Recreating the Ancient Spirit of Pompeii with Light

According to the poet Horace, the streets of ancient Rome were unlit and populated by undesirable characters at night. We must therefore assume that the empire's smaller towns, such as Pompeii, weren't even lit by torches after dusk. Therefore, the new system for illuminating the ancient town had no historical documentation to enable new instruments to be based on the position, shape, or other features of the original light sources. The criteria behind this project was to avoid turning the town into a spectacular place with a light “show,” but rather to use lighting to indicate the original characteristics of Pompeian life up until the final catastrophic eruption of Mount Vesuvius in 79AD submerged the town under about 10' (3m) of ash, burying everything except the roofs of some buildings.

To draw up the design for such a complicated, delicate project dedicated to this fascinating tourist attraction, Pompeii's Archaeological Service contacted the Luce per l'Arte division of Italy's ENEL national electricity board, an organization with lengthy experience in illuminating locations of significant archaeological and artistic value. The Roman architect/LD who received ENEL's brief for designing the lighting for the first lot of the 136 areas within the Pompeii site to eventually be illuminated was Alessandro Grassia, who has already worked on key designs for ENEL in the past, including Lumina, an ambitious project that illuminated 15 historical Tuscan basilicas (see LD March 2000).

Grassia explains, “The planning stage started in 1998, with preliminary analyses by professor Corrado Terzi and his team, in collaboration with the government Monument and Fine Arts Service, based on a critical historical study of the area and the town's layout.

“With the valuable assistance of Giancarlo Arrigoni,” he continues, “I worked in-depth on designing a series of lighting systems dedicated to the individual archaeological features, bearing in mind the historical and civic connotations of the actual monuments as well as their use in the past. The idea was to enable evening visitors to Pompeii to see the excavations from a completely new point of view, in which the fixtures favor the understanding of the monuments and recreate their ancient spirit.”

The system allows the excavations to be lit in two distinct stages: The first illuminates the perimeter walls, entrance gates, and streets, and remains on for the duration of visiting hours, emphasizing the area occupied by the excavations and the axis on which the town was built. In this first lot, this circuit involves the Stabian Gate, Via Stabiana, and the walkways used by the visitors. The permanent lighting also addresses the need of safety and legibility on the routes followed by visitors. The roadway is lit by a series of iGuzzini Radius floodlights with Philips CDM-TD 70W lamps.

The idea of this particular configuration arose from the possibility of viewing the archaeological area from certain vantage points, such as the Tower of Mercury, la Casina dell'Aquila, from where visitors can see the characteristics of the formation of the town and at the same time have an overview animated by switching the monuments' illumination on and off, like a town which is still alive.

This concept is followed not just on the streets and the facades of the overlooking buildings, but also the old stores and workshops whose doors were on the main road. Here the illumination is mainly horizontal, achieved using “light blade” optics groups, which defined the public area of the locations. Vertical illumination is used for the interiors of the stores and the areas visible from the street, which further illustrates elements of their original character.

The second stage is subdivided into separate circuits, involving the architectural, archaeological, and artistic features, which are switched on by the guide, via an infrared remote control when he or she enters the site with a group of visitors.

The locations chosen were all studied in detail in order to tell their stories with light. Once inside with the group, the guide switches on one or more groups of fixtures and describes the area. In some cases, it was also necessary to use museum-type lighting to enable viewing from a very short distance to appreciate the detail.

Grassia continues, “We decided to keep luminance values very low, so that the visual perception of illuminated objects depends mainly on the contrast between them and the surroundings. We also had to take particular care to avoid damaging frescoes and paintings (never exceeding 150 lux and using anti-UV lamps), and these were the criteria used when deciding the size and quantity of fixtures. To set a numerical value for the luminance levels used, we classified the various materials found most frequently in Pompeii's architecture and analysed their chromatic and reflecting characteristics, eventually reducing the field to the five most commonly found: walls with a reticulate structure, those with stripped work, brickwork, walls built using material of uncertain nature, and the cobblestones of the roads.”

The chromatic components of the different materials involved (mortar, stone, bricks) were then broken up and Gauss' formula used to obtain measurable average values on the RGB scale, which enabled Grassia to assign various reflection coefficients and establish luminance levels as follows: high luminance to accentuate crossroads, fountains, and particularly important features; medium luminance to emphasize monuments and areas of particular interest; low luminance for basic roads and paths.

Continues Grassia, “The fixtures used along streets and inside buildings open to visitors have lamps with natural white light (3000K, 90CRI), whereas features to be highlighted or those built from suitable material are lit by lamps with cool white light (4200K, 93CRI). Inside the houses, we used warm light (2550K, 85CRI) to accentuate the environment's domestic nature. Frescoes and mosaics have filament halogen lamps, which give the best color rendering when using artificial light.”

There were considerable problems involved in installing the system, which had to be as compact as possible: eliminating almost all external splitter systems, and fitting all fixtures which didn't have it as a standard feature with an internal five-conductor splitter system and twin cable glands; using an armored multi-pole mains cable, with steel braid sheath, which enabled conduit to be eliminated, and connecting the sheathing with special ground plates, forming a valid system for protection against lightning risks.

“We weren't able to plan in advance the precise routes to be followed by buried cable runs,” explains Grassia. “In spite of the extreme care taken at the design stage to avoid going any deeper than 20 or 25cm [8-10"], it was often necessary to change the foreseen route and install longer runs than planned because of the discovery of archaeological remains, layers, or ancient paving or flooring. In this sort of situation, excavations, even if not particularly deep, are carried out by taking a sample at the beginning, one in the middle, and one at the end, under the constant supervision of the site manager and the government-appointed archaeologist. If nothing was found in any of the three, work went ahead cautiously by hand, using a small trowel and stiff brush. If, on the other hand, something was found, it was photographed, the position indicated with a sign, a suitable new run chosen, and the same procedure repeated.”

For positioning of instruments, Grassia says, “Wherever possible, fixtures were positioned on the protective roofing over some areas or other modern structures. If this wasn't feasible, we tried to find positions which weren't visible from the route followed by visitors, such as behind the columns indicating the entrance to the stores and workshops. Where the make-up of the ground allowed it, we used buried uplights.”

The area involved in this first stage is the so-called “theatre zone” located to the south of the town near the Stabian gate. The buildings involved on this first lot include the Gladiator's quadriporticus, where a Philips fiber-optic system has been installed, and the Sculptor's house/workshop, visible from the Stabian Way, as is the Temple of Jupiter. The largest systems are installed at the small Odeon theatre and the Temple of Isis. At the former, “stage” lighting to accentuate the proscenium and orchestra area, just like during a show, consists of iGuzzini Platea asymmetric floods with Philips CDM-T 150W lamps. The fixtures illuminating the tiered seating and the perimeter walls are normal versions of the same instrument, used to highlight the unusual geometric relationship between the interior and the exterior of the theatre.

In the Temple of Isis, the colonnade is illuminated by blades of light projected by a series of eight Platea floods with CDM-TD 70W lamps installed on the top of the perimeter walls. The area between the colonnade and the temple is left in shadow, with only reflected light. A dozen iGuzzini Garden buried uplights with adjustable optics and CDM-T 70W lamps are installed along the edge of the building. Another 16 Platea instruments with warmer-toned Philips SDW-T 100W lamps are installed inside the temple.

Grassia concludes, “After seeing the results of this first phase, we're awaiting the go-ahead for the next step in this truly unique project.”

Mike Clark is an Italy-based UK writer specializing in lighting and audio. He can be contacted at mclark@rimini.com.