Highly modern LED light are illuminating the world famous Sistine Chapel in Rome since November 2014. The Chapel is already presenting its treasures to 4.5 million visitors yearly in a completely new color diversity, because until now the colors of the famous frescoes by the Italian artist Michelangelo were difficult to recognize in the transition area between daytime and night vision.
OSRAM experts developed the LED lighting concept as part of the project LED4art. Such project, finished the last 31st December 2014, was subsidized by the European Union and accounted with the participation of various European partners, including conservators and experts for color quality and sustainability: IREC (Catalonia Institute for Energy Research), FABERtechnica (Italy) and the University of Pannonia (Hungary). The LED lighting concept increases luminous intensity by five to ten times, renders colors more close to reality and illuminates fresco areas with a high level of homogeneity that previously were hardly noticed by visitors.
Figure 1: New LED lighting in the Sistine Chapel.
The new LED light system consists of three separate installations:
1. Gallery lighting illuminating the frescoes on the walls and ceiling.
2. Gala lighting used as supplementary lighting with conclaves and events.
3. Lighting on "The Last Judgment" fresco.
Implementing a new light 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.
1. Maximum possible conservational protection of all artworks in the Chapel
2. A significant increase in lighting intensity and uniform illumination without glare for visitors
3. A significant improvement in color rendering of the frescoes
4. Significant energy savings
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 3,500 Kelvin in the Sistine Chapel. Such advanced fine-tuning is currently only possible with LED technology.
The special LED luminaires were installed at a height of around ten meters on a narrow ledge in the interior of the Chapel, and are concealed from view for visitors while giving the impression that their light comes in the form of daylight via the windows. The project team was also able to avoid all forms of glare to 100% with the new installation.
Figure 2: The specifically constructed LED luminaire can be individually calibrated according to the color spectrum to be illuminated via four separately controllable color channels.
New LED special luminaire
20 LED luminaires on each longitudinal side of the Chapel were installed for visitor lighting purposes in "groups of four" on the ledge. The luminaires contain a total of 140 red, green, blue and white high-performance light emitting diodes. The intelligent configuration of reflectors ensures highly uniform and glare-free illumination. The original design of the luminaires was made more slender, enabling them to fit on the narrow ledge. Each of the luminaires has an approximate width of 80 centimeters, and with the heat sink a depth of around 100 millimeters.
LED spots were also installed. These replaced the obsolete gala lighting used with fairs, concerts and of course for the conclave. 30 LED spotlights with 50 watts each were mounted in groups of three between the windows. When required these are motor-driven onto the ledge from their concealment.
Detailed product images
With a color temperature of 3,500 Kelvin, a lighting level of 50 to 100 lux and a CRI > 95 color rendering index, the paintings of the Sistine Chapel are now illuminated with individually adapted and highly efficient LED light. 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. The historic frescoes are more optimally protected than ever before, because LED light causes significantly less damage than all currently known light sources.
Despite significantly higher lighting intensities and best possible quality of light, energy audit developed during the project reveals that energy consumption has been reduced by a 79 % which represents a CO2 annual average saving of around 25 ton CO2 eq.