From this pigment, the underdrawing acquired its name, the sinopia. On top of this first, rough layer of plaster, a second layer is added, called the intonaco. This is the final layer, and would be smoothed and perfected as the painting surface. Buon fresco technique consists of painting in pigment mixed with water on wet, fresh, lime mortar or plaster (intonaco). Due to the chemical makeup of the plaster, a binder is not required, as the pigment mixed solely with the water will be enough to bind the pigment to the wall. The pigment is absorbed by the wet plaster; after a number of hours, the plaster dries, and the pigment dries as well, a part of the wall. One of the first painters to use this technique was the Isaac Master in the Upper Basilica of Saint Francis in Assisi.

A secco painting, in contrast, is done on dry plaster. The pigments thus require a binding medium, such as egg, to hold the pigment to the wall. Generally, buon fresco works are more durable than a secco works. Historically, the a secco technique was used more often for final touches or to touch-up mistakes made in a buon fresco work.

Buon frescoes are difficult to create because of the deadline associated with the drying plaster. Generally, a layer of plaster will require ten to twelve hours to dry; ideally, an artist would begin to paint after one hour and continue until two hours before the drying time. Thus, an artist would need to know exactly how much s/he could paint in those hours, before the plaster dries: this area is called the giornata ("day's work"). Once a giornata is dried, no more buon fresco can be done without removing the dried plaster from the wall-- a task usually requiring a crowbar or other sharp instrument-- and starting over. Hence the use of a secco to repair minor mistakes or to add finishing touches.

In a wall-sized fresco, there may be ten to twenty giornate, or separate areas of plaster. After centuries, these giornate (originally, nearly invisible) have become visible, and in many large-scale frescoes, these divisions are visible from the ground. Additionally, the border between giornate was often covered by a secco frescoing, which has since fallen off.

Frescoes in history

The earliest known examples of frescoes done in the Buon Fresco method date at around 1500 BC and are to be found on the island of Crete in Greece. The most famous of these, The Toreador, depicts a sacred ceremony in which individuals jump over the backs of large bulls. While some similar frescoes have been found in other locations around the Mediterranean basin, particularly in Egypt and Morocco, their origins are subject to speculation.

Some art historians believe that fresco artists from Crete may have been sent to various locations as part of a trade exchange, a possibility which raises to the fore the importance of this art form within the society of the times. The most common form of fresco was Egyptian wall paintings in tombs, usually using the a secco technique.

Frescoes were also painted in ancient Greece, but few of these works have survived. In southern Italy, at Paestum, which was a Greek colony, a tomb containing frescoes dating back to 470 BC was discovered. These frescoes depict scenes of the life and society of ancient Greece, and constitute valuable historical testimonials. One shows a group of men reclining at a banquet and another shows a man diving into the sea.

Roman wall paintings, such as those at Pompeii and Herculaneum, were completed in buon fresco. One of the rare examples of Islam fresco painting can be seen in Qasr Amra, the desert palace of the Umayyads in the 8th century.

Late Roman Empire (Christian) 1st-2nd century frescoes were found in catacombs beneath Rome and Byzantine Icons were also found in Cyprus, Crete, Ephesus, Capadocia and Antioch. The late Medieval period and the Renaissance saw the most prominent use of fresco, particularly in Italy, where most churches and many government buildings still feature fresco decoration.

Andrea Palladio, the famous Italian architect of the 16th century, built many mansions with plain exteriors and stunning interiors filled with frescoes. From Wikipedia, the free encyclopedia.