The question of the exact technique of the van Eycks, in its relation to the oil practice before their time, is one that has occupied many minds, and is not yet satisfactorily settled. Most of those who have enunciated theories on the subject have proceeded by guess-work, and have suggested media and processes that may possibly have been used, but for the employment of which there is no direct evidence. The most recent suggestion is that of Principal Laurie of Edinburgh, and this is founded on scientific analysis. The experiments with oils and varnishes and other media, which this investigator has been carrying on for many years, have taught him that the most secure substance for ‘locking-up’ pigments as the phrase goes, that is for shielding them from the access of moisture or deleterious gases, is a resin, like our Canada balsam, that may be used as a varnish or painting medium when dissolved in an essential oil. As he believes he can detect in the van Eycks’ extant pictures pigments that would only have lasted had they been shielded by a preparation of the kind, he conjectures that the use of a natural pine balsam, with probably a small proportion of drying oil and rendered more workable by emulsifying with egg, may be the real secret of which so many investigators have been in search. For example, the green used for the robe of John Baptist and other figures in the ‘Adoration of the Lamb’ at Ghent can be matched, as we lately found by experiment, with verdigris (dissolved in pine balsam which is a much finer green than verdigris ground in oil) and yellow ochre or orpiment, and the only known way of rendering verdigris stable is to dissolve it in these pine balsams, according to a recipe that is actually preserved in the de Mayerne MS., which Berger has lately printed in full in the fourth Part of his Beiträge.
Be this as it may, one thing is certain, that the oil painting of the van Eycks and other painters of the early Flemish school did not differ greatly if at all in its artistic effect from the tempera that had preceded it, and that is described in the last note. Oil painting, in the sense that we attach to the term, is really the creation not of the Flemings, nor of the Florentines and other Italians who were the first to try experiments with the new Flemish process, but of Giovanni Bellini and the other Venetians who adopted the oil medium in the last quarter of the fifteenth century. According to Vasari, ante, p. [229], and Life of Antonello da Messina, Opere, II, 563 f., it was the last named artist who acquired the secret of the invention of van Eyck through a visit to Flanders, and brought it to Venice. Vasari has been proved to be wrong in the chronology he gives of the life of Antonello, who was born about 1444 and was therefore much younger than Vasari makes him, and many critics have been disposed to relegate his whole account of the Sicilian painter to the realm of myth. The most recent authority on the subject however, Dr von Wurtzbach, in his Niederländisches Künstler-Lexicon, vindicates Vasari’s accuracy in the main points of the visit to Flanders and the introduction of the new process at Venice, which event may be fixed about 1475. It was taken up with avidity by the Bellini and by other Venetians of the time, and it is to the younger Bellini more than to any other painter that is due the apprehension of the possibilities latent in the oil medium. Giovanni Bellini began to manipulate the oil pigments with a freedom and a feeling for their varied qualities of which earlier oil painters had possessed little idea, and the way was prepared for the splendid unfolding of the technique in the hands of Giorgione, Palma, and Titian.
ENRICHED FAÇADES.
[§§ 90–92, ante, p. [240] f.]
The external decorations, of which Vasari writes in chapters XI, XII, and XIII of his ‘Introduction’ to Painting, have come down to us in a very dilapidated condition, but there are still to be seen specimens of all the work he there describes, as well as of the decorative carvings in stone noticed in the ‘Introduction’ to Architecture, under the head of Travertine (at Rome) § 12, Istrian stone (at Venice) § 15, and Pietra forte (at Florence) § 17; ante, pp. [51], 56, 60. The most common technique is monochrome painting ‘a fresco’ on the plaster, and a good deal that passes as sgraffito is really only painted work in which there is no relief. One of the best existing displays is that on the façade of the Palazzo Ricci, at Rome, a little to the west of the Palazzo Farnese. Here on the top floor are painted trophies of armour in bronze colour (ante, p. [241]) with grotesques (ante, p. [244]) in yellow and brown on the story below. On the piano nobile there is a frieze of figures in grisaille monochrome, with some single figures on a larger scale between the windows. Above the door is another frieze of figures on a black ground. More extensive, but less varied and not so well preserved, are the figure compositions on the back of the Palazzo Massimi, in the Piazza dei Massimi, at Rome, where the whole wall is covered with figure monochromes on a large scale on dark grounds. There are many more fragmentary specimens, as in the Via Maschera d’ Oro, No. 7; the Via Pellegrino, No. 66, etc. The work of Maccari, Roma, Graffiti e Chiaroscuri, Secolo XV, XVI, gives a large collection of reproductions of work that has now to a great extent perished.
Sgraffito-work, in which the effect is produced by differences of plane in the plaster itself (see ante, p. [243]), resists the weather much better than mere painting, but it takes longer to execute and was not so much used as the more rapidly wrought fresco. The Palazzo Montalvo, in the Borgo degli Albizzi at Florence, offers a good example of a compromise. The work, at any rate in the lower part, is not true sgraffito as the plaster in the backgrounds is not scraped away, but the outlines of the figures and ornaments are marked by lines incised in the plaster, the brush, with light and dark tints, accomplishing the rest. On the other hand the house of Bianca Capello, 26 in the Via Maggio, is decorated in the true sgraffito technique as described by Vasari, ante, p. [243]. The same may be said of a house in Rome, Via Maschera d’ Oro, No. 9, where the difference of the two planes of plaster is about an eighth of an inch. This work is clogged up with buff lime-wash and would be worth cleaning, as it seems in fair preservation.
Of modelled stucco figure designs and grotesques the Cortile of the Palazzo Spada, near the Campo di Fiore at Rome, presents the most extensive display. A more interesting piece of work will however be found not far away in the Via de’ Banchi Vecchi, Nos. 22–24, the house of the goldsmith Pietro Crivelli of Milan, of the first half of the sixteenth century. Here between the windows of the first floor are boldly designed trophies of arms carved in travertine, while between and above the windows of the second floor there are figures and grotesques effectively modelled in stucco. These are outlined with an incised line in the stucco and there is no colour. For free but not over-florid Renaissance enrichment the façade is noteworthy. The abundant stone carving at Florence in the form of the ‘stemmi’ has been already referred to, ante, p. [61].
STUCCO ‘GROTESQUES.’
[§ 92, Grotesques or fanciful devices painted or modelled on walls, ante, p. [244].]
Vasari touches on the subject of plaster work in all three ‘Introductions,’ to Architecture (§ 29), to Sculpture (§ 73) and to Painting (§ 92). In the former passages he deals with the material itself and with what may be called its utilitarian employment; in the last he has in view the artistic forms into which the material can be moulded, and which he calls by the curious name ‘grotesques.’ What these ‘grotesques’ are will presently be seen, but it is worth while first casting a glance back on the artistic use of plaster in its historical aspects.