Note 217 — Chapter VIII · (XXII.)

The matter in our § 87 was added in the edition of 1568. Though Vasari declared so unhesitatingly for fresco as the finest of all processes of painting, he tells us that he used oil for a portion of his mural work in the Palazzo Vecchio at Florence, when he prepared it for the residence of Duke Cosimo, and we shall notice later his praise of tempera (postea, p. 291). Vasari describes how he painted in oil on the walls of a refectory at Naples (Opere, VII, 674), and gives us an interesting notice of his experiments in the technique about the year 1540 at the monastery of the Camaldoli, near Arezzo, where he says ‘feci esperimento di unire il colorito a olio con quello (fresco) e riuscimmi assai acconciamente’ (Opere, VII, 667). The technique required proper working out, for it was not a traditional one.

The most notable instance of its employment before the end of the fifteenth century is in the case of the ‘Last Supper’ by Leonardo da Vinci at Milan. A commission of experts has recently been examining the remains of this, the most famous mural painting in the world, and has ascertained that the original process employed by Leonardo was not pure oil painting but a mixed process in which oil played only a part. The result at any rate, as all the world is aware, was the speedy ruin of the work, which now only tells as a design, there being but little of its creator’s actual handiwork now visible.

Some words of the Report are of sufficient interest to be quoted. ‘Pur troppo, dunque, la stessa tecnica del maestro aveva in sè il germe della rovina, ben presto, infatti, avvertita nelle sue opere murali. Spirito indagitore, innovatore, voglioso sempre di “provare e riprovare” egli voile abbandonare i vecchi, sicuri e sperimentati sistemi, per tentare l’ esito di sostanze oleose in miscela coi colori. Perchè nemmeno può dirsi ch’ ei dipingesse, in questo caso, semplicemente, ad olio come avrebbe fatto ogni altro mortale entrato nell’ errore di seguire quel metodo anche pei muri. Egli tentò invece cosa affato nuova; poichè, se da un lato appaiono tracce di parziali e circoscritte arricciature in uso pel fresco, dall’ altro, la presenza delle sostanze oleose è accertata dalla mancanza di adhesione dei colori con la superficie del muro e dalle speciali screpolature della crosta o pelle formata dai colori stessi, non che dal modo con quale il dipinto si è andato e si va lentamente disgregando e sfaldando.’ Bollettino d’ Arte del Ministero della Pubblica Istruzione, Roma, 1907, I, p. 17.

Another famous instance of the use of oil paint in mural work about a generation later is to be found in the Sala di Costantino in the Vatican, where Raphael’s pupils have left two of the decorative figures by the side of the Popes executed in that medium. One (Urbanity) is close to the door leading to the Chapel of Nicholas V, the other is on the wall containing the battle, and is in better preservation than the first which is covered with wrinkles. The oil paint gives a certain depth and richness of effect, but there is the fatal disadvantage that the painting does not look a part of the wall as is the case with work done in fresco. The fresco is really executed in the material of the ground, whereas oils and varnishes have nothing in common with lime and earths, and the connection of structure and decoration is broken. One of the most successful pieces of work of the kind is the painting of ‘Christ at the Pillar’ by Sebastian del Piombo in S. Pietro in Montorio at Rome. The work, which is executed on a cylindrical surface, is rather shiny, an appearance which in mural painting is to be avoided, and it has darkened somewhat, though this defect is not very apparent and the experiment has on the whole succeeded well. Vasari’s Life of Fra Sebastiano contains a good deal of information about this particular technique, which was essayed in the later age of Italian painting more often than is sometimes imagined. It needs hardly to be said that this oil painting on the actual plaster of the wall is a different thing from the modern process of painting on canvas in the studio and then cementing the completed picture on to the wall. Mural painting on canvas was introduced by the Venetians in the fifteenth century, for at Venice atmospheric conditions seem to have been unfavourable to the preservation of frescoes, and the Venetians preferred canvas to plaster for their work in oils. It would be interesting to know whether the canvas was ever fixed in situ before the painter commenced operations, as from the point of view of the preservation of decorative effect this would be of importance. Vasari’s story about Tintoretto’s proceedings at the Scuola di S. Rocco (Opere, VI, 594) is evidence that canvases were painted at home and put up on walls or ceilings when finished. Of course if a wall be covered with canvas before the painting begins the canvas is to all intents and purposes the wall itself, grounded in a certain way.