Vasari on technique

by Giorgio Vasari

NOTES ON ‘INTRODUCTION’ TO PAINTING

FRESCO PAINTING.

[§ 81, The Fresco Process, ante, p. [221].]

The fresco process is generally regarded as one of several methods for the production of pictures. It is better to consider it in the first place as a colour finish to plaster work. What it produces is a coloured surface of a certain quality of texture and a high degree of permanence, and it is a secondary matter that this coloured surface may be so diversified as to become a picture.

The history of the process is involved in obscurity, and it is not known who first observed the fact that colours mixed only with water when laid on a wet surface of lime plaster dried with the plaster and remained permanently attached to it. The technique was however known to the Romans, and we obtain the best idea of its essential character from the notice of it by Vitruvius in the third chapter of his seventh book. It is there treated in intimate connection with plaster work, as only the last stage in the technical treatment of a wall. The wall is constructed of stone or brick; it is then plastered; and the plaster is, or can be, finally finished with a wash of colour. Of the character of this antique plaster work something has already been said in a note to § 72, in connection with Sculpture (ante, p. [171]). It could be finished either in a plain face of exquisite surface that might even be polished, or with stamped ornaments in relief or figures modelled by hand; but it could also be completed with colour in the form either of a plain tint or a picture, and this colour would be applied by the fresco process.

Painting ‘a fresco’ means painting on the freshly laid and still wet final coat of plaster. The pigments are mixed with nothing but pure water, and the palette of the artist is limited by the fact that practically speaking only the earth colours, such as the ochres, can be used with safety; even the white has to be made from lime—the Italians called it ‘bianco San Giovanni’—as lead white, called ‘biacca,’ is inadmissible. Vegetable and metallic pigments are as a rule excluded from use. The reason why pigments mixed with water only, without any gum or similar binding material, adhere when dry to the plaster is a chemical one. The explanation of it was given by Otto Dönner in an Appendix to Helbig’s Campanische Wandgemälde, Leipzig, 1868, and is to be found also in Professor Church’s Chemistry of Paints and Painting. When limestone is burnt into lime all the carbonic acid is driven out of it. The result of the slaking of the lime by water, which is preliminary to its use in plastering, is that the material becomes saturated with an aqueous solution of hydrate of lime. This hydrate of lime rises to the surface of the plaster, and when the pigment is laid on, to use Professor Church’s phrasing, it ‘diffuses into the paint, soaks it through and through, and gradually takes up carbonic acid from the air, thus producing carbonate of lime, which acts as the binding material.’ To put the matter in simpler language, lime when burnt loses its carbonic acid, but gradually recovers it from the air, and incidentally this carbonic acid, as it is re-absorbed, serves to fix the colours used in the fresco process. It is a mistake to speak of the pigment ‘sinking into the wet plaster.’ It remains on the surface, but it is fixed there in a sort of crystalline skin of carbonate of lime which has formed on the surface of the plaster. This crystalline skin gives a certain metallic lustre to the surface of a fresco painting, and is sufficient to protect the colours from the action of external moisture, though on the other hand there are many causes chemical and physical that may contribute to their decay. If however proper care have been taken throughout, and atmospheric conditions remain favourable, the fresco painting is quite permanent.

The process of painting, it will be easily seen, must be a rapid one, for it must be completed before the plaster has time to dry, which it would do if left for a night. Hence only a certain portion of the work in hand is undertaken on each day and only so much of the final coat of plaster, called by the Italians ‘intonaco,’ is laid by the plasterer as will correspond to the amount the artist expects to cover before nightfall. At the end of the day’s work, the plaster not painted on is cut away round the outline of the work actually finished, and the next morning a fresh patch is laid on and joined up as neatly as possible to that of yesterday. In the making of these joints the ancient plasterer seems to have been more expert than the Italians of the Renaissance, and the seams are often pretty apparent in frescoes of the fifteenth and sixteenth centuries, so that they can be discerned in a good photograph. When they can be followed, they furnish information, which it is often interesting to possess, as to the amount that has been executed in a single day.

To prevent loss of time it is necessary to have a full-sized cartoon in readiness so that the drawing can be at once transferred to the coat of wet plaster as soon as it has been laid. Vasari speaks of these cartoons in § 77, in the second chapter on Painting, ante, p. [213]. The use of the iron stylus for impressing the lines of the drawing on the wet plaster is to be traced in some of the later Italian frescoes. Another process for carrying out the transfer was called ‘pouncing.’ For this the lines of the cartoon were pricked and dabbed with a muslin bag filled with powdered black, so as to show in dotted contours upon the wall.

Vasari is eloquent, both here and in a passage in his ‘Proemio’ to his whole work, on the judgement, skill, and decision necessary to paint successfully in fresco under these conditions and within these limits of time. The ideal of the process was to complete each portion absolutely at the one sitting. When the wall is once dry, any retouching, reinforcement of shadows, and the like, must be done ‘a secco,’ ‘on the dry,’ that is with pigments mixed with size, egg, or some other tempera, which will bind them to the surface. These after-touches lack the quality of texture and permanence of the true fresco (buon fresco). If size or gum have been used, they can be washed off the wall, and having been laid on a dry surface by a kind of hatching process they are harsh and ‘liney.’ It is often possible in good large-scale photographs to distinguish between the broad soft touches of the frescoist laid on while the ground was wet, and the hard dry hatchings of the subsequent retouching.

The illustration, Plate XV, has been chosen as a good example of the fresco technique. It shows the head of Mary from Luini’s fresco of the ‘Marriage of the Virgin’ at Saronno. The painting is executed in a broad and facile manner, the tints and tones which give the colour and the modelling being deftly fused while the whole is wet, and the darker details, such as the locks of the hair, are struck over the moist ground so that the touches seem soft and have no appearance of hatching. The light-coloured leaves of the garland round the head show the same softness, and they are laid in with a full brush in thick pigment. On the other hand there are marks of retouching where the shadows round the eyes, the corner of the mouth, etc., have been reinforced ‘a secco,’ perhaps by a restorer. These show as thin, hard, wiry lines, and have quite a different appearance from the work on the wet plaster.

It was only in the palmy days of Italian painting, from the latter part of the fifteenth century onwards, that artists were able to dispense almost entirely with retouching. In the earlier period of Giotto and his successors much more was left to be done ‘a secco,’ but the Giottesques fully understood the importance of doing all they could on the wet plaster, and Cennini in the 67th chapter of his Trattato insists that ‘to paint on the fresh, that is a fixed portion on each day, is the best and most permanent way of laying on the colour, and the pleasantest method of painting.’ The truth is that the technique of ‘buon fresco,’ while apparently understood by the Romans, was lost in the west during the early middle ages, though it may have been maintained in the Byzantine cloisters. In the course of the progressive improvements in the art of painting in the fourteenth and fifteenth centuries the old technique was gradually recovered. Recently Ernst Berger, in his Beiträge zur Entwicklungs-Geschichte der Maltechnik, I and II, München, 2nd ed., 1904, has denied that the Romans used the fresco technique, and has evolved an ingenious theory of a derivation of fresco painting from the mural work in mosaic which flourished in the Early Christian centuries. See note, ante, p. [255]. Into the question thus raised it is not necessary to enter, because no reader of Vitruvius or Pliny can have the shadow of a doubt that they knew and were referring to the fresco process. The words of Vitruvius (VII, iii) ‘Colores autem, udo tectorio cum diligenter sunt inducti, ideo non remittunt sed sunt perpetuo permanentes, quod calx,’ etc., and those of Pliny (XXXV, 49) ‘udo inlini recusant’ employed of certain colours which are known not to be admissible in fresco are quite conclusive on this point, and it does not advance science to build up elaborate theories on a denial of obvious facts.

Plate XV
HEAD OF MARY, FROM LUINI’S FRESCO OF THE ‘MARRIAGE OF THE VIRGIN’ AT SARONNO
(From a photograph by Giacomo Brogi)

TEMPERA PAINTING.

[§ 82, Painting in Tempera, ante, p. [223].]

In his appreciation of technical processes Vasari, it will be seen, reserves his enthusiasm for fresco painting, but gives oil the advantage over tempera (ante, p. [230]) in that it (1) ‘kindles the colours,’ i.e., gives them greater brilliancy; (2) enables the artist to blend his pigments on the panel or canvas so as to secure a melting, or as the Italians say a ‘sfumato’ or ‘misty’ effect; (3) admits of a force and liveliness in execution which makes the figures seem in relief upon the surface, and finally (4), as he says at the beginning of chapter VII, is a great convenience, ‘una gran comodità all’arte della pittura.’ The only corresponding advantages on the side of tempera, as detailed in § 82, ante, p. [223] f., are the facts that all pigments can be used in it, and that the same media serve for work on grounded or ungrounded panels or on the dry plaster of walls; and that paintings in tempera are very lasting. When Vasari came to write of his own works at the end of the Lives in the second edition, his conscience seems a little to have smitten him, and he gives the process a word of special commendation. He speaks of using it for some mural paintings in his private house which he had just built at Arezzo, and says, ‘I have always reverenced the memory and the works of the ancients, and seeing that this method of colouring “a tempera” has fallen out of use, I conceived the desire of rescuing it from oblivion. Hence I did all this work in tempera, a process that certainly does not merit to be despised or neglected’ (Opere, VII, 686).

If antiquity and wide diffusion be criteria of rank among painting processes, then tempera may claim the first place of all. The Spaniard Pacheco, the father-in-law and teacher of Velasquez, remarks on the veneration due to it because it had its birthday with art itself. As a fact all the wall paintings in ancient Egypt and Babylonia and Mycenaean Greece, all the mummy-cases and papyrus rolls in the first-named country, are executed in tempera, and the same is probably true of all the wall paintings in Italian tombs, as well as of the lost mural work of Polygnotus and his school, and the panel paintings of all the Greek artists save those who, in the later period after Alexander, adopted encaustic. Though fresco was known as a mural process to the Romans it was not used in the Early Christian catacomb paintings, nor in the mediaeval wall paintings north of the Alps, for all these were in tempera. For panel painting, both in the East and the West, save for a doubtful and in any case limited use of oil, tempera was in constant employment till in the fifteenth century it began to be superseded by the new oil media popularized by the van Eycks. Even then tempera maintained its ground, and it is not always realized that artists like Mantegna, Botticelli and Dürer were as a rule in their panel work tempera painters. In the case of mural work at any period fresco can really never have wholly superseded tempera, for fresco can only be worked on fresh plaster, while the artist must often have to decorate walls already plastered and long ago dry. In this case there would be a choice between replastering for fresco and the more economical alternative of employing some form of tempera.

It is however with tempera painting on panels rather than with mural work that we are here concerned. Vasari’s summary treatment of the process in § 82 ante, p. [223], contrasts with Cennini’s far more elaborate directions, and is a measure of the destructive effect of the inroad of oil painting on the more venerable system. At the outset of his Trattato Cennini gives a list of the processes the panel painter has to go through. The preliminary ones, before painting actually begins, will take him six years to learn and Cennini needs about a hundred chapters to describe them. The artificer must know how to grind colours, to use glue, to fasten the linen on the panel, to prime with gesso, to scrape and smooth the gesso, to make reliefs in gesso, to put on bole, to gild, to burnish, to mix temperas, to lay on grounding colours, to transfer by pouncing through pricked lines, to sharpen lines with the stylus, to indent with little patterns, to carve, to colour, to ornament the panel, and finally to varnish it! All this suggests, what was actually the case, that the process of tempera painting was a very precise and methodical one, proceeding by regular stages according to traditional methods and recipes. The result was from the point of view of modern painting something very limited, but within its range, and in the hands of artists of the fifteenth century, it was a very finished and exquisite artistic product, one indeed to which we return with ever-renewed delight after our yearly visits to the Salon or to Burlington House. A certain natural reaction, that some artists of to-day have felt against the slashing impressionistic style, has led to a revival of the old precise technique, which is now cultivated in London in a Society of Painters in Tempera. It should be remembered that it is perfectly possible to paint ‘a tempera’ in a free and loose fashion with a full impasto and individualistic handling. If dry powdered colours be mixed with the yolk or whole inside of an egg without dilution, the resulting pigment is as full of body as oil paint and can be manipulated in the same fashion. What is generally understood however by the tempera style is the painting of the fifteenth century on panel, in which, as Cennini indicates, the egg would be diluted with about its own bulk of water. This rendered the pigment comparatively thin and as a result transparent, and allowed coat to be laid over coat, so that Cennini contemplates seven or eight or even ten coats of colour tempered with egg yolk diluted with water. These are laid over an underpainting in a monochrome of terra verte, and are so transparent that even at the end the ground will remain slightly visible (c. 147) and so help the modelling. It is however a difficulty in tempera that it dries very quickly, too quickly to admit of that fusing of the tints while the impasto is wet, which Vasari mentions as an advantage in the oil process, § 83, ante, p. [230]. Hence the usual ways to model in tempera are (1) to superimpose coats varying in tone, and (2), to use hatching, a process very observable in early Italian temperas, such as some ascribed to Botticelli in the National Gallery. Another drawback, not so marked however in egg tempera as in the size tempera with a basis of whitening used by scenic artists, is that the colours dry lighter than they appear when wet. Those who in the present day are enamoured of the tempera process say that these inconveniences do not trouble them, while they delight in the purity of the tints, the precision of the forms, which it enables them to preserve, and in a certainty and reposefulness which seem to belong to it. One of these writes as the result of her experience ‘In tempera you work with solid paints, and blending must be extremely rapid, or a substitute for this must be found in thin washes or in hatching. Crisp work is again a great beauty, but from the rapid drying of the paint in the brush, and its un-tenacious quality, it is a difficulty. Vasari is right in saying oil is a great convenience, but its introduction does not seem to have been in all respects a gain.’

OIL PAINTING.

[§ 83, Oil Painting, its Discovery and Early History, ante, p. [226].]

The bare fact of the invention of oil painting by John of Bruges, recorded by Vasari in 1550 in chapter VII of his ‘Introduction’ to Painting, is in the Life of Antonello da Messina, in the same edition, retold in the personal anecdotic vein that accords with Vasari’s literary methods. Here the ‘invention’ followed on the splitting of a particular tempera panel, varnished in oil, that according to traditional practice van Eyck had put out in the sun to dry. The said artist then turned his attention to devising some means for avoiding such mischances for the future, and, in Vasari’s words, ‘being not less dissatisfied with the varnish than with the process of tempera painting, he began to devise means for preparing a kind of varnish which should dry in the shade, so as to avoid having to place the pictures in the sun. Having made experiments with many things both pure and in compounds, he at last found that linseed and nut oil, among the many which he had tested, were more drying than all the rest. These therefore, boiled with other mixtures of his, made him the varnish which he had long desired.’ This varnish, Vasari goes on to say, he mixed with the colours and found that it ‘lit up the colours so powerfully that it gave a gloss of itself,’ without any after-coat of varnish.

If we ask What is the truth about this ‘invention’ of van Eyck, or of the brothers van Eyck (see ante, p. [226], note 1), the first answer of any one knowing alike the earlier history of the oil medium and Vasari’s anecdotal predilections would be ‘there was no invention at all.’ The drying properties of linseed and nut oil, and the way to increase these, had been known for hundreds of years, as had also the preparation of an oil varnish with sandarac resin. There is question too of a colourless spirit varnish, and of the process of mixing varnish with oil for a painting medium, in documents prior to the fifteenth century. The technique of oil painting is described by Theophilus, about 1100 A.D.; in the Hermeneia or Mount Athos Handbook; and in the Trattato of Cennini, while numerous accounts and records of the thirteenth and fourteenth centuries establish incontestably, at any rate for the lands north of the Alps, the employment of oils and varnishes for artistic wall and panel painting. The epitaphs for the tombs of the two van Eycks make no mention of such a feat as Vasari ascribes to them, and it is quite open to any one to argue, as is the case with M. Dalbon in his recent Origines de la Peinture à l’Huile, Paris, 1904, that it was no special improvement in technique that brought the van Eycks their fame in connection with oil painting, but rather an artistic improvement that consisted in using a traditional process to execute pictures which in design, finish, beauty, and glow of colour, far surpassed anything previously produced in the northern schools. There is a good deal of force in this view, but at the same time it is impossible to deny to the van Eycks the credit of technical improvements. They had a reputation for this long before the time of Vasari. In 1456, fifteen years after the death of the younger brother Jan, Bartolomeo Facio of Spezia wrote a tract De Viris Illustribus in which he spoke of John van Eyck as specially ‘learned in those arts which contributed to the making of a picture, and on that account credited with the discovery of many things in the properties of colours, which he had learned from ancient traditions recorded by Pliny and other writers.’ The Florentine Filarete, c. 1464, knew of the repute of Jan van Eyck in connection with the oil technique. Hence we may credit the van Eycks with certain technical improvements on traditional practices and preparations in the oil technique, though these can hardly be termed the ‘invention of oil painting,’ while their artistic achievement was great enough to force into prominence whatever in the technical department they had actually accomplished.

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.

It is not a little remarkable that although all the great ancient nations were familiar with this material, it was not till the late Greek and Greco-Roman periods that any general use was made of it as an independent vehicle of artistic effect. The Egyptians coated their walls with plaster of exquisite quality, which they brought to a fine, almost a polished, surface for their tempera paintings. The inhabitants of Mesopotamia protected their mud-brick walls with thin coats of lime plaster, sometimes only about a quarter of an inch in thickness but perfect in durability and weather-resisting properties. The Phoenicians at Carthage plastered the interior walls of their tombs, and the expression ‘whited sepulchres’ shows that Jewish tombs were coated in the same fashion. All through the historical period of Greek art plaster was at the command of the architect, to cover, and fill up inequalities in, the rough stone of which so many of the Hellenic temples were built, and fragments of the pre-Persian buildings of the Athenian Acropolis, still preserved on the rock, show how finely finished and how adhesive was this stucco film. So far as we know however none of the peoples just named seem to have modelled in the material, or used it for any of the decorative purposes for which the Greeks at any rate employed so largely the material of burnt clay. The exception is in the case of the older Aegean peoples, for the Cretans of Knossos made, as all the world now knows, a most effective artistic use of modelled stucco. This Aegean work may be connected technically with Egypt, for in the latest Egyptian period a considerable use was made of modelled plaster for sepulchral purposes, in the form of mummy-cases in which the features of the deceased, with headdress, jewels, etc., were represented in this material. The technique may go back in Egypt to the remoter times and may have been carried thence to the Aegean lands. The process however was apparently not inherited by the historical Greeks, who did not begin to use plaster freely and artistically till the later Hellenistic or Greco-Roman period.

Some late Greek private houses of the second or first century B.C., on Delos, show a beginning of modelled plaster work in the form of drafted ashlar stones imitated in the material, and it may be conjectured that the technique was developed at Alexandria, for the earliest existing mature works in the style, the famous stucco reliefs and mouldings found near the Villa Farnesina at Rome, resemble in many respects the so-called ‘Hellenistic’ reliefs, with landscape motives, that are ascribed to the school of Alexandria. In these stuccoes, now preserved in the Terme Museum at Rome, there are bands of enrichment stamped with wooden moulds, after the fashion described by Vasari in the ‘Introduction’ to Sculpture, § 73, that enclose fields wherein figure compositions with landscape adjuncts, or single figures, have been modelled by hand. Many of these last are of great beauty of form, and the whole have been executed with the lightest but firmest touch and the most delightful freedom. Some ceiling decorations in two tombs on the Via Latina, of the second century A.D., are almost as good in execution, and are interesting as giving in typical form ancient models that have been much copied at the Renaissance and in more modern times.

Early Christian artists, both in the West and in the East kept up the artistic use of stamped or modelled stucco. The Arabs inherited the technique, and at Cairo, and in the East and in Spain, they made a very extensive and tasteful use of the tractable material in their own style of artistic decoration. This style, like that of Byzantium, from which in great part it was derived; and that of the familiar Indian work in the exquisite marble-dust plaster or chunam, is chiefly surface decoration, without much plastic feeling, and relying mainly on geometrical, or at any rate inorganic, motives and forms. Bold modelling of forms accentuated by light and shade, as we are kindly informed by Dr James Burgess, does occur in old Buddhist work in northern India, and some excellent examples have recently been published in Ancient Khotan (Chinese Turkistan) Oxford, 1907, vol. I, p. 587 and pl. liii ff. The work however belongs essentially to the West rather than to the East, and the middle ages in Western Europe produced some remarkable works in this style. There is some modelled stuccowork of early date in the Baptistry at Ravenna, but the most interesting examples of the period in Italy are the large figures of saints and the archivolt enriched with very bold and effective vine scrolls, that are to be seen in the interior of the little oratory of S. Maria in Valle (or Peltrude’s chapel) at Cividale in Friuli. These very remarkable works, with which may be connected the stuccoes of the altar ciborium at S. Ambrogio, Milan, date about 1100, and may be paralleled by similar figures, equally plastic in treatment, and of about the same period, north of the Alps, in St. Michael’s at Hildesheim. Signor Cattaneo calls the Cividale work ‘Byzantine,’ but life-sized plastically-treated figures in high relief represent a form of decorative art that was not practised at Byzantium, and the work, like a good deal else that is too lightly dubbed ‘Byzantine,’ is no doubt of western origin, and is a proof that the tradition of modelling in plaster was handed down without a break through the mediaeval period.

At the Renaissance the tradition was revived, and this style of decoration was developed in Tuscany and North Italy, while one of its most conspicuous triumphs was the adornment by Italian artists in the first half of the sixteenth century of the Galerie François Premier and Escalier du Roi at Fontainebleau in France. It spread also to our own country, where artists of the Italian school carried out work in the same thoroughly plastic style in the now destroyed palace of Nonsuch, under the patronage of Henry VIII.

This is not however the style that Vasari has in view when he speaks of ‘stucco grotesques.’ What he means is an imitation of ancient stamped and modelled plaster decoration, of the type of that represented in the tombs on the Via Latina just referred to. Here the scale is small, though the work may cover large spaces, and the design is on the whole of a light and fanciful kind. The impulse to it dates from the early years of the sixteenth century when considerable discoveries were made at Rome, in the Baths of Titus and elsewhere, of antique apartments or sepulchral chambers decorated in this fashion. As these interiors, when discovered, were all underground they were called ‘caves’ or ‘grottoes,’ and for this reason, as Benvenuto Cellini informs us in the 6th chapter of his Autobiography, the decoration characteristic of them was called ‘grotesque.’ The fact that the designs were so commonly of the fantastic or so-called ‘Pompeian’ order has given to the word ‘grotesque’ its modern meaning of bizarre or semi-ludicrous.

According to Vasari, the painter Morto da Feltro (c. 1474–c. 1519) was the first to study these antique decorations. ‘Our first thanks and commendations’ he says (Opere, ed. Milanesi, V, 205 f.) ‘are due to Morto, who was the first to discover and restore the kind of painting called “arabesques” and “grotesques,” seeing that they were for the most part hidden among the subterraneous portions of the ruins of Rome, whence he brought them, devoting all his study to this branch of art.’ He spent many months also, Vasari tells us, at Tivoli among the ruins of Hadrian’s Villa, and made a journey to Pozzuoli near Naples, all on the same quest. Stucco reliefs in this revived antique style were used at the beginning of the sixteenth century by Pinturicchio in the Appartamenti Borgia in the Vatican, and from that time onwards they become exceedingly common.

TARSIA WORK, OR WOOD INLAYS.

[§ 100, Inlays in Wood, ante, p. [262].]

The covering of one kind of material by another, for reasons of a constructive or an aesthetic kind, is so primitive and so universal that Gottfried Semper made it the fundamental principle of decoration in general, and developed this view in his famous ‘Bekleidungstheorie,’ which dominates der Stil. Semper’s philosophy of art was sufficiently profound for him to see that this process is not to be accused of insincerity because the more costly or beautiful material appears only on the outside, while the mass of the structure may be of commoner fabric. The materials in question are as a rule limited in quantity and it would be bad economy to employ them in positions where their beauty would not be seen. To build a thick wall of rare finely-veined and coloured marble in solid blocks would be to behave like degenerate Roman Emperors. Such material is far more suitably treated when it is exposed in thin layers over as large a superficial area as possible. Hence though there is nothing in the world to equal the fine ‘isodomon’ masonry of the earlier Greeks, which is the same throughout, there is much to be said in justification of the late Greek and Roman technique, so largely used in mediaeval Italy, of incrusting a common material with one of finer grain and colour.

In the case of wood inlays, it may be claimed for the craft that it originates in material need and not in any aesthetic considerations. Wood, of which the grain always runs one way, needs sometimes to be overlaid, braced, and prevented from warping by a slip of the same material placed with the grain at right angles to the first, after the fashion seen in our common drawing-boards. The great variety in colours and markings shown by different woods must however at a very early date have led to the employment of inlays and veneers for reasons of artistic effect, and in this craft the old Oriental peoples were proficient. It is worthy of notice that some Greek wood inlays have survived, and may be seen in the Kertch room at the Hermitage in St. Petersburg. The motives of all early inlays are either geometrical patterns or simple conventional ornament, like the olive sprays which are represented in the Greek work just mentioned. In these forms the craft was preserved through the mediaeval period, and though in the West, at any rate north of the Alps, the mediaeval epoch was one in which ornamentation was plastic rather than graphic, that is to say, in carving more often than in inlay, yet in Moorish lands, and in parts of Italy, inlays, both in stone and wood, were freely developed.

The history of Italian tarsia work takes a new start with the beginning of the Renaissance, and it became as Bode has termed it ‘a true child of the art of the Quattrocento’ or fifteenth century. The earliest examples seem to be in geometrical schemes, influenced by the so-called ‘Cosmati’ work, or inlays of small pieces of coloured stones and gilded pastes, so common in Italy from the twelfth to the fourteenth century. The painted borders to the frescoes of Giotto and other pre-Renaissance masters imitate this kind of work and show how familiar it must have been. Next come conventional ornaments in the so-called ‘Italian’ manner, consisting in acanthus scrolls, swags of fruit and flowers, with classical motives such as horns of plenty and candelabra, among which are soon introduced ‘putti’ or Cupids, terminal figures, etc. As the fifteenth century advanced there was developed the curious penchant, noticed ante, p. [264], for introducing perspective delineations of buildings and articles of furniture into the tarsia designs. Vasari in his Life of Filippo Brunelleschi Opere, ed. Milanesi, II, 333 (see also the text ante, p. [262]), distinctly intimates that this was due to the influence of this artist, whose enthusiasm for perspective studies is well known. The only existing works in wood inlay which might claim to be designed or inspired by Brunelleschi are those in the old sacristy of S. Lorenzo at Florence, but these do not display perspectives, and the subjects comprise only ‘putti’ with candelabra, rosettes, and other simple ornaments. The influence of Brunelleschi on the advancement of the study of perspective was however so great, that Vasari’s view of his general responsibility for the perspectives is credible.

With the perspective designs of the latter part of the fifteenth and beginning of the sixteenth century, was developed the elaborate delineation of objects of still-life, as well as more ambitious work in the representation of the human figure, alone or in groups. These inlays were abundantly displayed in wall panelling and on the doors of presses, and more especially on the backs and frames of choir stalls in the churches. It is characteristic of Italian decoration as opposed to that prevailing at an earlier date north of the Alps, to find choir stalls, which in northern churches are made the occasion of the most splendid display of wood carving in the boldest architectural and plastic styles which the world has to show, decorated in Italy for the most part in a pictorial style with flat inlays.

The number of extant examples, both in the case of presses and of choir stalls, is so great that no enumeration is possible, and the reader is referred for a critical account of the chief monuments of the art to the small book by Dr Scherer, Technik und Geschichte der Intarsia, Leipzig, 1891. The artists who fostered the work were also very numerous, and represent many centres in the northern parts of Italy. We learn for instance that in Florence alone in the year 1478 there were no fewer than 84 botteghe where tarsia work was in full practice. The names actually mentioned by Vasari will suffice to represent the chief phases of the craft. If Brunelleschi may have started the idea of perspective designs, these were carried out to great perfection by Fra Giovanni da Verona, whose master-works, the stalls and presses in S. Maria in Organo at Verona, dating from about 1500 onwards, are among the most famous examples of the kind. Here are perspectives of buildings and furniture, objects of still-life, and the like, with geometrical patterns in the framings and on the dado. In figure work Benedetto da Majano, whom Vasari mentions, and more especially his brother Giuliano da Majano, were masters of the very first rank, and the examples left by the latter on the presses of the sacristy of the Duomo at Florence, and on the door leading to the Sala d’ Udienza in the Palazzo Vecchio, are masterpieces of technique and style. At a later date near the middle of the century, the artist mentioned by Vasari towards the end of his chapter XVII, Fra Damiano of Bergamo, a pupil of the same Venetian school from which proceeded Fra Giovanni of Verona, executed at S. Domenico in Bologna a series of works in tarsia that represent the furthest development in a pictorial direction that the craft ever attained.

Plate XVI
EXAMPLE OF TARSIA WORK
S. Zenobi, by Giuliano da Majano, in Opera del Duomo, Florence

Of this display however Dr Scherer aptly writes (p. 80) that, ‘whoever demands from wood an effect similar to that of a picture, sets it in ignorance of its nature to tasks that are beyond its capabilities, and constrains material and technique to exaggerated efforts which are contradictory to their character. This is the fundamental error that clings to all the works of the much-belauded Fra Damiano and is calculated seriously to obscure his greatness.’ The development of tarsia work was in the direction of pictorial effects. Though purely decorative patterns of a geometrical or conventional kind were always used, they tended as the art advanced to be confined to borders and subsidiary parts of a design, while the principal fields were pictorially treated. The introduction of perspectives naturally led to the accentuation of the third dimension of objects, and in still-life compositions modelling and shading were deemed essential. The human figure, the use of which increased greatly as the fifteenth century advanced, was given its plastic roundness which it was assuming in the contemporary frescoes. Conventional leafage, etc., was no longer treated for the effect of a mere flat pattern. In the latter part of the century the figure work of Giuliano da Majano shows how far in this direction the art could be carried while still preserving its sincerity as a mosaic of natural woods. In this work the utmost advantage is taken of the varieties shown by woods in colour and texture, without dependence on artificial colouring matters, and those pictorial refinements over which Vasari sings his usual paean, but which really prefigure the decline of the art. A close examination of a specimen of Giuliano’s inlays of about 1470–80, such as the S. Zenobi now in the Opera del Duomo at Florence (see Plate XVI), shows extraordinary skill and patience in the laborious work. The outlines are marked by thin strips of black wood; the staff which the Saint holds in his hand, though it is not half-an-inch broad, is modelled in light and shade with no fewer than six parallel strips of wood varying in light and dark. The hands are carefully modelled in inlays. The mouth of the figure on the right of the Saint has one piece for the upper lip and a lighter piece for the lower in which the two lights on the lobes are let in with separate pieces. The shadow between the lips and the light on the lower edge of the lower lip are inserted with strips of dark and light tinted wood. In one of the most interesting works of the da Majano brothers, the two portrait figures of Dante and Petrarch, on the door leading into the Sala d’ Udienza in the Palazzo Vecchio at Florence, the face of the older poet is deeply furrowed, and in order to prevent the inlaid streaks appearing too hard and ‘liney’ they are made up of an infinite number of little morsels of wood the size and shape of millet grains, each one glued down into its place. Such work impresses the spectator by its sincerity and earnestness as well as by its technical mastery.

The use of artificial colouring matters, over and above the burning which was the first device employed to give an effect of shading in special places, destroys for us this aspect of sincerity. The material is no longer allowed to express itself in its own character, and taste revolts from the work as it does from tapestry in which pigments have been used to give details for which stitches should in the theory of the work suffice. The case is different from that of the coloured wax medallions noticed ante, p. [188] f., where the scale is so small, and the detailed representation of nature so essential a part of the work, that waxes coloured in the piece could hardly be made to avail.

THE STAINED GLASS WINDOW.

[§ 101, Stained Glass Windows, their Origin and History, ante, p. [265].]

This is not a specially Italian form of the decorative art, but belongs rather to France and north-western Europe. A proof of this may be found in the fact that in 1436 the Florentines have to send for a worker in glass from Lübeck in Germany to make windows for their Duomo (Gaye, Carteggio, II, 441 f.), while at the beginning of the next century Pope Julius II summons French verriers to supply coloured windows for the Vatican (see ante, p. [266], note). The art was differently regarded north and south of the Alps, and Vasari in his account of it gives, in § 102, the tradition of the northern schools, but lets us see at the same time, in § 101, how the Italians were accustomed to envisage the craft.

There is accordingly in his treatment a confusion between two distinct ideals of the art, one traditional and northern, the other congenial to an Italian painter of the sixteenth century. According to the first ideal of the art, that on which it was founded and nurtured north of the Alps, it depended for its effect upon coloured glass, that is upon the varied tints of pieces of glass stained in the mass with metallic oxides, and called by the moderns ‘pot-metal.’ These different coloured pieces were so arranged and so treated as to give the appearance of figures or ornaments, and to this extent the effect was pictorial, but such a window would depend for its beauty far more on the sumptuous display of coloured light than on any delineation of figures or objects.

The sort of window which would present itself to the Italian of the Renaissance, as representing his ideal of the art, is rather a transparent picture painted on glass, in which delineation is the chief part of the effect. This is the view that Vasari has in mind, when, in § 101, he insists on transparency in the glass employed. The old glass worker of Chartres or the Sainte Chapelle would hardly have known what to do with transparent uncoloured glass, for this, save in pearl borders, was not an element with which he worked. Vasari however starts with the idea of clear glass and imagines it coloured in such a way as to produce a transparent picture. There were two methods for this colouring. The only satisfactory one was to paint in transparent enamel colours which were afterwards burnt in on to the glass. This was a process specially developed in the fifteenth and sixteenth centuries in Flanders, whence it was probably introduced into Italy.

The other method was to employ transparent pigments, such as were used for ordinary painting, and to fix them on the glass by means of gum or varnish. This method is of course a mere pis aller to which no self-respecting worker in glass would like to have recourse, and must be regarded as merely a cheap imitation of true glass-painting in enamel colours. That is to say, it did not precede, as Vasari suggests in § 101, but followed as an imitation, the development of true enamel painting. That the two processes were in use in Italy in Vasari’s time is shown by a contract printed by Gaye, Carteggio, II, 446, in which certain windows to be executed at Arezzo in 1478 are to be ‘cotte al fuoco,’ ‘burned in the fire,’ and not merely to have the colours ‘messi a olio,’ ‘laid on in oil paint.’

The earlier glass workers of the palmy days of the craft, from the twelfth to the fourteenth century, in France, England, Flanders, or Germany, aimed at different effects altogether, and their technique is explained by Vasari in § 102, (ante, p. [268]), where the whole character of the work envisaged differs from the painted work previously in contemplation. As is indicated in a footnote to the text, the description of the work, which starts it will be noticed with ‘bits of red, yellow, blue, and white glass,’ not with a clear pane, is almost exactly what we find in Theophilus, though a little less simple, and represents the early tradition of the mediaeval masters. Their work was the development of an Early Christian technique. Coloured glass, which it must be remembered is really easier to procure than glass perfectly clear, was first used in little rounds or squares for insertion in the holes pierced in marble or plaster slabs that filled window openings. Such window fillings are to be seen in mosques and Byzantine churches. The next stage was a mosaic of pieces of coloured glass arranged on a certain scheme and perhaps displaying geometrical patterns. No specimens of early windows of this kind seem to have survived, but they are referred to in contemporary documents, as in the Liber Pontificalis, where it is said that Leo III, 795–816, in Old St. Peter’s, ‘fenestras de apsida ex vitro diversis coloribus conclusit.’ It is not clear whether such mosaics, or something more pictorial, is referred to by Abbot Gozbert of Tegernsee about the year 1000 A.D. as ‘discoloria picturarum vitra,’ but about this same epoch we find it stated of Archbishop Adalberon of Reims, who died in 989 A.D., that he supplied his church with ‘fenestris diversas continentibus historias,’ which certainly implies something more than the kaleidoscope effect of a mere conjunction of coloured pieces. Theophilus, whose treatment of the process shows that it was fully established at the time of his writing, say about 1100 A.D., makes it clear wherein the innovation consisted. The new invention was that of a pigment, of a brown colour when fused, with which could be painted any details or shading required for representing the forms of objects. A mere patch of pale flesh-coloured glass the shape of a face would tell nothing, but when the features, the locks of the hair, and the like, were painted in with this pigment then the patch became a human countenance. In the same way a piece of red or blue glass with some lines and shading on it became a garment, and so on with the representation in a simple and summary fashion of the objects necessary to constitute the sort of pictorial representation suitable to the technique. The coloured glass remained throughout the essential element in the effect. All the finest glass windows of the twelfth and thirteenth centuries were executed with these simple media. The later history of the art shows as usual a progressive advance in the importance of the pictorial element, till by the sixteenth century coloured glass is scarcely needed, and the pictorial effect desired may be gained by fusing pigments on to clear glass, in the way Vasari contemplates in § 101 (ante, p. [267]).

Of this Italian stained glass of the Renaissance period very good examples are to be seen in the Laurentian Library at Florence, and a specimen is shown on Plate XVII.

Plate XVII
PAINTED GLASS WINDOW IN THE LAURENTIAN LIBRARY, FLORENCE

Chapter XIII of Charles Heath Wilson’s Life and Works of Michelangelo contains a good critical notice of the decorative work at the Laurentian Library. The windows, which were not executed till long after the death of Clement VII whose name appears on the glass, he thinks may be mainly from the designs of Vasari’s friend Francesco Salviati, a pupil of the glass painter Guglielmo da Marcillat. He writes of them:—‘These windows both in design and colour are admirably suited to Italian architecture, and offer useful lessons at the present time. Introduced into a Library where plenty of light was indispensable, white glass prevails. There is much yellow (silver) stain, and where colour is wanted in some parts, pot metal is introduced, but there is not much of it. The shadows are vigorously painted in enamel brown of a rich tone. Unlike modern painted glass, the figures and ornaments are drawn with all the skill of an educated artist, and it is a pleasure to look at them.’

The Victoria and Albert Museum in London affords the opportunity for a comparison of all these different styles. There is some original glass of the thirteenth century from the Sainte Chapelle at Paris, made of small pieces of very richly tinted glass, coloured in the mass, the effect being more that of a very rich and beautiful diaper pattern than a picture; while close by may be seen a Flemish window of 1542, in which the pieces of glass are of large size and in many cases are white, the necessary colouring being added in different enamel pigments. The subject is the Last Supper, and a purely pictorial result is aimed at, the effect of colour being as a fact extremely poor.

VASARI’S DESCRIPTION OF ENAMEL WORK.

[§ 105, Enamels over Reliefs, ante, p. [276].]

Coloured vitreous pastes are among the most valuable materials at the command of the decorative artist, and are employed in numerous crafts, as for example for the glazes of keramic products including floor or wall tiles, for painted glass windows, for glass mosaic, and for enamel work. The glass is tinged in the mass with various metallic oxides, one of the finest colours being a ruby red gained from gold. Silver gives yellow, copper a blue-green, cobalt blue, manganese violet, and so on. Tin in any form has the property of making the vitreous paste opaque. The material is generally lustrous, and it admits of a great variety in colours some of which are highly saturated and beautiful. It is on the lustre and colour of the substance, more than on the pictorial designs that can be produced by its aid, that its artistic value depends.

The difference between opaque and transparent coloured glass is the basis of a division that can be made among the crafts which employ the material. If the glass be kept transparent the finest possible effect is obtained from it in the stained glass window where the colours are seen by transmitted light. A similar effect is secured on a minute scale in that form of enamel work called by Labarte ‘emaux à plique à jour,’ or ‘transparent cloisonné enamel,’ in which transparent coloured pastes are fused into small apertures in metal plates. Old examples in this kind are very rare, but modern workers seem to reproduce it without difficulty. On the other hand transparent or more usually opaque vitreous pastes in thin films form many of the so-called ‘glazes’ which give the charm of lustre and colour to so many products of the potter’s art. The most effective use of opaque coloured glass is in wall mosaic, where it is seen by reflected light, and owes its beauty to its lustrousness as well as to the richness and variety of its hues. Between these two crafts of the stained glass window and mosaic comes that of the enameller, who makes use of vitreous pastes both in an opaque and a transparent condition. The identity of the materials in these different uses is shown by the fact that Theophilus, Bk. II, ch. 12, directs the enameller to pound up and melt for his incrustations the very cubes used in old mosaics, or as he puts it ‘in antiquis aedificiis paganorum in musivo opere diversa genera vitri.’ Enamel work consists in fusing these coloured pastes over surfaces that are generally of metal, the different tints being either distinctly separated by divisions, or else running beside each other, or again interpenetrating like the colours in a picture. Hence there are two main divisions of the enameller’s craft, the painted enamel where the colours are fused on to the metal but produce an effect similar to that of a painting executed with the brush, the special advantage of the enamel being its lustre; and the encrusted enamel, where the effect is more like that of mosaic. Vasari would have thoroughly appreciated the painted enamels, known generally as enamels of Limoges, which are complete pictures, but, though Cellini mentions them, they originated north of the Alps and only came into general vogue after Vasari’s time. The incrusted enamels are earlier, and of these he only describes one particular kind that had its home specially in Italy.

The earliest known enamels, whether Western or Byzantine or Oriental in origin, have the different colours separated in compartments divided from each other by ridges of metal which give the lines of the design. These so-called ‘champlevé’ and ‘cloisonné’ enamels there is no need to discuss, but it may be noted that the pastes used in them, though highly lustrous, are opaque, and cover completely the metal over which they are laid. The enamel described by Vasari differs from these earlier enamels in compartments in that the pastes are transparent, so that the ground shows through. The divisions between the colours also are not so marked. In this kind of work transparent vitreous pastes are fused over a metal ground that has been chased in low relief, so that the light and shade of the relief shows through the transparent coloured film. The work is very delicate and on a small scale, and the ground is nearly always gold or silver. A slight sinking is made in a plate of one of these metals where the enamel is to come, and at the bottom of this sinking the subject is carved or chased in very low relief, so low indeed that Cellini compares the height of it to the thickness of two sheets of paper (Dell’ Oreficeria, c. III). The transparent enamels are then fused over the different parts of the design, the contours of the figures or objects being just allowed to show as fine lines of metal between the different colours.

Examples of this work are rare, but the Victoria and Albert Museum and the British Museum have some good specimens. Transparent enamels are used also in other ways, and are sometimes arranged in apertures (see above) so as to show by transmitted light. Labarte’s Histoire des Arts Industriels is still indispensable as an authority on various kinds of enamel work, though there is a whole literature on the theme.