The uppermost portion of the monumental Belvedere Courtyard designed by Bramante in the 16th century, commonly known as the “Cortile della Pigna” (Pinecone Courtyard) on account of the statue of Roman origin that adorns it, is currently undergoing a major restoration effort carried out by the Violi company on commission from the Vatican Museums.
Part of the Vatican Museums complex, the “Cortile della Pigna” is bound by a two-flight stairway that surrounds the exedra in which the famous Roman monument is found. The priceless setting suffers from extensive problems traceable to centuries-old build-up of dirt and smog. The restoration experts of the Violi company have decided to resolve these problems using the IBIX Media Cleaning System.
This innovative method uses micro-air-abrasion systems that projects inert material at low pressures. The IBIX models employed, TRILOGY 28 and TRILOGY 40, are equipped with HELIX helicoidal vortex guns with conical nozzles. TRILOGY brings together the very best in IBIX technology for the cleaning of historically valuable surfaces, combining in a single system the three main operating modes of the IBIX method: dry, steam, and with the HELIX helicoidal vortex gun. Inside the HELIX gun there is a vortex generator made of tungsten carbide, a highly abrasion-resistant material that causes the inert material to rotate as it leaves the gun, this means that the air flow and the inert material reach the surface treated tangentially rather than perpendicularly. This ensures a more delicate approach to restoration projects without diminishing the machine’s performance since rotating motion favours the detachment of alien matter.
The method used to clean the “Cortile della Pigna” involves low-pressure (3 bar) projection of IBIXART Extrafine natural inert, an almandine mineral that neither crumbles nor flakes, thanks to an elevated hardness of 8 on the Mohs scale (diamonds are rated 10). These features make for an extremely effective treatment with reduced quantities of material and at extremely low operating pressures, guaranteeing the delicacy of the operation. And the weight of the material ensures that the granules fall within a limited area around the work zone, drastically reducing the amount of dust.
The travertine marble found in the “Cortile della Pigna” will be cleaned with the microair-abrasion method, effectively removing the harmful layers of soot while preserving the authentic historic layers and the underlying material. Another application of the method is selective removal of paint layers along with the cleaning of plaster. It is expected to treat the wall removing the existing painted layer so it is prepared to receive a new painted layer without the risk of stripping off any layers of plaster and avoiding any aggressive method. The plaster will be restored only in those spots where it is deteriorated. Thanks to the low invasiveness of the method and the limited amount of dust produced in the working area, still protecting correctly the working site, the cleaning procedure can go on throughout the day without interfering with activities underway in adjoining spaces or with the flow of tourists and visitors, even during peak visiting hours in the Vatican Museums.
The use of IBIX technology guarantees maximum respect of the historic materials and full cleaning of the architecture surfaces. The method is based on a scientific approach that combines the diagnostic and planning phases with the treatment itself. There is no room for second thoughts in cleaning operations, given that the process of removal cannot be reversed, which makes it of fundamental importance that the operation be carried out as gradually as possible, with the action of the machine under the full control of restoration professionals. Meeting all the important conditions of the technique it is aimed to free from pollutant deposits and stains the plaster and the travertine marble of Bramante’s courtyard, the magnificent jewel of the monumental complex of the Vatican Museums.
[by Caterina Giovannini, text Raùl Musiate Arellano]