"Now you can admire the cathedral down to its last detail"

Pietro, you've been living and working in Milan for many years (perhaps you're even a native of Milan?). Can you firstly tell us something about the cultural importance of the cathedral and the role it plays in the urban fabric of Milan?
I'm not in fact a native of Milan, but you might think so because I've now been living and working here for more than 30 years. The cathedral is not only one of the most majestic and impressive specimens of Italian architecture but also represents the very centre of the city of Milan, both geographically and emotionally. Firstly, the city is characterised by its circular structure that forms a centre in the Piazza, developing outwards towards the outskirts. This purely geographic aspect then develops to become a more personal dimension, acquiring a special sentimental value for the Milanese people who all have a place in their hearts for the cathedral. It's the symbol of their city, with the 'Madonnina' above almost acting as a guiding light, a form of reassurance when they glance up to the sky.

What was your general design approach with the new exterior lighting for the Duomo di Milano?
The intention was to present the cathedral in a way that corresponds to its stature and importance. The nominal brightness of general lighting around the Piazza has continuously increased in past years, and for this reason we also need higher illuminances for the cathedral than were produced by the lighting system installed around twenty years ago.

In 2015 you worked with ERCO to redesign the entire interior lighting of the cathedral using a total of approximately 800 LED luminaires from the Parscan range. Is there a connection between your lighting design concept for the interior of the cathedral and the new outdoor lighting?
This wasn't just about replacements but a completely new project. The obsolete system generated sufficient horizontal illuminance levels but left the columns, capitals and side chapels of the church in twilight. The new project instead aims to prioritise the vertical surfaces in accordance with the Gothic style of the church's architecture. In total we installed 860 luminaires in the interior, and primarily with narrow distribution optics – the high levels of precision of the light distributions enable the capitals and several other details of the church interior to be accented with light. The new external lighting also illuminates the large glass windows, the luminosity of which can be admired from within. This creates real visual connections and references, allowing the architecture to be appreciated in its entirety.

The new indoor lighting of the cathedral with ERCO LED technology proved to be exceedingly energy-efficient. To what extent is the new outdoor lighting an improvement in terms of energy efficiency?
The connected load for the indoor lighting, after we upgraded several luminaires for special purposes, is 26.5 kW. For the exterior lighting we installed 35 kW compared to the previous 58 kW, meaning around 40% less. As part of this though, we need to consider that nominal illuminance levels of the complete building structure have increased by approximately 40% – before they were 50-60 lux and now they're 80-90 lux. Seen in total we can say we've achieved comparable energy savings to the indoor lighting. This result is mainly thanks to the high efficiency and high quality lighting technology of the ERCO projectors with their particularly precise light beams and low levels of spill light.

Milan Cathedral is a landmark in the densely constructed urban space. To what extent is the location a challenge for the lighting concept, taking into account the brightness of the surroundings? How can a building of these dimensions be illuminated without impacting on its immediate surroundings?
In the past 20 years there's been a strong increase in the number of light sources located around the cathedral. This required a slight increase in illuminance on the marble surfaces. I also decided to use LEDs with a colour temperature of 4000K to increase the contrast to the surroundings and improve the perception of details. On the one hand the cathedral can be seen from afar, but on the other it's an integral component of the plaza and must function as such – it does after all tend to dominate the plaza during the daytime.

Italy is a country enriched with historical buildings such as churches. Do you think the Milan Cathedral relighting project will influence the way such monuments are illuminated in the future? In your view, in which direction is the lighting of heritage buildings developing at the present time?
LED technology has changed the discipline of lighting design. Today it's possible to illuminate architectural monuments from much larger distances than previously – we can create higher contrasts and model the forms more efficiently. Our new outdoor lighting of the cathedral confirms our approach of not only illuminating well but definitely better, along with reduced energy consumption. In the past people could look at the cathedral but now they can genuinely observe it, even analyse it. This is, in my opinion, the main difference that will drive the evolution of lighting design in coming years.

Lighting designer: Pietro Palladino

Electrical engineer and lighting designer Pietro Palladino knows Milan Cathedral like the back of his hand: he designed the exterior lighting for the building in the year 2000, which he recently replaced with superior LED technology; in 2015 he completed the current interior lighting, also with ERCO lighting tools. Palladino, born in 1958, is considered an expert in the illumination of architectural monuments which he effectively reinterprets while preserving the historical substance – for example the former customs building "Punta della Dogana" in Venice now converted into a museum. Lighting master plans for Milan and other cities as well as lighting for new buildings such as Venice Airport are also part of the repertoire of the Ferrara Palladino office, run in Milan for the past 25 years by Palladino together with his partner, the architect Cinzia Ferrara. During the course of his career, Palladino has held several positions in professional associations such as APIL (the Italian Association of Lighting Designers). He teaches lighting design at the renowned Politecnico di Milano and has published a number of specialist books and textbooks on lighting design. He became familiar with and learned to appreciate ERCO products early in his career – for example when in the early 1990s he was commissioned by the energy company ENEL to contribute to the lighting of major projects such as the Pinacoteca Vaticana in Rome and the Church of San Lorenzo in Florence.

Veneranda Fabbrica: the Milan Cathedral workshop

So much tradition is unusual: the "venerable workshop", the literal translation from the Italian of the cathedral workshop in Milan has existed for more than six centuries, or more precisely since 1387. At that time, Gian Galeazzo Visconti, the municipal leader of the city, laid the foundation stone of the cathedral and commissioned a committee of noblemen and clergymen to organise the construction work. As with comparable institutions in other European towns and cities such as Strasbourg, Cologne and Vienna, the workshop also took care of maintenance and restoration following completion of the cathedral in 1813. It maintains not only extensive workshops employing stone masons and other craftsmen, but also the quarry in Candoglia, Piedmont where marble has been extracted for the cathedral since construction began. The cathedral museum in the Palazzo Reale on the cathedral plaza belongs to the Fabbrica, as well as a library and the large archive dedicated to the history of the cathedral. First and foremost though the cathedral workshop supervises the continuous construction sites at the cathedral itself – these range from everyday repairs to the replacement of weathered marble elements, fundamental safety measures and technical replacements – for example upgrading the interior and exterior lighting. For this purpose the Fabbrica has an annual budget of around 30 million euros.