View the Sistine Chapel in a Whole New Light
The Sistine Chapel in Rome is recognized as the most important chapel in the world and accommodates perhaps the most extraordinary frescoes ever created by human hands. Five and a half million visitors crowd into the chapel each year to see Michelangelo's works, but they witness only a few in full glory because of the poor lighting. A new type of lighting from Osram will change this - luminance levels will increase, energy consumption will be cut and the art will be carefully conserved.
Now coinciding with the 450th anniversary of the death of Michelangelo this year, LED light will illuminate the artist's masterpiece "The Creation of Adam" as well as other works accommodated by the chapel. Art lovers visiting the interior of the Sistine Chapel will be able to experience the art in a completely new diversity of color.
Lighting experts from the company Osram developed a sophisticated LED lighting concept that increases luminance by five to ten times, elevating the colors from the semi-darkness of twilight and illuminating the complete color spectrum of the frescoes in highly homogeneous and optimally controlled light. The development was implemented within the framework of a project subsidized by the European Union with a consortium of various development partners including lighting planners, conservationists and energy and light measurement technicians.
Experts use the term “mesopic” for the low-contrast twilight usually found in the chapel that impairs color perception and contrast. This quality of light is due to former technical limitations, the currently installed lighting technology originating in the 1980s. Eight 150 watt HQI spotlights and two 1,000 watt halogen projectors are currently installed on the outside of each of the 12 chapel windows. Their high connected load is only sufficient for low luminance values on the artworks, because semi-transparent plastic covers have been installed in front of the windows to protect the art from ultraviolet radiation. These are intended to block damaging radiation, but also absorb plenty of light.
For this new project the options inherent with LED technology are exploited to the full and the aim is to achieve an impression of color that more closely justifies the high component of saturated colors in the frescoes.
The first stage in the project was the analysis of fresco pigmentation at 280 points on the Renaissance paintings by colorimetry experts. The analysis points were illuminated with a calibrated light source and the reflected spectrum measured. This actual color response serves as a benchmark for the fine spectral adjustment of the LED luminaires.
Today, experts assume that Michelangelo did not mix his colors under candlelight or the light of torches but with daylight and thus with a cooler color temperature. Therefore, 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. It is highly probable that visitors will be able to experience the interplay of fresco colors just as Michelangelo once intended, and such ambitious fine-tuning is currently only possible with light emitting diodes.
Because ultraviolet and infrared radiation components are almost completely absent from the LED spectrum, the lights can be installed on a narrow ledge in the interior of the chapel and no longer have to be banished to the outside. 40 luminaires, 20 on each side, will be mounted in groups of four, and the lights accommodate a total of 140 red, green, blue and white high-performance light emitting diodes. A sophisticated configuration of the reflectors guarantees homogeneous and glare-free illumination that reaches precisely up to the upper edge of the artificial curtains that adorn the lower third of the chapel interior.
Despite significantly higher luminance values and maximum light quality, the LED installation achieves top values in terms of electricity overheads, electrical power consumption of the chapel including gala and visitor lighting being reduced from over 66 kilowatts down to 7.5 kilowatts.
The lighting of the Sistine Chapel is a pilot project with the working title of LED4Art, the aim of which is to demonstrate new possibilities for LED technology with regard to energy efficiency and improved quality of light. If the project is successful, LED lights could be installed in museums and cultural sites throughout Italy.