Techniques and pigments

MURAL PAINTINGS

The word " fresco " is often used improperly. What may seem a purely technical distinction enables us to understand why some details (eyes, cheekbones, lips) have all but disappeared, whereas the rest is in a relatively good state of preservation. Two techniques were used: fresco and distemper painting. In the churches of the Pays de la Loire, both techniques were often used to paint a scene: fresco for solid tints and backgrounds, distemper for added details.

1) Technique de la Fresque (fresco)

1) Tecnica dell'affresco (a fresco)

1) The fresco technique

The walls supporting the frescoes are always made of brick or stone. They must be clean, sound and waterproof since dampness is the main enemy of "a fresco" painting. To prepare a wall before painting a fresco, the mortar must adhere to it perfectly. If it is not the case, the wall is covered with a coarse rendering, about 2 inches thick. The stone mason plays an important part. He prepares the support which must be perfect for the paint to hold. When the wall is ready, it can be coated. The coatings are applied evenly and their number varies (usually three). The first coating (arricio) is coarser than the last one (intonaco). The mortars used for the arricio are composed of river sand and slaked lime. The coating dries quickly. The fresco painter has only a few hours to complete his work. In the past, the outlines of the fresco was transferred freehand on to the arricio with red Sinope. Finally, the painter can paint the fresco. At this final stage, the intonaco must be elastic to absorb the coat of paint. The brushes used are generally made from the hairs of martens (sable hair brushes), mongooses or oxen's ears. Sometimes natural sponges are used. A painting session lasts from 4 to 6 hours. After that, the mortar is dry and can no longer be painted on. No solvents are used, all the binders are based on whitewash or limewater.

For a long time, it was thought that the pigments were absorbed by the still wet mortar, which explained the durability of true frescoes. We now know that a chemical reaction explains the durable fixation of the pigments. The calcium hydroxide (Ca(OH)2 contained in the slaked lime reacts with the carbon dioxide (CO2) contained in the air. Besides the evaporation of the water, the reaction produces a very resistant coating of crystallised calcium carbonate (CaCO3) on the surface of the mortar, thus gradually "trapping" the pigments.

2) Peinture à la Détrempe (secco)

2) Distemper

2) Pittura a tempera (a secco)

The term Fresco secco and its variations are inaccurate and should be not be used since they are self-contradictory and do not make sense. In the Art and Architecture Thesaurus (AAT) the term Secco is preferred to non-accepted terms: dry fresco, fresco a secco, fresco secco, fresco-secco and secco-fresco.

Technique of applying colours which are not resistant to lime over an undercoat, putting the finishing touches on a fresco after it has hardened. Tempera is mixed with adhesive such as gum arabic, casein or animal skin glue or applied over a thin coating of adhesive painted on the wall after dampening down the plaster. (Also used to paint entire murals on dry plaster. The results are not as durable or brilliant as with Buon Fresco.)

1) Pintura al fresco.

Por pintura mural al fresco se entiende toda pintura mural que se ejecuta sobre una preparación al fresco, es decir, que el “intónaco” o el revoco debe estar húmedo para que los pigmentos aplicados sean aglutinados y absorbidos por la carbonatación de la cal.

2) Pintura a seco.

Por pintura mural a seco se entiende toda pintura ejecutada sobre una preparación o revoco seco y cuyos pigmentos se fijan al muro por medio de un aglutinante en el que van disueltos o mezclados. Los aglutinantes más comunes han sido: la cal, témpera y óleo.

3) Pintura mixta.

Se define así a la pintura mural que como base está realizada al fresco y es completada o finalizada a seco.

3) XVIIIème, XIXème et XXème siècles:

3) 18th, 19th and 20th centuries:

3) Diciottesimo, diciannovesimo e ventesimo secolo:

Discovered in the late 18th century, potassium silicate was used experimentally in the 19th century and industrially until the mid-20th century. At Saint-Martin-du-Limet, count de Galembert - a French archeologist and mural painter, used it in a very special way: he diluted and heated this potassium silicate according to the coloured pigments with which he mixed it. The present synthetic paints do not require any particular skill but seem to be much less durable

THEMES ET TOPOGRAPHIE DES PEINTURES MURALES

THEMES AND TOPOGRAPHY OF MURAL PAINTINGS

TEMATICHE E TOPOGRAFIA DEI DIPINTI MURALI

Until the 11^th and 12^th centuries, the interior of churches was probably entirely covered with mural paintings, as in Saint-Savin-sur-Gartempe. Thematically and topographically, the paintings can be divided into two categories: theophanies (visible manifestations of God) on the walls and vault of the apse and narrative cycles (stories from the Bible or the Lives of Saints) on the other walls or vaults.

1) Vault of the apse - Volta dell'abside:

In most Romanesque churches, the vault of the half-domed apse is adorned with a Christ in majesty, that is to say sitting on a throne surrounded or inscribed in an almond-shaped glory known as a mandorla. Christ is sometimes replaced by a Virgin in majesty. Generally, the mandorla is surrounded by the animals of the Apocalypse (the four Living Creatures) symbolising the four Evangelists. This Tetramorph represents a man or angel (Matthew), a lion - sometimes winged - (Mark), an ox (Luke) and an eagle (John). (see Eglise de Saint-Céneri)

2) Vault of the choir, triumphal arch - Volta del coro, arco trionfale.

The vault of the choir is sometimes decorated with the Mystic or Christic Lamb, the twenty-four Elders of the Apocalyse or a Zodiac. On the intrados of the the triumphal arch of a handful of churches, scenes representing the activities of the different months of the year have been painted in the form of a calendar. (see Montoire: Saint-Gilles - Château-Gontier - Sargé-sur-Braye and Saint-Christophe-sur-le-Nais).

3) Walls of the nave - Muri della navata

The paintings adorning the walls of the nave or of the aisles represent scenes from the Old and New Testaments. The Old Testament is often represented on the walls of the side-aisles (less visible) and the New Testament on the upper parts of the nave (more visible). For example, Saint Christopher, which travellers had to see at least once a day in order to avoid sudden death, is often painted larger than life (he was a giant) on the northern wall of the nave, near the entrance to the church. (see Le Lion d'Angers)

4) Reverse of the western façade - Retro della facciata ovest