LIFE as we know it is based on the electromagnetic interactions between the particles of matter. All the life forms on earth have been evolving and making use of the electromagnetic spectrum in some way or the other to interpret their surroundings and to adapt to their environment.
Visible Light is only a small portion of the Electromagnetic spectrum. It however has a profound effect on the psychological as well as physiological functioning of the animals and humans. The visible light or the absence of it has been deeply tied to the circadian biological clock of the living beings on Earth.
For us humans, however, there is more to it than just the psychological and physiological aspects of the visible light. Our perception of light is deeply rooted in cultural history of humanity. The intrinsic qualities of visible light have shaped every aspect of human life, from Art to Architecture.
Primitive methods of illumination such as candles, gas or oil lamps have been the main sources of artificial light for ages. Several attempts were made to improve the illumination of the conventional candles and flame lamps. A big improvement in lighting power came with the invention of gas lamp mantle during 1885. In the second half of the 19th Century, with the advent of industrialisation, there was an increasing demand for improved illumination, especially in the factories working round the clock to maximise returns. It was however electricity which prompted inventors to develop ways of converting it directly into light. An incandescent light bulb thus came into existence owing to the independent research done by Joseph Swan (Britain) and Thomas Edison (USA).
Since then sources of artificial light have been constantly evolving to produce more and more light per unit of the energy consumed. These highly advanced sources of artificial light have made it easier for us to gain better control over the use of light and minimise wastage of energy. At the same time inventors have been constantly trying to improve these sources to simulate effects of natural light.
Gas Street Lights in Berlin, Germany
There has been a vast amount of research on artificial light and its effects on human health. Many studies suggest that artificial light has adverse effects on human health. The human body is governed by its internal biological clock which regulates its functions, behaviour, sleep etc. This internal biological clock, the Circadian Rhythm, of the human body is programmed to follow the day and night cycle. Natural light is the main factor responsible for regulating this mechanism. But with ever increasing use of artificial light in human life, this natural cycle of the human bodies is being easily affected. Because major portion of the world population lives in and around the cities, most often people are exposed to unwanted artificial light from their surroundings, which plausibly has an effect on their health. It is therefore essential for Architects, Urban Designers and the lighting manufacturers to develop ways to tackle problems associated with artificial light at the same time improving the quality of human life. It is also essential for us to study how artificial light is used in the planning of cities around the world.
Artificial lighting plays a highly visible role in the overall presentation of the emerging city.
It helps increase safety in areas that people use, aids in geographic orientation as people can use well-lit focal points as landmarks to help them find their way. For instance, a well-lit historic place draws attention to the uniqueness of an area as well as highlights the identity of the area, creates a sense of drama.
But creation of such well lit public spaces in a city demands a thorough study and a single strategy; ‘A Lighting Master Plan’ that states the objectives in proper design language and creates a technical framework for planning at local level. It works as a practical guide for the municipal authority in all decisions relating to public lighting.
A lighting master plan is always based on a general concept, which is prepared considering the requirements of the society, the topography, the history, and the rhythm of the town with all its cultural and commercial activities. The concept is then transformed into lighting proposals on a smaller scale for every neighbourhood in the municipality taking into account all key factors: ambience, safety, light pollution and energy consumption. The Lighting Master Plan also contains recommendations for maintaining luminaries and replacing lamps.
Lighting of pedestrian ways and main roads
Such a lighting design guide for a city is drawn from a need to extend the day ambience of the city into the night and thus creating a different set of experience for the visitors.
A Lighting Master Plan helps in expressing the image and character of a city through lighting. It facilitates full enjoyment of outdoor space (which during daytime can be unpleasantly hot) and reduction in energy consumption through careful planning.
One of the important considerations in developing public spaces is the design and placement of exterior lights. Exterior lights, particularly building façade lighting should be architecturally compatible with its surroundings and should not create glare, light overspill or light pollution. Care should be taken in positioning of new lights so that they do not stand out in relationship to the surroundings. Special conditions relating to street character are also important considerations in determining an appropriate light fixture. Qualities such as the architectural or historical character of the building or park edge, the density of a tree canopy, and the degree of ambient light are the factors that strongly impact the effectiveness and appropriateness of various light fixtures and must be included in the analysis of lighting concepts.
All these design considerations form an integral part of a Lighting Master Plan, which gives lighting policy guidelines in order to develop a nightscape that is attractive, environmentally successful and economical.
The design policies may consist of:
- Distinguishing the main roads from the surrounding streets through use of distinct road lighting character. The same concept can be extended to distinguish the market places, squares and residential areas through the use of differing colour values of ‘white’ light.
• Making provision for façade lighting of prominent public buildings and structures as it helps bring out the character of the surroundings.
• Minimising night sky light pollution by adopting good lighting design practice, appropriate equipment specification and proper aiming of installed lighting.
• Establishing maximum limits on the luminance of internally and externally illuminated advertising and signage.
• Defining heights of street light columns in residential areas so that they are in proportion to the scale of adjacent buildings.
• Operational control of lighting throughout the city including lighting for roads, streets, public spaces, structures, landscapes and waterscapes.
Planning At Smaller Scale
Sociability is a difficult quality for a place to achieve, but it can become an unmistakable feature. The sociability depends on the type of activities and the users in a place.
There should also be a good balance between different genders, people of different ages who are using the space.
In many situations, particularly when people are concerned about security, there is a tendency to over-light a park, plaza, street, or other public spaces. But sometimes too much lighting can be just as bad as too little lighting. The key to developing a good plan is to relate lighting to the evening functions of a particular space.
Although its primary purpose is nighttime visibility for security and safety, successful street lighting takes into account the human users of the street. For example, one way to emphasize pedestrian activity over automobile traffic is to replace standard overhead street lights with smaller scale. However, as a luminaire’s height is lowered, the lamp’s brightness must be adjusted so that is does not create excessive glare for pedestrians. At the same time, the lumen output of the fixtures must also be capable of adequately lighting the area.
As mentioned before, a Lighting Master Plan gives inputs for planning on local level. Detailed planning is required at this scale considering the technical aspects such as types of luminaries, lamps, colour temperatures, glare etc.
Apart from these technical aspects, one has to give careful attention to every situation which has different requirements in terms of lighting.
Entrances: Planned evening lighting around building entrances contributes to the safety of an area even more than the use of bright lighting that is not focused on areas of use.
Edges: The edges of a park or plaza, particularly any interesting gateposts, compound walls, and trees visible from the adjacent street should be lit to help define and identify the interior space. Buildings located on the edges of a park can also have provisions for façade lighting bringing attention to the larger area beyond the park.
Architectural details: Lighting entrances, archways, cornices, columns etc. can attract attention to the uniqueness of a building, place, or district and bring a sense of drama to the experience of walking at night.
Focal points: Lit sculptures, fountains, bridges, towers, and other major elements in an area, especially those visible to pedestrians and vehicles, may form landmarks at night.
Landscape: Trees, shrubs can be used to crate dramatic effects like moonlighting. A row of trees lit with ground recessed uplighters defines a pathway or a street and gives substantial reflected light in the space.
Transit stops: People feel more secure when bus or train stations are well-lit. Lighting also draws attention to and encourages use of such amenities.
Signage: Well-lit maps, along with directional and informational signage, are essential to providing orientation at night.
Retail displays: Lighting retail displays, even when stores are closed, not only provides ambient light for the street but can also help to increase the number of people on a street, which is a major contributor to security.
Lighting Master Plan Proposal, Wismar, Germany
Survey of Existing Lighting, Wismar, Germany
Types of lamps & luminaries
Different sources of illumination vary significantly with respect to the quality of light they provide. This, in turn, has a dramatic effect upon the appearance and safety of a place at night. High-pressure sodium, the light source typically used in city street-light fixtures, casts a yellowish-orange glow that results in poor colour rendition; it compromises visual clarity and reduces the overall quality of the nighttime urban environment.
By contrast, metal halide as a light source produces a soft, white glow that renders colour accurately; it offers better visual clarity, improves reaction time for vehicles, and requires less wattage for the same perceived visibility. At the same time, one also has to consider the cultural preferences to the light colour and colour temperatures.
The latest advances in LED technology have made it possible to have better control over the characteristics like beam angles, lumen output, colour rendering etc. Huge reduction in power consumption has been the main advantage LEDs have offered over the conventional light sources.
Glare and light trespass
The obtrusive aspects of lighting, such as glare, trespass, energy waste and sky glow often extend well beyond the boundaries of the area in which the lighting is installed and intended for use. These obtrusive aspects can have serious consequences for the public health, safety and welfare, but they can also be effectively controlled or eliminated with a careful attention to design, installation and use. Glare and excessive contrast caused by poorly shielded luminaries and overlighting affect everyone’s ability to see and as eyes age they become particularly susceptible to these disabling effects.
Though lighting may sometimes be effective in attracting people in a space, overlighting interferes with the visibility on adjacent roads or may disturb the residents of the adjoining area. Therefore balancing of these opposite interests is a crucial aspect, which has to be considered while designing.
Architectural Lighting, after all, is not a magic wand that can transform a place into a successful public space, but it requires planning at all levels and a Part to Whole relationship is of utmost importance.
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