February 2001--For more than ten years, the "Luce per l'Arte" (Light for Art) department of ENEL (Italy's national electricity board) has brought back to light over 100 artistic and religious works throughout the country, many of which have been mentioned in LD's pages. For the Jubilee year, La Fabbrica di San Pietro, the organization responsible for St. Peters in the Vatican since its construction in 1506, carried out the restoration of the Vatican Necropolis, which is located under St. Peters and contains the saint's tomb. The organization undertook the restoration with ENEL's financial and technical support.

The project included the installation of a new lighting system to allow visitors to view the various areas of this unique archaeological location.

The program also involved diagnosis and microclimate monitoring to find and stop, or reduce, deterioration before proceeding with the conservative renovation itself: not all damage has been caused by natural phenomena--heavy visitor traffic and previous renovation work with unsuitable materials also contributed considerably to the building's decay.

Pietro Palladino of Milan's Ferrara Palladino & Partners Lighting Engineering and Design (www.ferrara-palladino.it), the firm responsible for designing the system, explains "Problems included a very difficult microclimatic situation. There's a 98% humidity count, and visitors cause a considerable build-up of carbon dioxide, as air changeover is only convective. If there was forced ventilation, the extracted air would draw out all the saltpeter and other salts from the walls, so the restored paintings and mausoleums would become white again. The necropolis is level with the Tiber River, so there's water behind the walls. To reduce the effect of air damage in the mausoleums, automatic glass doors have been fitted in along the route followed by visitors to the necropolis and suitably filtered humidified air has been fed in from the Vatican grottoes. The lighting had to avoid raising the environmental temperature by more than one degree and the temperature had to remain steady--fiber optic illuminators had to be located outside the mausoleums, to keep heat to an absolute minimum."

Apart from problems associated with safeguarding the works of art, such as keeping installed power very low, the minimum threshold had to be found to ensure that the restored works were visible, and in fact levels are between 20 and 40 lux, below normal figures. Approximately 5kW was installed at a cost of almost $295,000, which gives an idea of the care taken with the set-up and with the choice of luminaires. With such a high humidity count, they had to be well protected or watertight--and are in fact all to IP68.

Two different lengthed versions of Agabekov's Louvre LL3 fixtures (5W/12V Xenon lamps with rigid loop base) are used to light the frescoes in Mausoleum R and O, and Medium and Flood versions of Platek Nettuno Full Dry fixtures are in the larger mausoleums.

Says Palladino "The mausoleums containing the tombs and relics are connected by a path, but when the basilica was built, this entire cemetery was buried. What we tried to do was get as close as possible to natural light along the visit route, but since it's only 1.6 meters and anything up to 6 meters high, giving uniform lighting to a such a narrow, high corridor was no easy task. The solution was a combination of fiber optics and recessed wall fixtures: 20 Ilti Luce Light-Box illuminators are used with various types of fiber optics and Martini Mattone brick-shaped wall-mounted fluorescent luminaires are also used. Simes Minieos fixtures are recessed in the flooring in front of Mausoleum F and Philips TMX 36W fluorescent instruments are mounted on the beams supporting the glass paving enabling visitors to walk over the excavations below the Memoria Sud area. Two Fiberstar FIB 405 illuminators and relative fibre optics are used to light the stairs leading down from ground level."

Other instruments used include IGuzzini (Woody and Miniwoody) and Bega (2910 & 2911), all with GE Lighting UV control 20W/12V/GY 6.35 halogen lamps, also used on the Platek units. The Ilti Luce illuminators also have GE halo lamps (Precise MR16 ConstantColor 75W).

Photo: ©Fabbrica di San Pietro/Mallio Falcioni.