How to cure a 1500s canvas with bitter orange hydrosol and cinnamon bark essential oil. The technique green used for this special patient, attacked by fungal biodeteriogens, was developed by the microbiologists of the Catholic University – Fondazione Policlinico Agostino Gemelli IRCCS in collaboration with the Opificio delle Pietre Dure in Florence.
“Il Silenzio”, a work by Jacopo Zucchi, painted in 1572, arrived in Florence from Rome at the behest of Ferdinando I in 1588, to adorn the wooden ceiling of the Terrace of the Geographical Maps of the Uffizi Gallery. The hall, which represents the glory of the Medici family with a map of all the domains of the Grand Duchy of Tuscany, has been reopened to the public after two years of restoration.
In order to still enjoy these ancient masterpieces, it is necessary to protect them from biodeterioration, that is from microbial attacks and, to do so, chemicals that are dangerous for the works and for man are often used. We speak of biodeterioration when a growth of organisms is identified which, with a process of a physical or chemical nature, can produce alterations on the material of which the object is composed.
Essential oils also for Vatican marbles
“All works of art are subject to deterioration – explains the doctor Maura Di Vitoresearcher in Microbiology and Clinical Microbiology at the Catholic University, Rome campus – biodeteriogens are everywhere and humans must intervene to slow down the process “.” For years I have been studying the history of essential oils and hydrolates, then I approached Cultural Heritage and I thought about the possible new use of these substances, they called me from the Vatican Museums for advice on marble and from there I began to use essential oils first on marble, then on paper and finally on paintings “.
Natural antimicrobials
The work on Zucchi’s canvas was carried out in collaboration with the doctor Debora Minottirestorer, the doctor Daphne De Lucarestorer and contract lecturer at the University of Urbino and the professor Francesca Bugli, colleague of Di Vito. The team has been carrying out studies for some time on the use, in restorations, of essential oils and hydrolates, a co-product of distillation, from which essential oil, in fact, and aromatic water, i.e. hydrolat, are extracted., used for its antimicrobial action.
The cure
The painting was attacked by fungal biodeteriogens, more than one stump, on the back of the canvas. The first step was to type the pathogens, that is to identify the strains responsible for the deterioration of Silence. The technical direction of the restoration, entrusted to the Opificio delle Pietre dura, was asked to take samples from the canvas, passing swabs and using a special scotch tape created to collect the microorganisms. The work was completed by doctor Minotti, restorer, and the material sent to the Microbiology laboratory of the Agostino Gemelli IRCCS University Polyclinic Foundation. Once isolated, the two fungal strains were tested with a formulation based on bitter orange hydrosol (Citrus was. amara) and a small amount of cinnamon bark essential oil (Cinnamomun zeylanicum). “The hydrolat was developed for the paper environment, by doing tests on the canvas we had to modify the application and add a small amount of cinnamon from the bark, creating an instant emulsion to be applied under spray on the back of the canvas”.
The treatment
The mix created was sprayed on the back of the canvas on which a sheet of absorbent paper containing the same substance was also placed. Everything was then closed in a melinex bag, a polyester film, and placed for the first hours on a heating and suction table. This was a fundamental step for the fungi to enter the replication phase and open the spores, allowing the mix to better penetrate and neutralize the biodeteriogens.
Human Brains, an exhibition tells about the studies on the brain between art, science and philosophy
by Elena de Stabile
April 29, 2022
The next day the canvas was dried. Subsequent swabs, sent back to Rome, showed no fungal growth. “In this way, Dr. Minotti was able to begin the restoration of the work. The mix used is important because many times the restorers find themselves having to use chemicals that are harmful to health. There are various studies on the subject, somewhere in the world they are already essential oils were used for works of art but no one had ever introduced a hydrolat in combination. Essential oils can be a pharmacological resource and should be used carefully, while the mixture used for Silence it is 99% hydrolate, therefore a versatile and not harmful solution to use. “We were thinking with Daphne De Luca to now tackle new types of restoration, such as murals, subject to all types of atmospheric agents, and where the water arrives, you know, it comes in mushrooms and everything else”, concludes the Dr. Di Vito.
Meanwhile, Jacopo Zucchi’s canvas shines again on the ceiling of the Sala delle Carte Geografiche, a proud patient of an avant-garde treatment that can pave the way for restoration. green of many works of art.