E Guide Basics The Guide provides extensive information on topics ranging from the physical basics of light- ing through to possible solutions for specific lighting situations – in short, a veritable encyclo- paedia of architectural lighting. The knowledge modules make use of the interactive possibilities offered by the Internet, e.g. for Designing with light illustrating time-dependent phe- nomena, experiments or contrasts between alternative solutions: www.erco.com/guide Indoor lighting Outdoor lighting Lighting control Lighting technology Simulation and calculation Glossary Edition: 20/03/2007 | Updated version at www.erco.com 1 E Guide Basics It is inadequate simply to portray the eye as an optical system when describing human perception. It also needs to be explained how the image is interpreted. Both the perceptual psychology and the objects of perception are impor- History Seeing and percep- tant factors in understanding tion lighting design. Edition: 20/03/2007 | Updated version at www.erco.com 2 E Guide Basics History Right up until the 18th century people only had two light sources at their disposal: natural daylight and the flame – the latter being the only artificial light source since the Stone Age. These two types of lighting dictated the Quantitative lighting Qualitative lighting Perception-orientated patterns of life and architecture design design lighting design down through the ages, but a new epoch was ushered in with the invention of gas lighting and then electric lighting. Edition: 20/03/2007 | Updated version at www.erco.com 3 E Guide Basics | History Quantitative lighting design With the advent of electrical lighting, obtaining illuminance levels similar to those of daylight became a question of how much technical effort one was prepared to invest. At the end of the 19th century, one attempt at provid- ing street lighting was to mount floodlights on lighting towers. However, the glare and harsh shadow produced caused more disadvantages than advantages and so this form of outdoor light- ing was soon abandoned. Whereas inadequate light sources were the main problem initially, a prime concern later on was how to sensibly deal with the overabundance of light. Increas- ing industrialisation gave rise to intensive studies in the field of workplace lighting, investigat- ing the influence of illuminance levels and lighting type on production efficiency. The stud- ies resulted in extensive rules and regulations governing the minimum illuminance levels, the qualities of colour rendition and glare limitation. This catalogue The American Electric Light Tower of standards was to serve as a (San José 1885) guideline for lighting far beyond the area of the workplace; in fact, it still determines the practice of lighting design right up to the present day. However, this approach left the psychology of perception totally unconsidered. The issues of how people perceive structures clearly and how light- ing also conveys an aesthetic effect were beyond the scope of the quantitative lighting rules and regulations. Edition: 20/03/2007 | Updated version at www.erco.com 4 E Guide Basics | History Qualitative lighting design Restricting the view of human perception to a physiologically orientated level led to unsat- isfactory lighting concepts. Approaches at a new lighting philosophy that no longer solely considered quantitative aspects arose in the USA after World War II. Expanding the physiology of the visual apparatus by adding the psychology of perception meant that all factors involved in the interaction between the perceiving observer, the object viewed and the facilitating medium of light now came under consideration. The perception- orientated lighting design no longer primarily thought in the quantitative terms of illuminance levels or luminance distribution, but in terms of the qualitative factors. Edition: 20/03/2007 | Updated version at www.erco.com 5 E Guide Basics | History Perception-orientated lighting design The perception-orientated l ighting design of the 1960s no longer considered man and his needs as a mere recipient of his visual surroundings but as an active factor in the perception process. The designers analysed Richard Kelly William Lam what was the significance of the individual areas and functions. Using the pattern of meaning thus established, it was then possible to plan the lighting as a third factor and to develop an appropriate lighting design. This required qualitative criteria and a corresponding vocabulary, which in turn allowed both the require- ments placed on a lighting system and the functions of the light to be described. Edition: 20/03/2007 | Updated version at www.erco.com 6 E Guide Basics | History | Perception-orientated lighting design Richard Kelly Introduction Richard Kelly (1919-1977) was a pioneer of qualitative lighting design who borrowed existing ideas from perception psychol- ogy and theatrical lighting and combined them into a uniform concept. Kelly broke away from the rigid constraints of using uni- form illuminance as the central criterium of the lighting design. He replaced the question of light- ing quantity with the question of individual qualities of light. These were designed according to a series of lighting functions, which were in turn geared towards the perceiving observer. In the 1950s Kelly made a distinction here between three basic functions: ambient luminescence, focal glow and play of brilliants. Edition: 20/03/2007 | Updated version at www.erco.com 7 E Guide Basics | History | Perception-orientated lighting design Richard Kelly Ambient luminescence produce blanket illumination, or Kelly called the first and foun- ”one size fits all“ lighting at the dational form of light ”ambient supposed optimum illuminance luminescence“. This is the element level, but to have differentiated of light that provides general lighting that builds on the base illumination of the surroundings; layer of the ambient light. it ensures that the surrounding space, its objects and the people there are visible. This form of lighting facilitates general orien- tation and activity. Its universal and uniform orientation means that it largely follows along the same lines as quantitative light- ing design, except that ambient luminescence is not the final objective but just the founda- tion for a more comprehensive lighting design. The aim is not to Focal glow by applying a lower lighting level. To arrive at a differentiation, This facilitates a fast and accurate Kelly came up with a second flow of information, whereby form of light, which he referred the visual environment is easily to as ”focal glow“. This is where recognised in terms of its struc- light is first given the express tures and the significance of the task of actively helping to con- objects it contains. This applies vey information. The fact that just as equally to orientation brightly lit areas automatically within the space (e.g. the ability draw our attention now comes to distinguish quickly between a into consideration. By using a main entrance and a side door) as suitable brightness distribution for emphasising certain objects, it is possible to order the wealth such as when presenting goods of information contained in an for sale or when highlighting the environment. Areas containing most valuable sculpture in a col- essential information can be lection. emphasised by accented lighting, whereas secondary or distracting information can be toned down Play of brilliants The third form of light, ”play of brilliants“, results from the insight that light not only draws our attention to information, but can also represent information in and of itself. This applies above all to the specular effects that point light sources can produce on reflective or refractive materi- als. Furthermore, the light source itself can also be considered to be brilliant. This ”play of brilliants“ can add life and ambiance, espe- cially to prestigious venues. What was traditionally produced by chandeliers and candlelight can now be achieved in a modern lighting design by the targeted use of light sculptures or by cre- ating brilliant effects on illumi- nated materials. Edition: 20/03/2007 | Updated version at www.erco.com 8 E Guide Basics | History | Perception-orientated lighting design Richard Kelly Glass House in the middle ground and the background, thereby making the Architect: Philip Johnson landscape backdrop visible. Location: New Canaan, C onnecticut, 1948-1949 Photos courtesy of the Kelly Collection. It was on this Glass House project that Kelly developed the basic principles of indoor and outdoor lighting which he was to later apply to countless residential and business properties. Kelly avoided the use of blinds for the sunlight because he found they obscured the view and impaired the feel- ing of distant space. Instead, to reduce the harsh daytime bright- ness contrast between inside and outside, Kelly used dimmed lighting on the interior walls. For the night, he designed a concept that works with the reflection of the glass facade and retains the spatial feeling. Kelly recom- mended candles for the interior as this would give sparkle and add an exciting atmosphere. Several lighting components in the out- door area augment the view out of the living area and create spa- tial depth. Projectors on the roof illuminate the front lawn and the trees beside the house. Additional projectors highlight the trees Seagram Building Architects: Ludwig Mies van der Rohe and Philip Johnson Location: New York, New York, 1957 The vision behind the Seagram Building was to have a tower of light that would be recognisable from afar. Working together with Mies van der Rohe and Philip Johnson, Kelly achieved this aim by having the building shine from the inside out. This was done using luminous ceilings in the office levels, whereby a two-stage light switch for the fluorescent lamps enabled energy to be saved at night. The illumined area at the plinth of the building gave the impression that this multi-storey building is floating above the street. An impressive view into the building at night is afforded thanks to uniform vertical illu- mination of the building’s core, produced by recessed ceiling luminaires. A carpet of light starts in the indoor area and continues onto the forecourt. To achieve a uniform pattern of solar protec- tion on the facade during the daytime, the blinds on the win- dows only have three settings: open, closed and half-open. Edition: 20/03/2007 | Updated version at www.erco.com 9 E Guide Basics | History | Perception-orientated lighting design Richard Kelly New York State Theater Lincoln Center for the Performing Arts Architect: Philip Johnson Location: New York, New York, 1965 For the New York State Theater Kelly explored the use of crystal- line structures for the design of the chandelier in the auditorium and the lighting of the balcony balustrades in the foyer. The chandelier in the auditorium had a diameter of about three meters and consisted of a number of smaller ”diamonds of light“. In the foyer, the luminaires on the balustrade were designed to look like jewels in a crown, thereby underlining the grandeur of the room. The light sources were shielded towards the front side of the balustrades, but on the inside their multi-facetted structure produced impressive reflections. This results in brilliance effects comparable with the sparkle of precious stones. In addition, Kelly also conceived the lighting in all the other areas of the Lincoln Center, except the interior of the Metropolitan Opera House. Kimbell Art Museum Architect: Louis I. Kahn Location: Fort Worth, Texas, 1972 The clever use of natural light in the Kimbell Art Museum originates from the teamwork of Louis Kahn and Richard Kelly. Kahn designed a series of North- South orientated galleries whose vaulted ceilings featured a sky- light running along their apexes, while Kelly was responsible for the daylight reflector system made of curved aluminium plate. Perforations allow daylight to penetrate through this plate, thereby reducing the contrast between the underside of this reflector and the daylight-illu- minated concrete vaulting. The central section of this dished aluminium is kept free of per- forations so that direct daylight is shut out. In areas with no UV protection requirements, such as the entrance or the restaurant, a completely perforated reflector is used. Computer programs were used to calculate the reflector contour and the lighting proper- ties that were to be expected. The underside of the daylight reflector system was fitted with tracks and spotlights. Kelly sug- gested putting plants in the inner courtyards in order to tone down the harsh daylight for the indoor areas. Edition: 20/03/2007 | Updated version at www.erco.com 10