Fresco
As I have mentioned elsewhere (The Northern Renaissance and Chancellor Rolin), I was educated at university to believe that European Renaissance art had its roots in Italy and, most particularly in Florence. That it began with Giotto in the Arena Chapel and the re-discovery and promotion of single point perspective by Brunelleschi and Alberti which manifested itself early on in the painting of Masaccio. All this developed within the relatively democratic freedom of Florence and was then encouraged by the patronage of the Medici family in the “New Athens.”
In my own, subsequent, reading I was to discover that this was only one half of the story – at least in the world of painting – and that similar leaps forward were being made in the Burgundian North of Phillip the Good (which included all of what are now called the “low countries” of Belgium and Holland) by artists like the brothers Van Eyck and Rogier Van der Weyden. Here the driving force seems to have been less the “Ad Fontes” (back to the roots) movement in search of the classical past and more an extraordinary upsurge in commerce and wealth and a resulting desire for luxury goods that took the patronage of the arts from the hands of the aristocracy and the church and placed it in the hands of a new and burgeoning middle class. The result of this was the creation of a large swathe of professional artists doing a roaring business.
As I said, I have written about this elsewhere, but what I did not include and wish to detail here is that there was also another distinctive difference, at first, between the art of the North and the South. And that difference was that in the South (and we are, again, mostly speaking about Florence and then Rome), the “painting” that we are referring to – from Giotto to Michelangelo and Raphael – was almost exclusively Fresco while in the North (even before being perfected by Jan Van Eyck) the painting was in “oils.” The reasons for this were many but one of the most important was that Northern art –unlike Florentine art – had a massive export market. And Fresco is not (easily) portable.
Now a whole book could be written on this cause-and-effect topic (art as a luxury good or an early form of conspicuous consumption) but that is not my interest here. Here I would like to take anyone interested on a brief tour of the fresco itself, because I have discovered that most people – even those who have seen the Sistine Chapel in person – haven’t the foggiest idea about what a fresco is, how they were (are) made and what they are capable of showing. So, let’s start at the beginning.
Fresco is a very ancient technique – perhaps one of the oldest painting techniques. It was used by the ancient Minoan civilization on Crete going back to at least 2000 BCE.
It was known by the ancient Egyptians and the early Hindu civilizations and it was used in the early Christian world as well as in the Muslim world. It became very popular in the later Roman Empire and the dominant visual art in the Byzantine Era from which it spread west to Europe – particularly Italy, where it also became the dominant visual art. It is Italian fresco that we will look at in detail.
There three main types of fresco technique: Buon or true fresco, Secco and mezzo-fresco. Buon fresco is the most common fresco method and involves the use of natural pigments mixed with water (that is, without a binding agent, like oil) painted on a thin layer of wet, fresh, lime mortar or plaster called intonaco. The pigment is absorbed into the plaster as it dries and becomes part of the plaster, part of the wall or ceiling. It is quite durable and can be cleaned and even painted over – which it sometimes is. Secco fresco (type two) is done onto dry plaster and therefore requires a binding medium, (egg tempera, glue or oil) to attach the pigment to the wall; Secco is used for fine, detailed work and today for restoration work on frescos. Occasionally secco was used experimentally (or in error) as a replacement for buon fresco, as in the famous mural painting known as The Last Supper by Leonardo Da Vinci. Even Leonardo made mistakes. The third method, Mezzo-fresco, involves painting onto almost but not quite dry intonaco so that the pigment only penetrates slightly into the plaster. By 1600 mezzo had largely replaced buon fresco on interior murals and ceilings.
Buon Fresco is the most difficult of the techniques and naturally produces the best results, so let’s look at the process in some detail.
The wall to be painted is covered by a rough layer of mortar called arriccio. This is a rough layer to which the painted layer will adhere. The night before, the wall to be painted is dampened in preparation for the arriccio, to keep it moist and fresh. The next day, the image to be painted is outlined on the applied arriccio with charcoal and then the outline is darkened in with an ochre pigment called a sinopia.
This is covered over thinly with the smooth plaster, or, intonaco. This is all done to the size of an area that the painter thinks can be painted in one day’s work. Otherwise, it would dry unpainted and would then have to be removed and applied again, wet. Usually, individual figures or structures will be done in one day. Sometimes, if they are large, they would have to be done in sections.
The intonaco is often mixed by a specialized assistant to the painter – a muratore –since the mixing of the intonaco was tricky because one of the ingredients was unslaked lime which was very caustic. On top of the intonaco the artist painted the day’s painting and then it was left to dry. There are a number of reasons why this process could fail. Since it was a chemical process there could be unusual color alterations. The process could also be altered by the relative humidity in the room. Rainy days were always a problem for frescos – colors could migrate in the wet intonaco. One of the reasons that Michelangelo struggled for so long with the ceiling of the Sistine Chapel was that, on rainy days, it leaked.
As result of these difficulties, many painters would return to the work and over-paint the dried work – secco – where a binding element (such as egg tempura, or glue) would be used. This becomes a problem with restoration: as you will see later on with the Sistine ceiling. Let’s just say that buon fresco was prized over secco because it required great skill – and greater luck. The buon fresco painter was considered to be bolder, more dynamic, a lover of the challenging.
Because the sinopia disappeared under the painting the artist often restricted themselves to fairly simple and repetitive designs. But as the complexity of painting developed in the 15th century, painters began to use cartons or “cartoons” to retain a copy of the plan of the entire painting. This involved using large sheets of paper each consisting of a day’s painting that was then glued to the other cartoons (edge to edge) to make up the whole work as planned. Each cartoon was scaled up from a sketch by means of the process of “quadrating” or blowing up in scale. The cartoon would be placed on the intonaco then a stylus would be pressed along the lines of the cartoon leaving indentations on the intonaco. Or, the cartoon was placed over the day’s intonaco and small holes would be punched through along the drawing’s lines. Then a pumice bag of powdered charcoal would be tapped along the perforated lines leaving spotted lines representing the shapes of the cartoon (the spolvero technique). Then the painter would paint.
All this complexity led to specialization and the creation of artistic teams. One team would prepare and apply the various plasters; another team – usually led by the artist – would prepare the sketches and cartoons. A third team would grind and prepare the pigments. The use of teams allowed popular artists, like Raphael, to work on a large number of commissions – or very large projects – since much of the grunt work was done by others.
By the 17thcentury work was speeded up even more by working on semi-dry plaster: mezzo-secco. This allowed painters (beginning with Andrea Pozzo (1642-1709) to paint large areas rapidly. And as oil paintings gained in popularity, frescos began to be restricted more and more to ceilings and vaults and thus took far longer to achieve with the old methods, so mezzo took over.
The pigments used in fresco were famous for their luminosity and this was so important a feature in fresco painting that the rule was one brush per mixed colour. The pigments were mostly made from natural, local materials, sometime discovered by the painters themselves or from minerals and medicines purchased in pharmacies. For this reason, most fresco painters were members of the guild of physicians and pharmacists. Special colours were made from semi precious gems like ultramarine blue which was made from lapis lazuli found only in Afghanistan. Another blue came from azurite. The root of the madder plant produced carmine red which was both a pigment and a medicine.
Some other popular colors were: sienna – iron-rich clay from Sienna, a yellow-brown; terra verde – a green from the soil of Verona; ivory black – made from charring ivory; smalt – grinding glass mixed with cobalt, a blue; and gold – made with … gold, and very expensive.
The creation of frescos was, clearly, a business. The fresco master was not only an artist, he was also the manager of a studio with a number of employees. It was a complex and precise undertaking that required a great deal of organizing and preparation before the actual painting could start. The design had to be devised, sketched and then upscaled; the colours had to be prepared, the plaster applied, and the wall made ready for painting. Some four to six men could be at work on the scaffold at one time, amid pots of colours, buckets, brushes, sacks of sand and limestone. The Hollywood image of Michelangelo alone on his back painting the ceiling was just invention. He was never alone and he didn’t lie down. But he did help change the status and nature of the artist.
Painting had a low status in the Middle Ages in the sense that it was considered just another craft and as such was not classed with the higher-ranking arts – like poetry. Starting with Brunelleschi, Ghiberti and Alberti, artists began to asset their personalities and the value of their Art. One of the things that helped promote this change was the use of very public competitions for public art contracts. Beginning with a plan for the Dome of Santa Maria Fiore Cathedral (the Duomo) in Florence and continuing with the new doors for the Baptistry of that Cathedral to the epic civic fresco battle between Michelangelo and Leonardo da Vinci.
The development of the distinctive artistic features of the Italian Renaissance showed themselves most clearly in fresco before expanding into the oil techniques imported from the North. The most obvious example of this was the use of linear perspective to give the illusion of depth. In Italy this principle was recovered from classical texts. In the north, painters like Van Eyck used other techniques to give similar results.
The principle of linear perspective was first laid out by Euclid and recovered from the works of Euclid and expanded by the Arabian mathematician, Alhazen (965-1040). Alhazen’s work was translated into Latin in 1200 and available in Italy around the end of the 14th century. Its first credited use was by Brunelleschi and it was popularized by Leon Baptista Alberti in his Treatise on Painting (1435), which was dedicated to Brunelleschi, but you can see inklings of it in Giotto’s (1267-1337) work and the full effect is clear in Masaccio’s Holy Trinity.
It was later used in extreme ways by painters a s varied as Caravaggio and Rembrandt.
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In later fresco, this technique became very useful with frescos on ceilings or in cupulas and could produce works which which might not be great paintings but were visual wonders. Here are some examples:
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And now two supreme wonders in fresco:
Now, before we leave the subject, a not-so-brief afterthought. While all of this might seem just interesting academics, it has some weighty real-life applications. Consider the case of the most famous fresco in the world: the ceiling of the Sistine Chapel (partially shown above). The work was done from 1979 to 1994 by a team led by Gianluigi Colalucci, Maurizio Rossi and Piergiorgio Bonetti. The work was controversial for numerous reasons – not the least because it was paid for (in part) by selling the exclusive filming rights to the Nippon Television Network who were very reluctant to release what they had shot.
But there were larger issues that surrounded the “restoration” The ceiling clearly needed something done for several reasons. First, tourism had increased by an extraordinary amount and the carbon dioxide and humidity from the crowds had had a large impact on the ceiling. I have been there twice and both times it was absolute bedlam. Second, the Chapel is, well, a chapel and so there are regular services in there and have been since it was painted in 1481. The candle soot alone had coated the ceiling and had never been adequately dealt with. Third, the roof had leaked since it was built, before the arrival of Michelangelo, and although brass pins had to used to stabilize the intonaco there were concerns that new cracks had been appearing.
What was troubling was that there were a number of surviving members of the team that had done the last restoration in the 1930’s and they claimed most vociferously that Michelangelo had overpainted a secco in many parts of the work but the new restoration team denied this and were preparing to use a chemical cleaning agent that would do no harm to the buon fresco and would clean the ceiling of all the smoke, greases and stains of 500 years of usage of the building – but would also remove any secco painting. And the fight was on.
In the end the restorers used their cleaning agent and there was one very positive result. The over-all appearance and coloration of the ceiling was miraculously improved. So much so that some art historians said that the art history books needed to be re-written to speak of Michelangelo’s bold use of colour. The Pope was hugely impressed with the new ceiling.
On the other hand, it was equally clear that in many places that Michelangelo had clearly worked in secco and that work – particularly in the architectural detail – was lost forever. Also, the artist consistently used a “black wash” in secco to give depth and shadow. That, too, is gone forever. Jonah’s “great fish” has receded into a large carp without the black wash effect.
There are many other examples of what has been lost but the greatest of them all has been the disappearance of many eyes. Again, there are numerous examples of this but I will show you one of the most obvious – a detail of the spandrel of Jesse, before and after cleaning. The eyes are gone.
The rest I will leave to Peter Layne Arguimbau writing in 2007:
Have you ever felt that some things never fade and remain an inspiration for all time? That was the Sistine Chapel, now chemically stripped down of divine inspiration and looking shockingly out of place. ... It is the duty of the restorer not to alter the intent of the artist, but the scientist cannot help himself. Who cares if Colalucci discovered Michelangelo as a colorist and can explain the Colorist trends of Pontormo and Rossi. His job is to make sure the thing is stuck on there and leave it alone. In comparing before and after photos there is much proof that Colalucci removed 'a secco' passages and left many areas sketchy and thin. Proof of one single change of the artist's intent is negligence of which there are many.
Michelangelo’s great work has been diminished and cannot be reclaimed.
