As of last month, the Sistine Chapel’s renowned artwork can be seen in its full beauty day and night at no risk to the paintings or the other priceless works, thanks to an extensive LED project.
Photo Credit: ©Governatorato dello Stato della Città del Vaticano
or the first time in several centuries, the annual 4.5 million visitors to the Vatican’s Sistine Chapel in Rome will be viewing these treasures in a completely new color diversity. Until November 2014, the colors of the famous frescoes by Italian master Michelangelo were difficult to recognize in the transition area between daytime and night vision.
Experts from OSRAM (parent company to Osram Sylvania) developed the LED lighting concept as part of a project subsidized by the European Union (EU) and with various project partners, including conservators and experts for color quality and sustainability. The LED lighting concept increases luminous intensity by 5 to 10 times, renders colors more close to reality, and illuminates the fresco areas with a high level of homogeneity that previously were hardly noticed by visitors.
Implementing a new lighting system in the Sistine Chapel was one of the most sophisticated tasks in the world of lighting. The specification for completely glare-free illumination, the strict conservational requirements, the immense historical importance of the Chapel itself, and the globally unique works of art all demand the necessity for a lighting solution characterized by extremely individual and qualitative technology.
Prof. Antonio Paolucci, Director of the Vatican Museums, notes, “The Sistine Chapel contains the most extraordinary works ever conceived by the human mind and is Michelangelo’s masterpiece. We want to honor the 450th anniversary of Michelangelo’s death by providing new lighting for his work.”
The lighting of the Sistine Chapel is a pilot project with the working title of LED4Art, supported by the European Funding Program for Information and Communication Technology within the Framework Program for Competitiveness and Innovation (PSP-CIP). The aim of the subsidy program was to demonstrate new possibilities for LED technology with regard to energy efficiency and improved quality of light, and thus to achieve more rapid market penetration for the new technology. In addition to project coordinator Osram, other partners involved are the Pannonian University in Hungary, the Institut de Recerca en Energia de Catalunya in Spain, and the planning offices of Faber Technica in Italy.
The goal was four-fold: Provide maximum possible conservational protection of all artworks in the Chapel; Offer a significant increase in lighting intensity and uniform illumination without glare for visitors; Create a significant improvement in color rendering of the frescoes; Establish significant energy savings.
How It Was Previously Lit
According to Mourad Boulouednine, Project Manager at OSRAM, the Chapel’s previous lighting system was comprised of eight 150-watt HQI spotlights which, at the time, were installed on the outside of each of the Chapel’s 12 windows. Inside the chapel, there were 34 halogen floods (1,000 watts each) and 30 halogen spots (500 watts each). “However, their high connected load was only sufficient for illuminance values of a few lux on the artworks, because semi-transparent plastic covers had been installed in front of the windows to protect the art from ultraviolet radiation,” Boulouednine explains. “These were intended to block damaging radiation, but they also absorbed plenty of light. This quality of light, termed “mesopic,” resulted in the low-contrast twilight usually found in the Sistine Chapel that impairs color perception and contrast.”
The Solution
Color metric experts initially analyzed the color pigmentation of the frescoes without physical contact at 280 points on the Renaissance paintings to determine the reflected light spectrum. The results served as the standard for the spectral fine adjustment of the LED luminaires to optimally illuminate the famous works of art in their correct color palette. The distinctive technical feature: The custom-produced LED luminaires are capable of controlling the four color channels of red, green, blue, and warm white to enable the frescoes to be presented to visitors just as Michelangelo saw them 500 years ago. Experts from the Vatican and OSRAM specified a color temperature of 3500K in the Sistine Chapel. And, as it turns out, such advanced fine-tuning is currently only possible with LED technology.
The project entailed a complete overhaul of the existing lighting system. There are now approximately 7,000 OSRAM LEDs that evenly illuminate the Sistine Chapel’s world-famous works of art and broken down into three luminaire types. First, there are 40 luminaires indirectly illuminating the ceiling and wall frescoes. Each of these luminaires bear 144 pcs. LED. In addition, there are 30 luminaires for direct illumination of the floor level, plus HiCRI spots for the Last Judgment and the Altar.
[Editor’s Note: Several years ago, there was an erroneous – yet widely circulated – report that LED lighting had degraded the color of Van Gogh’s Sunflowers painting, which created doubt regarding LEDs’ capabilities despite the findings being proved false. We asked Boulouednine if his team was concerned.]
“There was no hesitation in the decision to use LEDs to illuminate the frescoes,” he notes. “Following our work developing a wholly unique lighting solution in the Lenbachhaus Museum in Munich, we determined from the start that the Chapel should receive the same extremely high lighting specifications to ensure that these works of art can be viewed to the greatest effect without causing harm. OSRAM engineers developed an LED luminaire from scratch that is significantly gentler and more caring than all alternative artificial forms of light. Paired with the fine control options inherent in LED technology and a sophisticated lighting algorithm, we have been able to showcase the Sistine Chapel in a way that would not have been possible without LEDs.”
In addition, this specially created luminaire was tested intensively in the Vatican laboratories on pigment samples to simulate hundreds of years of illumination proving that the LED will not do any harm.
Choosing the Right Color
“We chose to use cooler color temperatures in order to simulate the display of the frescoes as Michelangelo would have seen them at their creation,” Boulouednine says. “Thus, the LED luminaire OSRAM developed for the project featured red, green, blue, as well as warm white LED light. Its four color channels are independently controlled to allow for fine adjustment of the color temperature between 3000 and 4000K.”
As previously mentioned, a non-contact analysis of fresco pigmentation at 280 points was performed on the Renaissance paintings by colorimetry experts from the Pannonian University in Hungary. This actual color response (and not the classic color rendering index) served as a benchmark for the fine spectral adjustment of the LEDs. “The Chapel, though, is illuminated with LED light at 3500K, so a sophisticated correction algorithm was developed that integrates the differing color perception of the human eye with various color temperatures into the spectral distribution of the LED light,” Boulouednine remarks.
In addition to using 70 percent less power compared to the previous lighting installation, the difference in illumination and clarity of the viewing experience for new and returning visitors via the new LED lighting is immediately apparent. As a result of the highly precise guiding of light, the art is uniformly illuminated and glare-free. The luminaires are installed away from view but, below the windows to make sure that the light is emitted in the same direction as the natural daylight. Furthermore, the art on the walls is now also properly illuminated and can be appreciated more, whereas before the lighting mostly focused on the ceiling. New and returning visitors will be able to experience the interplay of fresco colors just as Michelangelo intended, and such ambitious fine-tuning is currently only possible with LEDs.
With a color temperature of around 3500K, a lighting level of 50 to 100 lux and a CRI > 95, the paintings of the Sistine Chapel are now illuminated with individually adapted and highly efficient LED light. Plus, the brightness is also completely dimmable. The immense color diversity and 3D effects in the famous art of Michelangelo can now be seen for the first time in all their glory by visitors. Best of all, the historic frescoes are more optimally protected than ever before since LED light causes significantly less damage than all currently known light sources.
Working on the Sistine Chapel project had a profound effect on Boulouednine. “The illumination of such an outstanding location is the best you can do in your life as a light professional. It is an once-in-a-lifetime experience. To be in contact with so many professionals from art historians, material scientists, and colorimetry experts – and also to experience this cultural world heritage – is difficult to describe in words,” he states. “As the project manager, I felt the burden of the responsibility to illuminate the artwork the entire time. When you have the opportunity to come very close (1 foot distance) to many frescoes, you can feel how much of artistry and how much effort of Boticelli, Perugino, Ghirlandaio, and Michelangelo is behind this Renaissance art. Today, the heritage of 500 years of history is looking down to you asking, ‘Is this enough, can you do better? Is this now the best solution you can provide? What else you can do?’ It is really a great honor. And it is a pleasure to see the paintings, the colors and the many details in the frescoes. I learned that art makes you happy. Watching the smile and joy on people’s faces seeing the new lighted Chapel is a remuneration you cannot surpass.” ?
