Week 6: Restorers at work, first phase of cleaning underway

The restorers are proceeding on the eastern side with the first phase of cleaning the frieze, with the application of essential oils and a carrier, an agar agar gel or funori seaweed. The solution of thyme and rosemary oil is diluted in water, and a carrier is used to hold it in suspension on the stone surface. Lichens, now necrotized, were then mechanically removed and dark deposits of cyanobacteria, microorganisms that form a clearly visible black patina, were brushed off the surface.

During the removal of some of the grout, the presence of red biodeteriogens (algae, lichens and mosses) was revealed, which will be analyzed to discover their nature.