fresco painting definition

"fresco painting is the technique that uses grind pigments diluted in water over wet plaster made of quick lime and sand" 

"la pintura al fresco es la técnica que utiliza colores molidos y diluidos en agua sobre un estrato de mortero de arena y cal fresco"

CENNINO CENNINI-The book of art 

CHAP. 67. The manner of painting on walls, that is, in fresco, and of colouring or painting the flesh of the faces of young persons. In the name of the most Holy Trinity, I will now put you to colouring. I begin first with painting on walls, and shall teach you step by step the manner in which you ought to proceed. When you are going to paint on walls, which is the most delightful and charming kind of work that there can be, procure, in the first place, lime and sand, both of them well sifted. If the lime is very rich and fresh, it will require two parts of sand, the third of lime. Grind them well together with water, and grind enough to last you fifteen or twenty days. Let it rest for some days till it be quite slaked; for if any heat remains in it, it cracks the plaster (intonaco). When you are going to plaster, first sweep the wall, and wet it well you cannot wet it too much; and take the well - stirred lime, a trowelful at a time, and spread it over once or twice, till the intonaco becomes quite even on the wall. Afterwards, when you are going to work, remember to make the surface of the mortar quite rough (bene arricciato) with a good tooth (rasposd). Then, according to the subject or figures you have to make, if the intonaco is dry, take some charcoal, and design and compose, and take every measurement carefully, first striking one ...



Of Painting on the Wall, how it is done, and why it is called Working in Fresco.

81. The Fresco process.

OF all the methods that painters employ, painting on the wall is the most masterly and beautiful, because it consists in doing in a single day that which, in the other methods, may be retouched day after day, over the work already done. Fresco was much used among the ancients, and the older masters among the moderns have continued to employ it. It is worked on the plaster while it is fresh and must not be left till the day's portion is finished. The reason is that if there be any delay in painting, the plaster forms a certain slight crust whether from heat or cold or currents of air or frost whereby the whole work is stained and grows mouldy. To prevent this (the wall that is to be painted must be kept continually moist; and the colors employed thereon must all be of earths and not metallic and the white of calcined travertine) There is needed also a hand that is dexterous, resolute and rapid, but most of all a sound and perfect judgment; because while the wall is wet the colors show up in one fashion, and afterwards when dry they are no longer the same...



The fresco plaster is made of sand and quick lime.


El enlucido para el fresco está compuesto por arena y cal.


The plaster must be extended with a trowel, till the surface is smooth.


El enlucido se extenderá con paleta o llana hasta que la superficie quede lisa.


Spolvero is the method to transfer the drawing from the paper to the plaster.

Soplvero es la técnica que se utiliza para pasar los dibujos del papel al enlucido.


The design is recover with the dots of pigment from the "spolvero" technique.


 El dibujo se recupera siguiendo los puntos dejados por la técnica del "spolvero".



Each day, the plaster must be extended over the wall and painted in about 8 hours, depending of the temperature and humidity conditions, otherwise the plaster must be removed or retouched with dry techniques. 

Cada día se enluce el soporte sobre la pared y se tiene que pintar en 8 horas más o menos, dependiendo del grado de humedad y temperatura, si no se termina hay que picar la superficie o retocar la pintura con técnicas en seco.



The colors are just  grind pigments diluted on water. The pigments remain into the plaster on the chemical reaction call carbonation, produced by the lime.

Los colores son pigmentos molidos diluidos en agua. Los pigmentos quedan dentro del enlucido en una reacción química llamada carbonatación.