The art restorer Marco Grassi lives in a typical New York house on the Upper East Side.   His studio on the ground floor is almost like a New York doctor’s surgery.   It is a large room with frames and pictures both on the walls and on the floor, a large work-table and a microscope.   Extremely elegant in tweed suit and dark blue apron, he welcomes me while making an espresso.

The Art Restorer Speaks: “Restoring pictures is like conducting an orchestra.”

What does being a restorer actually mean?

There aren’t many free-lance professional restorers these days, because all the museums have their own arrangements when it comes to conservation.   The New York Metropolitan, for example, has had a system of this kind since the 1930s.

And in Italy?

In Italy there’s the state, the regions and the provinces, as well as the School of Restoration in Venaria, the Hard-Stone Workshop in Florence, the Institute of Restoration in Rome and so on.

And what about you?

I’m a son of art.   My father and grandfather were antiquarians in Florence who worked with legendary characters like the businessman Joseph Duveen, who sold so many masterpieces of early art to the great museums and to American collectors.   My father and grandfather were also friendly with famous figures like Berenson and collectors such as the Contini Bonacossi.

When did you come to America?

The first time was in 1945 with my parents, because my mother was American.   Post-war Italy had been reduced to a country from the year dot, but in America my father was able to set up on his own.   I went to school here and did my military service here, then was overtaken by a terrible homesickness for Italy.   I was 22 or 23 when I went back and I began in 1959 by working at the Uffizi in Florence, followed by two years at the Central Restoration Institute in Rome, and I also studied in Zürich.   But I have never taken a degree – restoration is not like medicine.   I opened a private studio in Florence in 1961 and my father’s friends began giving me work.

And you made a name for yourself?

I was lucky.   In 1964 Baron von Thyssen, the greatest collector in the world at that time, called at my studio.   He asked me to restore a bust by Mino di Fiesole which turned out to be a forgery.   I studied it very thoroughly and assembled all the evidence  that proved it was not authentic.   Then we talked about pictures, and Thyssen invited me to come and see his collection at Castagnola, on Lake Lugano.   I went there, and he asked me to work for him: I was 30 years old at the time and the idea went to my head, but my father advised me to refuse. “Better to be a “visiting conservator” he said.   Thyssen accepted this, so then I divided my time with six months in Lugano and six in Florence.

What major restorations did you do?

The one picture printed indelibly in my mind is a crucifixion by Ugolino da Siena that  in fact belonged to Thyssen.

Do you need an exceptionally good knowledge of the history of art and painting in your job?

Restoration is a craft, a science, very much like a love of words.   Similar to conducting an orchestra.

How do you detect a forgery?

That needs experience and a good eye, and then of course there’s radiography.   I’ve discovered many forgeries, but no one makes them any more now.   The great forgers of Italian paintings were virtually finished by 1900.

What about all the Mona Lisas circulating the world?

Those aren’t forgeries, they’re copies that belong to the time when they were painted.

Are there many forgeries in museums in Italy?

There may be some contemporary copies, but in general Italian museums don’t buy many pictures.

How are attributions made?

That’s the most difficult thing of all.   I’m not a critic myself, and I’m not qualified to decide whether, for instance, a particular picture merely comes from the school of Pinturicchio, or was actually painted by Pinturicchio himself.

How would one set about buying an Old Master?

Mostly by auction or private contact.   Old Masters are relatively cheap, because they are unfashionable and give rise to problems of conservation and identification.   Before the Impressionists it can be difficult to be certain about who painted a picture, but after that it gets easier because so many authoritative catalogues exist.   Another problem is that early art favours religious subjects and not everyone likes having a crucifixion in their home.   If people have two or three million dollars to spend, they’d rather buy a Picasso.

What do you think about the restoration of the works by Piero della Francesca being exhibited at the Metropolitan?

Apart from the ‘Madonna di Senigallia’, which is in perfect condition, they have suffered damage typical of early paintings that have lost a degree of lustre because of too much cleaning, but of course there can be no two opinions about the quality of Piero della Francesca himself!

Have any great masterpieces passed through your hands?

Yes.   Paintings by Rembrandt and Holbein, though in my opinion nothing can equal the art of Siena in the first half of the fourteenth century.   If I could have a dream come true, it would be to own the “Annunciation” by Simone Martini now in the Uffizi.

How do you set about doing a restoration?

You have to let the picture itself tell you what to do.   And sometimes it is best to do nothing at all.