Is there a designer who does not dream of the perfect lighting concept, which conveys a feeling of well-being and shows the architecture at its best? Unfortunately, however, it is often the case that the brief received from the client causes difficulties. All too often discussions are peppered with such terms as LEDs and lux levels,causing an unconscious shift in thinking in the direction of norms and technology instead of placing questions about requirements and lighting quality at the centre of discussion. But what exactly is quality lighting design?

Voilà: Lighting design with LEDs!

Looking at their latest holiday photos taken in the Mediterranean the young client is enraptured. The glistening play of light of the sun on the water pushes aside all thoughts of everyday stress. On arriving home and checking his calendar he sees that he has the initial meeting with the lighting designer to discuss the new office building. Inspired by numerous LED luminaires in office and lighting journals the client has formed a clear picture for himself of what good lighting is: lighting design with LEDs, because these are modern and save energy. Yet, precisely because he still has very clear impressions of his holiday, the client ought to ask himself what the exact qualities of daylight were which left such an impression on him in the Mediterranean and how these can be integrated into artificial lighting.

In an age of high-performance light-emitting diodes designers often come across clients who quite determinedly combine all their ideas of good light in one term: LED. In the same way that the feeling of a good holiday cannot be communicated by referring to the mode of transport, be it car or plane, the word LED cannot help us in our search for a suitable/appropriate lighting concept. Of course, certain technical attributes such as a long life cycle or high luminous efficacy contribute to an economical lighting solution. But the designer does not acquire a clear profile of the desired ambience and the individual lighting effects required.

The freedom which we grant the client to think primarily in terms of LEDs provides no guarantee for successful lighting design. The first draft for successful lighting design should result from an exchange of ideas about lighting quality, based upon which a decision can be made as to the tools for achieving a particular lighting strategy, and after which the appropriate light sources can be selected. With the introduction of new technologies for creating light - once upon a time it was the fluorescent lamp, today it is the LED - the processes of quality lighting design have not changed. The lighting concept has priority, and the lamp is merely a tool for implementing this concept.

Perfect planning with numbers?

Just as there is the technophile client who focuses all his ideas about lighting on the word LED, there is also a second type of client who defines perfect lighting on the basis of key figures such as illuminance and uniformity. Wanting to take no risks, he relies on norms such as the current EN 12464-1 which summarizes, for example, the most suitable lighting for a place of work via these 4 values: illuminance ≥ 500 lx, glare rating ≤ 19, uniformity ≥ 0.6 and colour rendering ≥ 80. In this way the designer has a few technical indicators, but here a quantitative understanding of light dominates and the aspects of design are ignored. No one choosing a holiday destination or buying property would take a decision entirely on the basis of four figures such as the square metres, the number of rooms, the ceiling height and the energy consumption.

Thinking in norms focuses first and foremost on safety at work and legibility, and the design aspect is not taken into consideration. In the course of a project, such a client will keep a close eye on adherence to figures – even though visually he is not able to notice whether values are adhered to and is hardly able to register if there are deviations. The search for a qualitatively good lighting solution continues to be vague.

Developing attractive lighting concepts without LEDs and figures?

Pioneers in lighting design such as Stanley McCandless, Howard Brandston or Richard Kelly were very aware that the criteria of illuminance and uniformity are not really able to lead us towards an appropriate lighting solution which creates a feeling of well-being and does justice to the architecture, so they adopted a change in perspective. When developing a lighting concept, they did not ask about quantity but quality and thus the efficacy of lighting. Their aims in lighting design went far beyond efficiency, legibility and safety. Questions about the emotional effect, the ambience required in different situations during the course of the day or the highlighting of materials and architecture have since become an integral part of quality lighting design. Moreover, nature, with its numerous and permanently changing characteristics, shows us the importance of brightness, color temperature, direct or diffuse light, brilliance and the incidence of light for attractive lighting. Quality lighting design starts with people and inquires, during the project analysis, about needs and requirements, such as whether the project is private or public sphere, or whether it has a calm or lively atmosphere. Simply by changing from wide light distribution to narrow light beams a restaurant can be converted from a disagreeable open space into islands of private communication by illuminating the individual tables. When it comes to the architecture, quality lighting design examines how a user's orientation in a building can be improved by light and how materials can be highlighted to their best advantage.

Good lighting concepts must focus holistically on function, psychology, architecture, economic efficiency and ecology. Otherwise we can call them neither attractive nor sustainable.

What is lost if our feeling of well-being and our ability to see is improved?

If when developing a lighting concept we focus on the effect of light as the aim of good lighting, then the relevance of the efficacy of the lamp and the luminaire loses significance to the benefit of human perception and well-being. Even the criterion of illuminance fades in importance, since by measuring this value we learn only how much light hits a surface and not how important the surfaces are for the perception of brightness, or how these surfaces reflect light into the eye. Walls have a great impact but are given little consideration in lighting solutions, even though they fill a large area of our field of vision. By deciding on quality lighting design we free ourselves from a simple or naive understanding of light which is made up of a combination of a few individual parameters and is driven by the search for quick results. It should go without saying that sustainable lighting design will, in the final instance, ignore neither energy-efficient lamps and luminaires nor technical and economic aspects.

This article originally appeared on the DIAL Blog.

Light matters, a monthly column on light and space, is written by Thomas Schielke. Based in Germany, he is fascinated by architectural lighting and works for the lighting company and academy DIAL. He has published numerous articles and co-authored the book “Light Perspectives”. For more information check www.arclighting.de or follow him @arcspaces.

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