A detail of the Sistine Chapel’s ceiling after the lighting refurbishment and illuminated with the new custom LED lighting system.
Governatorato dello Stato Citta del Vaticano - Direzione dei Musei A detail of the Sistine Chapel’s ceiling after the lighting refurbishment and illuminated with the new custom LED lighting system.

Four hundred and fifty years ago, Michelangelo Buonarroti died at the age of 89, just after putting the finishing touches on two frescoes for the Pauline chapel in the Vatican, only a few doors away from another Vatican chapel where he had triumphed at the beginning of his career. Today, rather than celebrate the anniversary with an exhibition, the Vatican Museums , under director Antonio Paolucci, decided to honor the great artist in a different way: by installing new lighting and air conditioning systems for the Sistine Chapel , ensuring Michelangelo’s masterwork a long and healthy future.

After a massive campaign to clean and restore the Sistine frescoes that lasted from 1981 to 1994, Paolucci is adamant that the chapel should never undergo so drastic a treatment again. The paintings must be protected from future damage as aggressively as possible, which means minimizing exposure both to drastic changes of temperature and to pollutants. To bring about this novel celebration, the museums contacted the firms that had handled lighting and ventilation since the completion of the Sistine Chapel ceiling restoration in 1986: Osram and Carrier, respectively, who worked with the Vatican’s Department of Technical Services, under the guidance of Pier Carlo Cuscianna and Rafael García de la Serrana Villalobos with Roberto Mignucci, and in the Vatican Museums by the Conservator’s Office of Vittoria Cimino and the Diagnostic Library for Conservation and Restoration of Ulderico Santamaria with Fabio Morresi. Given the prestige of this assignment, these renovations have been presented to the Vatican (and to the world) as gifts.

A view of the Sistine Chapel. Pope Julius II commissioned Michelangelo to paint the ceiling, and the work took place from 1508 to 1512.
Governatorato dello Stato Citta del Vaticano - Direzione dei Musei A view of the Sistine Chapel. Pope Julius II commissioned Michelangelo to paint the ceiling, and the work took place from 1508 to 1512.

For hundreds of years, the chapel and its frescoes were lit by the 12 windows high on the walls and by an endless array of candles, whose smoke coated the delicately painted plaster with layer on layer of oily soot mingled with dust and other pollutants from the streets of Rome. After the restoration of the ceiling in 1986, these windows were permanently closed and fitted with special plastic screens to filter out incoming ultraviolet sunlight. Eight 150W high-intensity discharge metal halide lamps with quartz technology (HQI) spotlights and two 1,000W halogen projectors were installed on the outside of each of the windows. The pure primary colors of the 15th-century wall frescoes and the stunning pastels of Michelangelo’s ceiling were spellbinding even with this subdued level of illumination. At the same time, a new system for air filtration and partial air conditioning was installed.

The brilliant new colors of the Sistine Chapel and the continuing development of mass tourism in the years since the restoration began to present the Vatican Museums with a new challenge: what to do with the overwhelming number of visitors, each one a living source of carbon dioxide, moisture, and dust. Annual visitors before the 1980’s numbered about a million; immediately afterwards, that number had tripled. Today, more than six million people troop through the Sistine Chapel in any given year, sometimes at a rate of 20,000 in a single day. In addition, the chapel is where the College of Cardinals sits to elect a new pope, and has ever since the late 15th century. Paolucci does not see a constructive way to limit admission, so he resolved to concentrate his efforts as director on controlling the conditions within the chapel itself.

When it came to the new lighting, Paolucci expressed his hopes for “an illumination that was gentle and at the same time total, non-invasive, respectful of the Sistine’s [complexity]. Not a privileged spotlight on Michelangelo, but the possibility of a quiet, objective, and delicate reading of … ‘the world’s chapel.’ ”

For three years, Osram experts and Vatican personnel studied the chapel’s particular conditions before deploying more than 7,000 carefully calibrated LEDs to create an impressively intense, even light across every surface of the famous chapel. The luminaires are similar to those that the company developed for the reopened Lenbachhaus art museum in Munich with red, green, blue, warm white, and cool white LEDs. The five color channels can be independently controlled to allow fine adjustment of the color temperature between 3000K and 4000K.

As a result, the permanent late-afternoon feeling of the old Sistine Chapel has turned into a uniformly clear light that permits close reading of the paintings in every detail. It is not a natural light as it leaves nothing in shadow, but it is an appropriate light to shed on a monument that has become an object of intense scrutiny by pilgrims, scholars, students, and cardinals, in addition to the hosts of ordinary tourists. Gilt details shine forth from the side walls and glitter from the ceiling; the background landscapes on the side walls snap into a perspective as startling as that of Michelangelo’s fantastic painted architecture on the ceiling. The faces of Hebrew patriarchs, ancient Sibyls, and two future popes can be appreciated with a crisp new precision. Michelangelo’s glorious colors, surely ground and mixed in sunlight, show forth in all their complexity.

The chapel’s architecture provides an excellent platform for the primary luminaires: a projecting ornamental cornice that runs along the two side walls at a height of about 10 meters (33 feet) and is large enough for a person to walk along it. Michelangelo anchored his scaffolding here when he painted the ceiling, and so did the restorers who cleaned his work in the 1980s. Now the luminaires that provide the chapel with its chief source of illumination run along its length, casting their clear, even light on the frescoes above. Forty fixtures, 20 on each side, are mounted in groups of four, each with a total of 140 red, green, blue, and white high-performance LEDs. The fixtures’ reflectors are configured to guarantee homogeneous, glare-free 3500K illumination that reaches precisely up to the upper edge of the painted curtains (originally covered by real tapestries) that adorn the lower third of the chapel interior. Each luminaire is about 80mm (3 inches) wide and with a heat sink of only about 100mm (4 inches) in depth.

The new, custom-configured lighting system is set to operate with three scenes. The first is “Normal,” the primary setting for illuminating the frescoes, ceilings, and walls. The second is “Gala,” which is used for special ceremonies and events such as Conclave when the general light level of the luminaires is increased to a brilliant intensity and 10 LED fixtures are turned on, each with three 50W LEDs spotlights, which are spaced along the length of the cornice, five to a side. Normally these are hidden by the cornice, but when put into use they pivot downward to shed their light on papal ballots and banqueting tables below. Finally, a third preset, which incorporates high CRI luminaires, is used when the fresco of “The Last Judgment,” at the far end of the chapel, requires special lighting.

Even at this level of illumination, power consumption is a fraction of what it was under the old system: 7.5 kilowatts rather than 66, and the significantly cooler temperatures of the LEDs will expose plaster and pigment to much less stress than the hot, intense light produced by the previous fixtures.

In effect, then, the new lighting system is a restoration project in its own right, designed to lengthen the life of these magnificent frescoes and at the same time to reveal them in their full glory. Michelangelo would surely have approved. 

Ingrid D. Rowland teaches at the University of Notre Dame School of Architecture’s Rome program. She writes and lectures on Classical Antiquity, the Renaissance, and the Age of the Baroque for general as well as specialist readers.

Details Project   Relighting of the Sistine Chapel, The Vatican, Vatican City, Rome
Client   The Vatican Museums, The Vatican, Vatican City, Rome
Consultants   Department of Technical Services, the Conservator’s Office, and the Diagnostic Library for Conservation and Restoration of Ulderico Santamaria, all part of the Vatican Museums; Pannonian University, Veszprém, Hungary; the Institut de Recerca en Energia de Catalunya, Barcelona, Spain; Faber Technica, Rome
Project Coordinator and Manufacturer   Osram
Funding   The project, referred to as LED4Art, was supported by the European Funding Program for Information and Communication Technology within the Competitiveness and Innovation Framework Programme
Images, Drawings, and Video   Courtesy Osram

VIDEO:  A behind the scenes look at the new lighting strategy for the Sistine Chapel and the research that went into the development of the new LED lighting system.