate the daytime experience but it will take on an aesthetic quality of its own. By using lighting to identify the distinguishing features that are prominent during the day, the building is still identifiable as the same place whether it be seen night or day. As far as traditional buildings go, floodlighting directed onto the building from a concealed location is a suitable means or night lighting but now that more and more of our prominent buildings are becoming enveloped in glass skin rather than solid walls, light directed from the outside starts to become less viable. The night lighting of a building becomes a combination of both exterior illumination and interior lighting penetrating the outer skin of the building.
The approach to lighting a particular building should be based on its form as follows:
1. Solid Form?External floodlighting
2. Glazed Form?Interior Lighting
3. Mixed Form (combination of Solid and Glazed)?External and Internal lighting
4. Roof Form translucent/reflective?Internal lighting
Until the early 1900’s when the structural revolution of modernist architecture emerged, buildings were mostly solid, with apertures punched in the façade to admit daylight and fresh air. These apertures were originally known as wind-eyes from which the word window was derived. At night the buildings were experienced via interior light escaping through these uncurtained windows or by floodlighting from external sources.
The glazed form which was made possible by the structural revolution mentioned earlier is probably the simplest form of all. The entire façade is formed by the window which gives rise to an entirely different look at night than during day. The appearance during the day gives way to a “peep show” with the interior glowing with light. Different building uses maintain the need for different displays from behind the glass. Retail use would want to display wares where as office use might want to more privacy and implement opaque glass or blind to obscure the view but not limit the light show. The advantage of the easy view-in to a glazed building comes with the responsibility of ensuring that the view is worth looking at and not a view of back of filing cabinets or stacked up furniture. Dividing walls should not end in the middle of a window and mechanical rooms should not have a view.
The mixed form is a where areas of solid wall are counterbalanced by glazed areas. This form is developed from the functional needs of the plan and does not necessarily require the lighting of both glass from the inside and solid form from the outside.
An example of the roof form are the Buckminster Fuller geodesic domes of the 1950’s where the structures were formed of frameworks that permitlightweight translucent coverings. Other notable examples are the Millennium Dome, London, and the Pyramid at the Louvre, Paris.
Light as an urban context must include all types of light from office light to retail to residential. For our purpose residential is unnecessary to mention. At the pedestrian level the majority of architectural lighting comes from retail spaces. One basic rule that applies to the general lighting of shop windows is that the horizontal plane illuminates vertical surfaces. There are two ways of approaching street shop design. One way is to open up the shop front with large areas of glass allowing a panoramic view to the whole interior. The other way is the Chinese landscaping approach in which you block in the view, only allowing a small open area to reveal a limited prospect of the goods on display. Either luminance options can be attractive or detractive. Too much light can be over-stimulating giving the pedestrian too much to take in while too little can easily be ignored. Designers must take into account the lighting levels of surrounding buildings when forming their own designs at the street level.
Safety is an important factor that is determined at night by the level of lighting. While dark spaces can hide crime they also deter people from using those spaces. It is best to avoid creating walking paths that force people through dark spaces. Fitting into the context can mean lighting dark areas of surrounding building and therefore creating a more attractive place altogether. Parking garages can be difficult to illuminate fully. Steel structures allow thinner columns and greater view while concrete structures have thicker columns that can hide potential criminals.
Light from a building can have an effect on the natural environment by producing a luminous glow that impedes the view of the stars at night. Sky glow is the term used to refer to this effect. By obscuring the view of the stars, birds that rely on stars for navigation can become disoriented and lose their way. Residents living nearby can receive unwanted illumination when they need darkness, and thereby causing annoyance, distraction or even discomfort.
Lighting at the upper level of high rise buildings is what defines the building among its cityscape. Citizens often use identifiable buildings as landmarks when traveling those that inhabit the city are given a sense of place by the familiarity of the buildings that surround them. When individual facades that are suited for light experiments are transformed into a “luminous” theme, results can be quite alluring and pleasing to the eye. Cityscapes are not only defined by their appearance during the day but can also have a distinct characteristic of their own at night. Lighting can also be changed in accordance with the different seasons of the year, for example, green lighting for St. Patrick’s Day; green and red for Christmas, or red white and blue for the 4th of July. Lighting is one of the few aspects of a building that lacks permanence and therefore can more quickly evolve with the changing of a city’s mood or temperance. Local events can be given more appeal or show more support by the simple changing of bulbs in or outside of a particular building.
Bibliography:
Brandi, Ulrike, and Christoph Geissmar. Light for Cities Lighting Design for Urban Spaces, a Handbook. Boston: BirkhèAuser, 2007. 1-168.
The Outdoor Lighting Guide. New York, NY: Taylor & Francis, 2005. 1-379.
Phillips, Derek. The Lit Environment. Boston, MA: Architectural P, 2001. 1-192.