Vasari on Technique | Project Gutenberg

201. Tempera painting has had a far longer history and more extensive use than any other kind. The technique predominated for all kinds of painting among the older Oriental peoples and in classical lands, and was in use both on walls and on panels in Western Europe north of the Alps during the whole mediaeval period, while south of the Alps and at Byzantium it was to a great extent superseded for mural painting by fresco, but remained in fashion for panels till the end of the fifteenth century. After the fifteenth century the oil medium, as Vasari remarks, superseded it entirely for portable pictures, and partly for work on walls and ceilings, but in our own time there has been a partial revival of the old technique. See Note on ‘Tempera Painting,’ postea, p. 291.

The whole question of the different vehicles and methods used in painting at various periods is a difficult and complicated one, and too often chemical analysis fails to give satisfactory results owing to the small amount of material available for experiment. Berger, in his Beiträge zur Entwicklungs-Geschichte der Maltechnik, an unfinished work that has already run to a thousand pages, goes elaborately into the subject, but has to admit that many points are still doubtful. It makes comparatively little difference what particular medium is used in tempera painting, but it is of great importance to decide whether a particular class of work is in tempera or in fresco. In connection with this Berger has reopened the old controversy as to the technique of Pompeian wall paintings, which have been accepted as frescoes, on the authority of Otto Dönner, for a generation past. There are difficulties about Pompeian work and it is well that the question has again been raised, but Berger goes much too far when he attempts to deny to the ancients the knowledge and use of the fresco process. The evidence on this point of Vitruvius is quite decisive, as he, and Pliny after him, refer to the process of painting on wet plaster in the most unmistakeable terms. See Note on ‘Fresco Painting, postea, p. 287.

202. This passage about the early painters of Flanders occurs just as it stands, with some trifling verbal differences, in Vasari’s first edition of 1550. The best commentary on it is, first, the account of the same artists in Guicciardini’s Descrittione di Tutti i Paesi Bassi, first published at Antwerp in 1567, and next, Vasari’s own notes on divers Flemish artists which he added at the end of the Lives in the second edition of 1568 (Opere, ed. Milanesi, VII, 579 f.). He there made certain additions and corrections from Guicciardini, the most noteworthy of which is the mention of Hubert van Eyck, whom Vasari ignores in this passage of the Introduction, but who is just referred to by Guicciardini at the end of his sentences on the younger brother—‘A pari a pari di Giovanni andava Huberto suo fratello, il quale viveva, e dipingeva continuamente sopra le medesime opere, insieme con esso fratello.’ Vasari however in the notes of 1568 goes much farther than this, and, though he does not call Hubert the elder brother, he seems to ascribe to him personally the supposed ‘invention’—‘Huberto suo fratello, che nel 1510 (sic) mise in luce l’ invenzione e modo di colorire a olio’ (Opere, l.c.). ‘John of Bruges’ is of course Jan van Eyck. Vasari writes of him at the end of the Lives as ‘John Eyck of Bruges.’ Vasari’s statement in this sentence is of great historical importance, for it is the first affirmation of a definite ‘invention’ of oil painting, and the first ascription of this invention to van Eyck. As van Eyck’s own epitaph makes no mention of this, and as oil painting was practised long before his time, Vasari’s statement has naturally been questioned, and on the subject the reader will find a Note at the close of the ‘Introduction’ to Painting, postea, p. 294.

203. It was long supposed that this picture was the ‘Epiphany’ preserved behind the High Altar of the Church of S. Barbara, Naples, but Crowe and Cavalcaselle, History of Painting in North Italy, II, 103, pronounce this ‘a feeble and injured picture of the eighteenth century.’

204. Frederick of Urbino (there were not two of the name as Vasari supposes) seems to have had a bathroom decorated with secular compositions by the Flemish master. Facio, whose tract De Viris Illustribus, written in the middle of the fifteenth century, was printed at Florence in 1745, writes, p. 46, of ‘Joannes Gallicus’ (who can be identified as Jan van Eyck) who had painted certain ‘picturae nobiles’ then in the possession of Cardinal Octavianus, with ‘representations of fair women only slightly veiled at the bath.’ Such pictures were considered suitable decorations for bath chambers. There is a curious early example of mediaeval date in the Schloss Runkelstein near Botzen in the Tyrol, in the form of wall paintings round a bathroom on one side of which nude figures are seen preparing to enter the water, while on two other walls spectators of both sexes are seen looking in through an open arcade. The pictures here referred to by van Eyck are now lost, but by a curious coincidence attention has just been directed to an existing copy of one of them, of which Facio gives a special notice. The copy occurs in a painting by Verhaecht of Antwerp, 1593–1637, that represents the picture gallery of an Antwerp connoisseur at about the date 1615. There on the wall is seen hanging the van Eyck, that corresponds closely to the full description given by Facio. The painting by Verhaecht was shown at Burlington House in the Winter Exhibition, 1906–7, and in the ‘Toison d’Or’ Exhibition at Bruges in 1907. See also the Burlington Magazine, February, 1907, p. 325. It may be added that the Cardinal Octavianus mentioned above was a somewhat obscure prelate, who received the purple from Gregory XII in 1408.

205. The latest editors of Vasari (Opere, ed. Milanesi, I, 184) think this may be a picture in the Museum at Naples, ascribed there to an apocryphal artist ‘Colantonio del Fiore.’ Von Wurzbach says it is by a Neapolitan painter influenced by the Flemings.

206. Roger van der Weyden, more properly called, as by Guicciardini and by Vasari in 1568, ‘Roger of Brussels.’ In 1449 he made a journey to Italy, and stayed for a time at Ferrara, which under the rule of the art-loving Este was very hospitable to foreign craftsmen. He was in Rome in 1450 and may have visited Florence and other centres. His own style in works subsequent to this journey shows little of Italian influence.

207. Hans Memling. ‘No Flemish painter of note,’ remark Crowe and Cavalcaselle, Early Flemish Painters, p. 256, ‘produced pictures more attractive to the Italians than Memling.’ The Portinari, for whom Memling worked, were Florentine merchants who had a house at Bruges, the commercial connection of which with Tuscany was very close. In his Notes on Flemish Painters at the end of the Lives, Vasari says that the subject of ‘a small picture in the possession of the Duke’ which is probably the one here mentioned, was ‘The Passion of Christ.’ If this be the case, it cannot be the beautiful little Memling now in the Uffizi, No. 703, for the subject of this is ‘The Virgin and Child.’ It might possibly however be the panel of ‘The Seven Griefs,’ a Passion picture in the Museum at Turin. On the other hand, Passavant thought the Turin panel was the ‘Careggi’ picture that Vasari goes on to mention. See Note on p. 268 of Crowe and Cavalcaselle’s work.

208. The German editors of Vasari identified Lodovico da Luano with the well-known painter Dierich Bouts of Louvain, but the name Ludovico (Chlodwig, ‘Warrior of Renown’) is not the same etymologically as Dierich (Theodoric, ‘Prince of the People’). It is to be noted that in Guicciardini we find a mention of ‘Dirich da Louano,’ who is undoubtedly Dierich Bouts (the surname is derived from St. Rombout the patron of Haarlem, where the painter, who is also called ‘Dirick van Haarlem’ [see below], was born) and also a mention of Vasari’s ‘Ludovico da Luvano.’ A scrutiny however of the sentence in Guicciardini, where the last-mentioned name occurs, shows that it is copied almost verbatim from our text of Vasari. (Vasari [1550]:—‘Similmente Lodovico da Luano & Pietro Christa, & maestro Martino, & ancora Giusto da Guanto, che fece la tavola della comunione de’l Duca d’ Vrbino, & altre pitture; & Vgo d’ Anuersa, che fe la tauola di Sancta Maria Nuoua di Fiorenza’; Guicciardini:—‘Seguirono a mano a mano Lodouico da Louano, Pietro Crista, Martino d’ Holanda, & Giusto da Guanto, che fece quella nobil’ pittura della comunione al Duca d’ Vrbino, & dietro a lui venne Vgo d’ Anuersa, che fece la bellissima tauola, che si vede a Firenze in santa Maria nuoua’). Vasari is accordingly responsible for this ‘Ludovico da Luano,’ whose name is duly chronicled in von Wurzbach’s ‘Niederländisches Künstler-Lexicon, Leipzig, 1906, II, p. 69, on the authority of Guicciardini alone, and who is called in M. Ruelens’s annotations to the French edition of Crowe and Cavalcaselle ‘Louys de Louvain (peintre encore inconnu).’ Subsequently Guicciardini mentions also a ‘Dirich d’ Harlem,’ who can be none other than the same Dierick Bouts, and Vasari, as a return favour, copies back all three Diericks into his Notes at the end of the edition of 1568. The first ‘Ludovico’ may be merely due to a mistake in the text of Vasari carelessly adopted by Guicciardini. Vasari’s copyist may have written ‘Ludovico’ in place of the somewhat similar ‘Teodorico.’ There was however a certain Ludovicus Dalmau or Dalman (D’Alamagna?), a Flemish painter who worked at Barcelona in Spain about 1445 (von Wurzbach, sub voce) who may be meant, though there is no indication of a connection between him and Louvain.

209. Pietro Crista is of course Petrus Christus or Christi of Bruges, an imitator, though as Mr Weale has shown not an actual pupil, of the van Eycks. Von Wurzbach says that Guicciardini was the first to mention his name, but Vasari in 1550 already knows him. As an explanation of the surname it has been suggested that the artist’s father may have had a reputation as a painter or carver of Christ-figures, so that Petrus would be called ‘son of the Christ-man.’

210. The name Martin belongs to painters of two generations in Ghent, and von Wurzbach thinks it is the earlier of these, Jan Martins, apparently a scholar of the van Eycks, who is referred to here, and called by Guicciardini (see above), and by Vasari in 1568, ‘Martino d’ Holanda.’ There was a later and better known Martin of Ghent called ‘Nabor Martin.’ The more famous ‘Martins,’ ‘of Heemskerk,’ and ‘Schongauer,’ when referred to by Vasari, have more distinct indications of their identity. See, e.g., Opere, V, 396.

211. Justus of Ghent worked at Urbino, where he finished the altar piece referred to by Vasari in 1474. The ‘other pictures’ may be a series of panels painted for the library at Urbino, on which Crowe and Cavalcaselle have an interesting paragraph, op. cit. p. 180.

212. Hugo of Antwerp is Hugo van der Goes, whose altar piece painted for S. Maria Nuova at Florence has now been placed in the Uffizi.

213. Vasari’s stories about the connection with oil painting of Antonello da Messina, Domenico Veneziano, and Andrea dal Castagno have of course been subjected to a good deal of hostile criticism. Those about the two latter artists are in the meantime relegated to the limbo of fable, but the case of Antonello da Messina is somewhat different, and we are not dependent in his case on Vasari alone. He certainly did not visit Flanders in the lifetime of Jan van Eyck, for this artist died before Antonello was born, but von Wurzbach accepts as authentic a visit on his part to Flanders between 1465 and 1475, and sees evidence of what he learned there in his extant works (Niederländisches Künstler-Lexicon, sub voce, ‘Antonello’).

214. ‘Terre da campane,’ ‘bell earths.’ There seem to be two possible meanings for the phrase. It may refer to the material used for the moulds in bell casting, or to the clay from which are made the little terra-cotta bells by which children in Italy set great store on the occasion of the mid-summer festival. This last is improbable.

Baldinucci, Vocabolario del Disegno, sub voce ‘Nero di Terra di Campana,’ says that this is a colour made out of a certain scale that forms on moulds for casting bells or cannon, and that it is good with oil, but does not stand in fresco. Lomazzo also mentions the pigment.

215. ‘L’abbozza’ evidently refers to the first or underpainting, not to the sketch in chalk, for in the first edition the passage has some additional words which make this clear. They run as follows: ‘desegnando quella: e così ne primi colori l’abozza, il che alcuni chiamono imporre.’

216. With the above may be compared ch. 9 of Book VII of L. B. Alberti’s De Re Aedificatoria.

217. 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.

218. The use of canvas for the purpose in view was, as Vasari mentions below, very common at Venice, where as early as about 1476, if we believe Vasari (Opere, III, 156), Gentile Bellini executed in this technique the large scenic pictures with which he adorned the Hall of Grand Council in the Ducal Palace. Such a process would come naturally enough to Italian painters as well as to the Flemings, for they had been accustomed from time immemorial to paint for temporary purposes on banners and draperies, after a fashion of which Mantegna’s decorative frieze on fine canvas at Hampton Court is a classic example. Canvas had however been actually used for pictures even in ancient Egypt. Not only was the practice of stretching linen over wooden panels to receive the painting ground in use there in the time of the New Empire, but some of the recently discovered mummy-case portraits from Egypt, of the earliest Christian centuries, are actually on canvas. There is an example in the National Gallery. At Rome painting on canvas is mentioned by Pliny (Hist. Nat., XXXV, 51) and Boethius (de Arithmetica, Praef., I) says that ‘picturae ... lintea operosis elaborata textrinis ... materiam praestant.’ The Netherland painters of the fifteenth century nearly always painted on panel, but canvas was sometimes used, as by Roger van der Weyden in his paintings for the Town Hall at Brussels.

219. Vasari prescribes ‘due o tre macinate’ of white lead for mixture with the flour and nut oil for the priming of canvas. A ‘macinata’ was the amount placed at one time on the ‘macina’ or stone for grinding colours. Berger suggests ‘handfuls’ as a translation, but the amount would be small, as for careful grinding only one or two lumps of the pigment would be dealt with at one time.

220. The Ducal Palace, that adjoins S. Marco, is probably the building in Vasari’s mind. The Library of S. Marco, Sansovino’s masterpiece, might also be meant, as this was called sometimes the Palace of S. Marco. We must remember however that, as noticed before, ante, p. 56, this building, at the time of Vasari’s visit to Venice, was still unfinished.

221. On panels and canvases as used at Venice Vasari has an interesting note at the beginning of his Life of Jacopo Bellini (Opere, III, 152). This was a subject that would at once appeal to his practical mind when he visited the city. He notices incidentally that the usual woods for panels were ‘oppio’ acer campestris, maple; or ‘gattice,’ the populus alba of Horace, but that the Venetians used only fir from the Alps. (Cennini, c. 113, recommends poplar or lime or willow. Pliny, Hist. Nat., XVI, 187, speaks of larch and box, and Ilg says that northern painters generally used oak.) The Venetian preference for canvas, Vasari says, was due to the facts that it did not split nor harbour worms, was portable, and could be obtained of the size desired; this last he notes too in our text. Berger (Beiträge, IV, 29), gives the meaning of ‘Grossartigkeit’ to the word ‘grandezza’ used above by Vasari, but of course it only means material size, not ‘grandeur’ in an aesthetic sense.

222. See ‘Introduction’ to Architecture, § 13, ante, p. 54. The stone is a species of slate. Slate is suitable for painting on. See Church’s Chemistry of Paints and Painting, 1890, p. 21.

223. Greek paintings on marble panels have come down to us from various periods of ancient art. Some early Attic specimens on tombstones are in the museums of Athens, and at Herculaneum there was found an interesting painting on marble of a group of Greek heroines playing at knuckle bones. A much earlier slab with a figure of a warrior is in the Acropolis Museum at Athens.

224. These chiaroscuri or monochromes are characteristic of the later Renaissance. They may either be frankly decorative, and in this form obey the rules of all other pictorial enrichment; or they may have an illusive intention, and be designed to produce the appearance on a flat wall of architectural members or sculptured or cast-bronze reliefs. In this case, when on monumental buildings and permanent, they are insincere and opposed to sound decorative principles, though on temporary structures they are quite in place. Vasari was a famous adept at the construction and adornment of such fabrics, which were in great demand for the numerous Florentine pageants and processions. See his letters, passim.

225. There are examples of painted imitations of bronze in Michelangelo’s frescoes on the vault of the Sistine. The medallions held by the pairs of decorative figures of youths on the cornice are painted to represent reliefs in this metal. Raphael’s Stanze and Loggie also furnish instances, and there are good examples on the external façade of the Palazzo Ricci at Rome.

226. The clay or earth that Vasari speaks of forms the body of the ‘distemper’ or ‘gouache,’ as it would be called respectively in Britain and in France, and takes the place of the ‘whitening’ used in modern times. Baldinucci in his Vocabolario explains ‘Terra di cava o Terretta’ as ‘the earth (clay) with which vessels for the table are made, that mixed with pounded charcoal is used by painters for backgrounds and monochromes, and also for primings, and with a tempera of size for the canvases with which are painted triumphal arches, perspectives, and the like.’ It is of very fine and even texture, and Baldinucci says it was found near St. Peter’s at Rome, and also in great quantity at Monte Spertoli, thirteen miles from Florence.

227. This process of wetting the back of the canvas is to be noted. The chief inconvenience of the kind of work here spoken of is that it dries very quickly, and dries moreover very much lighter than when the work is wet. Hence it is an advantage to keep the ground wet as long as possible till the tints are properly fused, so that all may dry together. Wetting the back of the canvas secures this end. The technique that Vasari is describing is the same as that of the modern theatrical scene-painter, and would be called ‘distemper painting.’ The colours are mixed with whitening, or finely-ground chalk, and tempered with size. The whitening makes them opaque and gives them ‘body,’ but is also the cause of their drying light. F. Lloyds, in his Practical Guide to Scene Painting and Painting in Distemper, Lond. 1879, says (p. 42) ‘In the study of the art of distemper painting, a source of considerable embarrassment to the inexperienced eye is that the colours when wet present such a different appearance from what they do when dry.’

228. Does Vasari mean by ‘tempera’ yolk of egg? It has this sense with him sometimes, as in the heading of chapter VI.

229. Cennini in his 67th chapter gives directions for preparing the mixed colour he calls verdaccio. It was a compound of white, dark ochre, black and red.

230. The principle of sgraffito-work, that is the scratching through a thin superimposed coat to bring to view an under layer of a different colour, seems to have been established first in pottery making, and in this connection the Italians called it ‘Sgraffiato.’ The adoption of the process for the decoration of surfaces of plaster or cement was an innovation of the Renaissance, and Vasari appears to have been the first writer who gives a recipe for it. According to his account in the Lives, it was a friend of Morto da Feltro, the Florentine Andrea di Cosimo, who first started the work, and Vasari describes the process he employed in phrases that correspond with the wording of the present chapter (Opere, ed. Milanesi, V, 207). A modern expert describes the process as follows: ‘A wall is covered with a layer of tinted plaster, and on this is superimposed a thin coating of white plaster. The outer coat is scratched through, and the colour behind it is revealed. Then all the white surface outside the design is cut away, and a cameo-like effect given to the design. This is the art of Sgraffito as known to the Italian Renaissance’ (Transactions, R.I.B.A., 1889, p. 125). The process dropped out of use after a while, but was revived in Germany in the middle of the nineteenth century, mainly through the agency of the architect Gottfried Semper, the author of Der Stil. It is sometimes used in our own country both on monumental and on domestic buildings, and as it is simple and cheap and permanent it is well fitted for modern use in our climate. The back of the Science School in Exhibition Road, S. Kensington, was covered with sgraffiti by the pupils of the late F. W. Moody about 1872. They would be the better now for a cleansing with the modern steam-blast.

231. See the Notes on ‘Enriched Façades,’ and ‘Stucco “Grotesques,”’ at the close of the ‘Introduction’ to Painting, postea, pp. 298, 299.

232. This passage presents some difficulty. It runs ‘Dunque, quelle che vanno in campo bianco, non ci essendo il campo di stucco per non essere bianca la calce, si dà per tutto sottilmente il campo di bianco.’ Vasari seems to have in his mind the difference between ordinary plaster made, as he has just described, of ‘lime mixed with sand in the ordinary fashion,’ which would not be white, and what he calls ‘stucco,’ by which term is probably meant the finer plaster made of white lime from travertine and marble dust. Ordinary plaster has accordingly to be coated with white before the work begins.

233. Examples of this whimsical style of decoration are abundant in the Pompeian wall paintings, and the mind of Vitruvius was much exercised about their frivolity and want of meaning (De Architectura, VII, v).

234. Vasari is not very clear in his account of these methods of work, but it is enough to know that both by the ancients, and at the time of the Renaissance, colour was used largely in connection with these reliefs, and the combination could of course take several forms. In the loggia of the Villa Farnesina, where Raphael worked with his assistants, there are painted panels in fresco framed in mouldings of stucco, modelled plaster figures in white against a coloured ground, coloured stuccoes against coloured fields, and tinted bands separating the framed plaster medallions. The same kind of work is found in the Loggie of the Vatican, the Doria Palace at Genoa, and other localities innumerable. Plate XII shows a characteristic section of the decoration of the Vatican Loggie.

235. As in the work described at the close of ch. XII (the beginning of the present section).

236. The word ‘bolus’ is derived from the Greek βῶλος, a lump or clod, and means, according to Murray’s Dictionary, a pill, or a small rounded mass of any substance, and also a kind of reddish clay or earth, used medically for its astringent properties, that was brought from Armenia, and called by the pharmacologist ‘bole armeniac.’ Its use in the arts is due to its unctuous character, which made gold adhere to it. See below. In mediaeval illuminations a ‘bolus’ or small lump of a properly prepared gesso is generally laid on the parchment where gold is to come, so that the raised surface may give the polished metal more effect. The gold over the bolus was always burnished. It may be noticed that our word ‘size’ is really ‘assise,’ the bed or layer under gilding, for which a gluey substance was suitable.

237. A ‘mordant’ as the word implies is some corrosive liquid, such as is used by dyers to bite into the fabric and carry in with it the colouring matter. The word is also employed, as in this passage, for a glutinous size used as ground for gilding, such as the modern decorator’s ‘gold-size.’ Gold laid in this way has a ‘mat’ surface.

238. The scudo was worth in Tuscany about four-and-sixpence of our money. In Florence its value was a little greater.

239. See Note 1, ante, p. 248.

240. For the various processes of preparing a panel for painting and for gilding reference must be made to Cennini’s Trattato, where many technical matters are elucidated that Vasari passes over almost without notice. It must be remembered that Cennini writes as a tempera painter, while in Vasari’s time these elaborate processes were falling out of use. In his chapters 115–119, Cennini gives recipes for what he calls ‘gesso grosso’ and ‘gesso sottile.’ They are made of the same materials, ‘volterrano,’ or plaster from Volterra, which is a sulphate of lime corresponding to our ‘plaster of Paris,’ and size made from parchment shreds; but the plaster for ‘gesso sottile’ is more finely prepared. The plaster, produced by calcining gypsum, is first thoroughly slaked by being drenched with water till it loses all tendency to ‘set,’ and is then as a powder or paste mixed with the heated size. The size makes the composition dry quite hard, and Cennini speaks of its having a surface like ivory.

241. See Note 2, ante, p. 248.

242. This we should call ‘shell gold.’ It is in common use. The employment of the shell represents a very ancient tradition, for shells were the usual receptacles for pigments in late classical and Early Christian times.

243. This is excellent advice. The architectural character of mosaic decoration, the distance of the work from the eye, the nature of the technique and material, all invite to a broad and simple treatment, such as we find in the best mosaics at Ravenna and Rome. Modern work is often too elaborate and too minute in detail.

244. A modern would say that if the work be really inlaid, it should look like inlaid work, and not like something else. In the Italy of Vasari’s day however, as we have seen, painting had so thoroughly got the upper hand, that to ape the nobler art would seem a legitimate ambition for the mosaicist.

245. The durability of mosaic depends on the cement in which the cubes are embedded and on the care taken in their setting. The pieces themselves are indestructible but they will sometimes drop out from the wall. Hence extensive restorations have been carried out on the Early Christian mosaics at Ravenna and other places.

246. In his Proemio delle Vite (Opere, I, 242) Vasari explains what he means by the words ‘antique’ and ‘old.’ The former refers to the so-called ‘classical’ epoch before Constantine; the latter to the Early Christian and early mediaeval period, prior to the Italian revival of the thirteenth century.

247. At S. Costanza (see Note 5, ante, p. 27) on the vault of the aisle there are decorative mosaics of the time of Constantine showing vine scrolls issuing out of vases, and classical genii gathering the grapes. Birds are introduced among the tendrils.

248. The mosaics at Ravenna and S. Marco, Venice, are well known. In the Duomo at Pisa, in the apse, there still remains the Saviour in Glory between the Madonna and John the Baptist, designed by a certain Cimabue, and the only existing work which modern criticism would accept as from the hand of the traditional father of Florentine painting. It may however have been another painter nicknamed ‘Cimabue,’ who worked at Pisa early in the fourteenth century. The mosaics of the Tribune of the Baptistry at Florence were executed in 1225 by Jacobus, a monk of the Franciscan Order, and this fact is attested by an inscription in mosaic which forms part of the work.

249. This mosaic, called the ‘Navicella,’ represents the Gospel ship manned by Christ and the disciples, with Peter struggling in the waves. It has been so much restored that little if any of Giotto’s work remains in it. It was replaced in the seventeenth century, after some wanderings, in the porch of the present Basilica, but Vasari saw it of course in the porch of the old, or Constantinian, church, the entrance end of which was still standing in his day.

250. This mosaic was executed at the end of the fifteenth century by Domenico Ghirlandajo and his brother over the northern door of the nave of the cathedral of Florence. It is still in situ but has been greatly restored. The date 1490 is introduced in the composition.

251. This corresponds with modern practice. The following is from a paper by Mr James C. Powell, who, as practical worker in glass, has been engaged with Sir W. B. Richmond in the decoration in mosaic of the vaults of St Paul’s. ‘The glass which is rendered opaque by the addition of oxide of tin, is coloured as required by one of the metallic oxides; this is melted in crucibles placed in the furnace, and when sufficiently fused is ladled out in small quantities on to a metal table, and pressed into circular cakes about eight inches in diameter and from three-eighths to half an inch in thickness; these are then cooled gradually in a kiln, and when cold are ready for cracking up into tesserae, which can be further subdivided as the mosaicist requires. It is the fractured surface that is used in mosaic generally, as that has a pleasanter surface and a greater richness of colour; the thickness of the cake, therefore, regulates the limit of the size of the tesserae, and the fractured surface gives that roughness of texture which is so valuable from an artistic point of view.’ (Transactions, R.I.B.A., 1893–4, p. 249).

252. This is a point attended to by the best modern workers in mosaic. Where gold backgrounds are used it is advisable to carry the gold into the figures by using it as Vasari suggests for the lights on the draperies. If this were not done the figures would be liable to tell as dull masses against the more brilliant ground. The use of gold backgrounds is specially Byzantine. The earlier mosaics at Rome and at Ravenna have backgrounds of blue generally of a dark shade, which is particularly fine at Ss. Cosma e Damiano at Rome and in the tomb of Galla Placidia at Ravenna. The mosaics at S. Sophia at Constantinople of the sixth century had gold backgrounds, and this is the case also with all the later examples in Italy from the ninth and tenth centuries onwards. The finest displays of these varied fields of gold, now deep now lustrous of hue, are to be seen in S. Sophia, S. Marco at Venice, and the Cappella Palatina at Palermo.

Vasari’s account of the fabrication of the gilded tesserae required for this part of the work is quite clear and agrees with modern practice. The gold leaf is hermetically sealed between two sheets of glass by the fusion of a thin film over it. The technique of the ‘fondi d’ oro,’ or glass vessels adorned with designs in gold, found in the Roman catacombs, was of the same nature.

253. It has been noticed at some places, as at Torcello, that before the cubes were laid in the soft cement the whole design was washed in in colour on the surface of the cement. This facilitated correct setting and avoided any appearance of white cement squeezed up in the interstices between the cubes. On this particular feature of the mosaic technique Berger has founded an ingenious theory of the origin of painting in fresco. It is his thesis, in his Beiträge zur Entwicklungs-Geschichte der Maltechnik, I, München, 1904, that the ancients did not employ the fresco process, but that this was evolved in early mediaeval days out of the mosaic technique as seen, e.g., at Torcello. The stucco, that Vasari describes, must be put on portion by portion, for it only keeps soft two or three days, and can only be used for setting the cubes while in a moist state. Now, Berger contends, if the design for the mosaic be painted in colours on the wet stucco, and the whole allowed to dry, without any use of the mosaic cubes, we should have a painting in fresco, and he imagines that fresco painting began in this way. Unfortunately for the theory, (1), the testimony of Vitruvius and Pliny is absolutely decisive in favour of the knowledge in antiquity of the fresco technique, and, (2), the use of the coloured painting on the stucco as a guide for the setting of the cubes was not normal, and can never have been used so freely as to give rise to a new technique of painting. As a fact, this colouring of the stucco is objected to by the best modern workers on aesthetic grounds, for they point out that the lines of grey cement between the coloured cubes answer to the lead lines in the stained glass window, and should be reckoned with by the designer as part of his artistic effect. No doubt the older mosaicists, like the workers in stained glass, instinctively apprehended this, and had no desire for the coloured cement.