An account of the condition, conservation, materials and techniques
Arthur Lucas and Joyce Plesters
In the first issue of the ‘National Gallery Technical Bulletin’, which appeared in September 1977, the case-histories given in detail were all of pictures which had very recently undergone examination and treatment. In the present issue it was considered that it might be of some general interest to review the case-history of a picture the most recent restoration of which dates from over ten years ago, Titian's ‘Bacchus and Ariadne’ (No.35), indisputably one of the finest and most famous of all the National Gallery's paintings. At the time the matter of whether the picture ought or ought not to be cleaned became something of a ‘cause célèbre’. It may be that with a decade separating both authors and readers from the event, and passions in the meantime having somewhat cooled, it will be easier to present an objective account.
The history, iconography and provenance of Titian's ‘Bacchus and Ariadne’ are given in detail by Cecil Gould in his National Gallery Catalogue, ‘The Sixteenth Century Italian Schools’(note 1), and in a monograph (note 2) published in 1969 on the occasion of the picture being re-exhibited after cleaning and restoration. It suffices here to say that originally it formed one of a series of paintings of Bacchanalian subjects commissioned by Duke Alfonso I d'Este of Ferrara and was finished by Titian in 1523.
Before its most recent conservation treatment, carried out between 1967 and 1969, the ‘Bacchus and Ariadne’ was seen to be considerably darker and more discoloured than the two companion 'Bacchanals' by Titian, the ‘Worship of Venus’ and the ‘Bacchanal of the Andrians’, both in the Prado, Madrid, although they were, and still are, by no means free from old and yellowed varnish. This in itself might have constituted a valid argument in favour of cleaning the ‘Bacchus and Ariadne’, but, as we shall see, was not the decisive factor in electing for cleaning, that being the physical safety and preservation of the picture as a whole. Varnish removal proved to be a necessary preliminary stage in a complete programme of conservation.
The decision which had to be made as to whether or not to treat the picture has to be seen in the context of the mid-1960s. The early sixties had witnessed a renewal of the 'cleaning controversy' which had raged from time to time in connection with the National Gallery ever since the 1840s. A late offshoot of the 1960s controversy was a series of letters written in 1966 (note 3), some addressed to the Director or Keeper of the National Gallery, others published in ‘The Times’, on the subject of possible future cleaning of the picture. Although the major part of the correspondence constituted a plea for cleaning, there was a predictable hard core of objectors. In April 1967 the Trustees of the National Gallery considered a report by the Chief Restorer, Arthur Lucas, on the condition and an outline of his proposals for treatment. It was decided, however, that an international committee should be set up to advise on any proposed treatment before it was put into practice. The committee (note 4) sat between 22 and 24 April 1967. Their report (note 5), dated 24 April, concluded that the condition of the picture urgently required treatment and that that proposed by the Chief Restorer was appropriate and desirable, with cleaning, in the sense of varnish removal, as an integral part. The Chief Restorer began the task in 1967, completing it in 1969.
History of condition and treatment before 1967
The earlier history of the picture is not without relevance to the disorders which compelled its most recent restoration. Titian began the picture in Venice in 1520 or 1522 and finished it at Ferrara early in 1523, the unfinished canvas having been sent by sea from Venice to the port of Ferrara. In 1598 the picture was transferred from Ferarra to Rome. It was not unusual in the past (and in Venice even today is still often essential) to take a canvas painting off its stretcher and roll it up for ease of transport whether on human- or horseback, by waggon or boat. This operation, particularly if the canvas is rolled into a cylinder of small diameter or rolled with the paint layer innermost, can be very injurious to both paint and ground layers. It would be quite likely to cause both vertical cracks and horizontal cleavage in a rather brittle material like gesso (a form of calcium sulphate bound with animal glue, which was in fact identified as the ground of the ‘Bacchus and Ariadne’). The many small losses noted in the paint layers coupled with the disintegrating state of the gesso ground before its recent consolidation are not inconsistent with rolling of the painted canvas combined with rough handling m transit. The third major journey which the picture underwent was to London in 1806 or 1807. It was known that it was restored on arrival in London and was cleaned either then, or before it left Italy, or both. The English artist, Henry Bone, made a sizeable enamel copy of it which was certainly in existence by 1811, when it was remarked on by Joseph Farington in his diary (note 6). The enamel was exhibited alongside the newly-cleaned original in 1969 and it was remarkable, making only a small allowance for difference of painting medium and possible slight alterations during firing of the enamel, how closely the colours of enamel and newly-cleaned picture coincided. Enamel colours are not normally subject to the discolouring effects of light and atmosphere to which easel paintings, particularly when varnished with natural resin varnishes are prone. The close similarity in colours of the newly-cleaned picture in 1969 and Henry Bone's enamel, which he must have completed a little before 1811, also implies that when the enamel copy was made the original had just undergone, in about 1806 or 1807, as complete a removal of discoloured varnish as in its most recent cleaning. Unfortunately, even up to twenty-five years ago, by which time modern less-yellowing (or even non- yellowing) synthetic resin varnishes had become readily available, newly-cleaned paintings had to be revarnished using the same type of natural resin varnish as that just removed, the most common being mastic resin dissolved in turpentine distillate, with or without the addition of a drying oil such as linseed. (Happily, cases of the use of varnishes based on resins like copal or amber dissolved in drying oils by heating are comparatively rare on pictures cleaned within our time, which is fortunate, since with age they may become extremely difficult to remove; their removal in the past by harsh methods may have been responsible for damage to some pictures.)
Although a varnish of natural resin in a volatile solvent, such as mastic in turpentine, when initially applied in a thin coat imparts no perceptible colour to a picture, it may, with age and exposure, begin to show signs of discolouration in as little as twenty years and eventually the cycle of varnishing and cleaning, cleaning and varnishing would begin all over again. By the time the ‘Bacchus and Ariadne’ was bought for the National Gallery in 1826 it is recorded that the varnish had already begun to turn brown. Twenty years later it was cleaned, but only partially, and re- varnished with a mastic varnish containing a proportion of linseed oil.
It is not known when the first lining canvas, i.e. a new canvas stuck to the back of the old for the purpose of reinforcing the latter, was applied. Almost all canvas paintings of any appreciable age or value are found to have been lined at one time or another. By 1894 the existing lining canvas was reported to be in a bad state and a double lining canvas was substituted which in turn was replaced by a single one in 1929, this last mentioned being the canvas removed in the 1967–1969 restoration. Apart from simple mechanical reinforcement of the exceptionally thin and finely-woven original canvas (see p.38 and Fig.7), the main object of these repeated lining and relining operations on the ‘Bacchus and Ariadne’ would have been to try to obtain better cohesion between the various layers of paint, ground and canvas. It is likely that the thin gesso ground on which the picture is now known to have been painted had long ceased to adhere completely either to the canvas or paint. Deterioration of the gesso ground could have been hastened by the action of water, either in leaching out the glue medium of the gesso or by providing suitable conditions for biological attack by micro-organisms. In fact, in a letter to the Select Committee on the National Gallery of 1853, William Buchanan, through whose hands the picture had passed in 1806, states that he was informed 'that water had been freely used in taking away some surface dirt' and expressed the view that it would have penetrated through cracks and fissures in the surface into the absorbent gesso ground, eventually causing 'the body of the paint itself [. . .] to scale off' (note 7). It is not, however, clear from the context exactly when he believed this cleaning with water to have taken place.
The National Gallery is singularly fortunate in having records of condition and restoration going back to the beginnings of the collection. For much of the earlier data we have to thank Sir Charles Eastlake, the first Director of the National Gallery, who meticulously recorded condition and treatments of pictures as they were acquired in his Manuscript Catalogue, the first volume of which he began in 1856. His example encouraged his successors to keep up similar technical records.
In the case of the Titian ‘Bacchus and Ariadne’ some relevant documentary evidence survives even from before the painting's acquisition. It might be of interest to give a summary of the picture's history of restoration, from documentary and published sources, up to the examination and treatment of 1967–1969:
Irvine wrote to Buchanan from Rome that Day, who had recently bought the picture from the Aldobrandini Palace, intended to have it cleaned (note 8).
Farington records remarks by Benjamin West, PRA: 'He said the picture was really in a fine preservation, but it was mortifying to see that Burch, the picture dealer, had been putting colour upon it, in many parts – upon the sky with ultramarine – and had stippled colour upon parts of the flesh. He said if the picture was his he would take off the whole of what Burch had done, for he knew he was the person that had done it in order to make the picture appear more showy; he knew his hand (note 9)'.
Picture purchased by the Gallery.
The journal ‘News of Literature and Fashion’ for the 15 April of that year remarks: 'The real truth is that the ‘Bacchus and Ariadne’ has had a great many tricks played with it. When at Rome, it was considered a fine picture, but exceedingly brown. When it came to England it was cleaned so effectually as to have become a perfectly blue picture, and now it has relapsed into dinginess again [...] .
Eastlake's initial entry for the picture in the Manuscript Catalogue concerning conservation: 'Lined: at what period uncertain. Cleaned to a certain extent by Mr. J. Seguier (note 10) in October 1846. See Return respecting pictures cleaned; Report from the Select Committee on the National Gallery, 1853, p.748. See also minutes of the Trustees (Parliamentary Paper No.40,1847, pp.15,19) – Gallery Varnish 1846' (note 11).
'Discoloured and decayed varnish removed so far as was thought prudent.' (Appendix to ‘Report from the Select Committee on the National Gallery’, 1853.) The remark refers to Seguier's cleaning operation of 1846 mentioned above. Before the Select Committee Mr. Retra Bolton, a picture-cleaner, stated his belief that the 'Bacchus' had been hurt by the Gallery Varnish: 'I remember that picture looking fresher a great deal. I do think the oil varnish has acted upon that picture: it is getting streamy and smurky [sic] about the skies.'
Reported as having been lined, at what period uncertain. Repairs visible in the left shoulder, neck and breast of Bacchus. Effects of discoloured varnish (probably not completely removed in 1846) apparent in the sky, 'but not so as to injure the appearance'. Canvas partially detached from the lining in the upper left corner, also in the upper right corner.
Placed under glass.
The varnish revived by the Pettenkofer process (note 12).
'The picture was examined as to the "buckling" in the upper left-hand corner in August; the lining canvas being reported by Morrill (note 13) to be in a bad state, the picture was relined [double lined by Morrill, for which the bill exists in the Conservation Department's files]. The surface of the varnish was then taken off by Buttery with the finger (note 14), one or two very slight injuries repaired, and the picture was re-varnished with mastic, under my eyes' [signed E.J. POYNTER (note 15) ].
The two lining canvases removed by Morrill revealing that the back of the original canvas 'had at some period been covered with paint' [which was probably in fact an old adhesive, containing some lead white, from an even earlier lining]. Relined with a single canvas. The then Director, A. M. Daniel 'expressed the definite desire that the surface should be touched as little as possible, as I in no way wished the picture to be cleaned nor the old varnish to be removed', in spite of a warning from the restorer that in the process of relining the varnish 'might perish and become opaque'.
The new lining seems not to have been a success, for there exists pasted in the Manuscript Catalogue a further typewritten note signed by A. M. Daniel describing how, while Mr Morrill the restorer had been gluing the original canvas onto the lining, a blister had formed on the foreground beneath the feet of one of the Bacchante. Morrill had considered the only course to adopt-though some might consider it a drastic one-was to cut the blister, thereby releasing the pressure within, 'before it spread further'. This cut, through the original canvas and about 14 inches long, could easily be seen (Fig. 1) before the 1967–1969 restoration. Morrill was strongly of the opinion-and his views were to be confirmed during the most recent examination and treatment of the picture-that the root of the trouble was the thin coat of paint, or paint-like material, on the back of the original canvas, which prevented 'the proper action of the glue in making at once adherent the original canvas and the lining'.
Unfortunately the recurring malady of flaking paint seems not to have been cured in the long-term by this latest relining:
June and November. Flaking paint secured by Morrill.
Loose paint laid by Morrill.
Polished by Vallance (note 16).
Varnish along right edge revived by Lucas.
Fine flaking at top treated with wax by Woods.
In 1938 a report on the state of the painting was made by H. Ruhemann, then Consultant Restorer, who after detailing the well-preserved areas, paint losses, damages and retouchings, concluded: 'Could be greatly improved, but it would be an enormous job'.
In 1948 a very full report of the condition at that time was made by Philip Hendy, then Director, in collaboration with conservation staff. The observations and proposals for treatment, including removal of old varnish, laying of loose paint, impregnation of ground and paint with an adhesive, probably combined with relining, were not in fact very different from those to be made in 1967. The optimistic tone of the report suggests that it was expected that the proposals would very soon be put into practice, but it was not to be. In 1947–1948 there was held the 'Cleaned Pictures Exhibition' consisting of all the National Gallery pictures cleaned since 1936 (a total of seventy works), together with related photographs and background information, and catalogue (note 17). To some (including the authors) the 'Cleaned Pictures Exhibition' was a revelation; to others it was an outrage. It has to be recalled that this comparatively small group of cleaned paintings at that time stood out like beacons among the rest of the collection, many of which still bore the notorious 'Gallery Varnish' (note 11), and against the rather dingy post-war decor. Moreover, several generations of Gallery visitors had grown up accustomed to seeing pictures in an uncleaned state. The position is now reversed, for not only in the National Gallery, but in a good many of the great galleries of the world and in major international exhibitions, it is the uncleaned pictures which tend disturbingly to stand out. Although an international committee, the Weaver Committee (note 18), set up in 1947 'to inquire into and report on the Safety of the methods and materials used in the cleaning of pictures at the National Gallery', affirmed that the safety of the pictures had never been jeopardized by cleaning, the storm of controversy subsided only gradually, leaving an atmosphere not conducive to starting on a major restoration of one of the Gallery's major masterpieces and the project was shelved until 1967. In the meantime anxiety about possible further deterioration of the painting did not, however, abate, for another longish report cataloguing the by now familiar symptoms of discoloured varnish, disfiguring retouchings, paint losses and further incipient flaking was entered in the Conservation Dossier in 1952.