Light and transparency


"The lighting in smart cities is becoming a topic of conversation when preparing Smart management plans”

“Introducing savings into the systems used to generate light is an imperative priority when planning and implementing cities”


Cities need natural light, obviously, but they also require artificial lighting. Traditionally, in smart cities, this element has been overlooked, even though the current trend is to give it the importance and role it deserves.

Light is invisible, even though this may seem paradoxical. What is visible, however, is the light’s reflection on the elements within its radius of influence. Each element absorbs or reflects certain light frequencies, and it is precisely the reflected light that affects our visual system making up the vision of our environment. Equally important is shadow, which gives objects and spaces attributes such as volume or perspective, and which even affects our cognitive system making us generate important substances for our life cycles and mental processes, such as melatonin.


Light from the engineering point of view

The problem with light at the moment and in the context of urban spaces and personal spaces, is the “engineering” focus it has been given traditionally throughout its history. I say “engineering” focus because the only parameters that have really been considered important when designing lighting systems, have been energy consumption on the one hand, or maximum and minimum light intensities that have to be obtained depending on the usage area being defined. The engineering perspective is necessary and essential, but it does not take into account (generally) other emotional or leisure-related aspects. In order to obtain an intensity and particular energy consumption, it may be indifferent whether the lighting points are arranged in one place or another. However, with respect to other activities, changing the arrangement may mean being able to take a photo with the correct lighting, or being warmer or cooler due to the proximity of the light focus. Not to mention other aspects, like using light as an instrument to communicate states of happiness, or daily circumstances in city life such as a rise or fall in the Stock Market, or when the Spanish national team has won a football match.

Approaching lighting from the engineering perspective is essential, obviously. Not in vain, according to the latest lighting report by the European Commission, “Lightning the Cities” dated June 2013, fifty percent of electricity consumption in cities is due to systems used to light the centre. If we add to this that for the year 2020 the European Union has earmarked a target of increasing energy efficiency by no less than 20%, it is easy to understand that introducing savings to the systems used to generate light is an imperative priority from the point of view of planning and developing smart cities. However, it is not just a question of handling light from an engineering perspective. Rafael Gallego, Lighting Designer since 1998; Associate of PLDA (Professional Lighting Designers Association), CEI (Comité Español de Iluminación – Spanish Lighting Committee) and founding member of APDI (Asociación Española de Profesionales del Diseño de Iluminación – Spanish Association of Lighting Design Professionals) is very clear that “light also has to be planned”. At present, cities are a pot pourri of lighting solutions with predominantly isolated, unconnected ideas which, although they comply with current rulings, clearly reflect a general disorder which is conveyed to the perception of cities by inhabitants and visitors.

It is true that there are significant projects implemented in cities like Santander, Valladolid, Malaga or Badajoz, but they are local initiatives around buildings or specific areas. A management plan that contemplates overall lighting in the context of a Smart City are big words that are only spoken in specific cases such as Albarracín, or on a larger scale in Barcelona, which is defining a management lighting plan based on success stories like Hong Kong. Xavier Trías thinks that lighting must no longer be perceived in Barcelona as a «source of pollution », but as a source of happiness, instead, bridging the distances to Asia and its culture. The city’s management plan, which will favour vertical nocturnal lighting for its emblematic buildings, will have to «highlight their physiognomy» -stated the Mayor of Barcelona during his tour of Asian countries a few months ago.

And it is true, one of the aspects lacking in general city lighting is “vertical” arrangements. Rafael Gallego explains it perfectly, comparing our city streets during the night with tunnels. Rules require that asphalt is illuminated so that cars can travel safely, however consequently light points above the height of four metres are ignored. This leaves pedestrians with a visibility space like tunnel vision, and also leaves buildings in darkness above this height. So therefore, an “engineering” vision” of light leads to a deficient city experience. Or the less, the better. Even from a technical point of view, lighting facilities have questionable features which, without considering other appraisal elements, are omitted from any revisions and checks.

Moving on to lighting on roadways, which directly or indirectly affects the lighting on city streets, and within the framework of the Seminary on Lighting given by Philips on 15 October 2013, Jacobo Díaz Pineda, Director General of the Asociación Española de la Carretera (Spanish Roadway Association), introduced a report on the state of the road network in Spain, where lighting was one of the sections with the greatest failings and weak points. Both due to excess lighting and, by default, due to the lack of solutions for improving energy efficiency or due to errors in developing luminaires, leaving areas of shadow that are ultimately a risk factor for driving.


Light and Transparency


Light from the smart and leisure perspective

Decisions regarding lighting are ultimately taken by experts who, nevertheless, are highly specialised in technical issues. These decisions are made either on the architectural report which is responsible for discussing the remodelling or designing of an urban space, or according to agreements between manufacturers who have been granted the contract to overhaul a specific lighting system. However, these decisions are beginning to lack contributions from experts in designing and planning light from an “experience” point of view.

The model proposed by Abraham Maslow about the “hierarchy of needs” and which illustrates his theory of humanist psychology, can be applied to the world of light. In this model, the base of the pyramid would be the basic needs for light to be able to see what is around us. A bonfire is a solution like any other at this level. Above this, there would be the additional levels, like self-determination, safety or spirituality. And these are the levels that have hardly been discussed from the perspective of light. Initiatives are emerging, but only a few, and they are also rather exotic. However there are studies that directly connect lighting with such critical sectors as health. Research by the Universidad de Haifa revealed a connection between nocturnal light and cancer. According to a new study by the Centro de Investigación Cronobiológica Interdisciplinaria (Interdisciplinary Chronobiological Research Centre) at the Universidad de Haifa, people who live in areas with more electrical lighting during the hours of night, are more susceptible to prostrate cancer in men and breast cancer in women.

The Maslow pyramid, applied to light, would have a significant number of components on the lower levels, where technology and engineering rule when implementing lighting projects. However, in Spain, according to Rafael Gallego, we are still in the Prehistoric period when it comes to lighting. Rarely are professionals consulted who can approach the issue of lighting from the higher levels of the Maslow pyramid, and this is noticeable in daily activities such as taking photographs of monuments at night. Let’s consider the Palacio de Comunicaciones for starters; when trying to take a photograph, the excellent dynamic and smart LED lighting collides with the obstacle by showing the luminaires in Plaza de Cibeles, in the final image, with an intensity and tone that are incompatible with capturing an image of the building in all its splendour. Or with other more daily situations like the green lighting tone that surrounds the luminous Pharmacy signs for several metres.

So, light must be approached from other perspectives. Other initiatives discuss the leisure and tourism aspects of lighting. As in the case of Valladolid and its Ríos de Luz - a project to illuminate a tourist route in a “smart” way in the city of Valladolid, around its most emblematic buildings and areas. The light is considered from the point of view of energy efficiency, and the point of view of information. For example, the museums are illuminated with lights that imitate the city’s coat of arms, or the churches show the liturgy with a particular colour coding.

In Badajoz, during the Noche Blanca, a space is prepared for a multimedia show based on light and flamenco; and we must not forget long-standing initiatives like the Montjuic fountain in Barcelona, which has a show based on light, water and music. Córdoba is another city interested in improving lighting for the purpose of tourism, and also Toledo, which has been working for years on lighting its buildings to try and increase the number of night visits to the city.

In the Lighting Plan for the city of Barcelona, one of the areas that they are going to improve first will be Paralelo, using light as a safety and lighting element, but also to help support the identity of this very characteristic urban area.

At any event, to consider “experience” or “emotional” lighting, and even to consider the section on efficiency from the engineering perspective, sophisticated technology is needed. In this section, there is one technology that deserves special attention: LED technology. Light Emitting Diodes are light sources based on solid state components as opposed to the technologies using incandescent filament, steam or conventional fluorescence. These solid state components, when formulated appropriately, allow very intense light to be generated with a useful life of tens of thousands of hours. LEDs have evolved quickly, even more so than expected at the beginning, and today it is a viable alternative for conventional systems using fluorescence or incandescence, with very reduced consumption levels and much more satisfactory maintenance than traditional systems.

Nevertheless, Rafael Gallego also comments on this, warning that although LED has optimum maintenance, the components around the LED do not. For example, the durability of power sources is similar to that of other systems, and so in the end, repair policies would have to be planned according to these components. On the other hand, LEDs are very sensitive to high temperatures. In traffic lights or pedestrian crossings we often see dead LEDs due to excessive heat, and this overrides all their virtues. As an example of these circumstances, we have the decision taken by the city of Goteborg in Sweden, where in a lighting conference in 2011, they decided to replace the mercury vapour lamps activated by compact fluorescence, with LED technologies after weighing up the pros and cons of both solutions.

In the near future we are looking at OLED technology, which is similar to LEDs in that it is an emissive technology albeit with peculiar features which make it unique. So, for example, whole OLED panels can be built that are able to illuminate uniformly, instead of in bits as happens with LEDs. It works with flat light sources for walls, for example, opening the gateway to new ways of decorating and illuminating areas.

Santiago Erice, Technical Director at Philips Lightning, provided much data on these technologies in the Lighting Seminar given by Philips on 15 October 2013. As well as the actual technology itself, we also have to consider bureaucracy. Not in vain the new European ruling, EcoDesign DIM2 which came into force this September, very accurately defines the requirements that must be present in the elements making up lighting systems, so as to help improve the final quality of the solutions implemented using LED technology.

There are numerous success stories from Philips where a significant improvement in energy savings and efficiency combines with quality lighting. Torre Realia in Madrid has managed an 86% saving on its energy expenses, and also to reduce the temperature by 2 degrees after installing LED systems. Avenida Josep Tarradellas in Barcelona has saved more than 70 % after installing LED luminaires. And in Torrejón de Ardoz more than 60 percent, with a significant improvement in the quality of street lighting.


There is still a long way to go

At the moment, the lighting in smart cities is becoming a topic of conversation when preparing “Smart” management plans. However, there is still a long way to go until lighting is integrated and centralised together with the other elements in Smart City systems. For the moment, there are approaches to a “Smart” philosophy, but only partially. For example, it is possible to light buildings using an App in some Spanish cities with tourist routes, whereby by paying a certain amount of money it is possible to activate the lighting on the building or monument in question. There are studies looking into the possibility of using lighting on roadways to indicate alert situations, such as an accident, changing the luminaires around the collision point to red. In some cities lighting is used to indicate the geographical orientation of streets, as in Lyon, where the streets parallel to the river have a particular lighting, and the streets perpendicular to it have a different kind of lighting.

In cities like Valladolid or Santander they are studying applications which allow citizens to monitor or even control lighting, to a certain point, without omitting automatisms like presence detectors which activate and deactivate street or road lighting depending on whether there are pedestrians or vehicles.

Studies are also in progress regarding technologies such as laser lighting to create limited spaces for dynamically created light beams. Nike has used it to “draw” game tracks in urban events, and there are accessories for bicycles like Xfire Bike Lane, which dynamically creates a mini bike lane around the cyclist as he/she pedals (

For the moment, light is still largely handled from a traditional optical point of view, albeit, thankfully, with some technological details that show the way ahead. At least with a view to cities. With a view to citizens there are already “Smart” solutions that allow people to control lighting smartly from an emotional perspective. Philips Hue is one of these products that are helping to introduce this aspect of light in terms of leisure and communication.

Philips Hue is a home lighting system where a centralised control system manages up to 50 LED light points, and with the capacity to change the tone and intensity of the lighting, either together or independently, and which can also be controlled from a mobile app or from an Internet website. Recently the development API was opened, and so, for several months, programmers have been able to integrate integrate Hue technology into their apps.

Light is an essential element for life, and the Smart City is the setting where most of the population will live within two decades. It is important to start lighting our cities not just so that we can see, but also so that we can live. A life seen through rose-coloured spectacles, and spectacles in all colours.

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