Artwatch UK

Posts tagged “Helmut Ruhemann

A National Gallery restoration that repudiates earlier National Gallery restorations

When major museums acquire major pictures, they invariably take additional technical and artistic possession of them through restorations. By transforming pictures’ appearances, museum staffs lay claim to an exclusive up-to-the-minute knowledge of a picture’s material and artistic traits that renders all earlier studies obsolete and activates use of the possessive “our” – as in “our Duccio” or “our Artemisia Gentileschi”. For much-criticised museums like the National Gallery and the Metropolitan Museum of Art, New York, the introduction of a well-preserved picture within a collection risks spotlighting in-house restoration damage – as might well have happened, for example, had the Met exhibited its newly acquired, fabulously well-preserved Velazquez portrait Juan de Pareja and its Perino del Vaga The Holy Family with the Infant St John the Baptist before restoring them. Today, the National Gallery seeks to counter long-standing criticisms by allowing its restorers to present their own interventions and purposes through broadcast social media. In a press release of 2 August 2019, the gallery’s Director of Collections and Research, Caroline Campbell, said of a restored panel painting:

“The National Gallery is one of just a handful of institutions across the world that is able to carry out painting conservation of this complexity. As this work has been carried out behind closed doors, this display is an opportunity to share this expertise with the public and also to celebrate our conservation skills, in a similar way to how we shared the conservation of our Artemisia Gentileschi self-portrait via a series of films.”

Such hubristic public relations manoeuvres are risky. As Michel Favre-Felix, painter and President of ARIPA (Association Internationale pour le Respect de l’Intégrité du Patrimoine Artistique), demonstrates below, restoration errors are still to be encountered among the nation’s pictures and the restorers’ own explanations leave conspicuously unaddressed questions. [M.D.]

Above, Fig. 1: Left, the National Gallery’s Artemisia Gentileschi Self-portrait as Saint Catherine of Alexandria, as presented by the Paris-based auctioneer Christophe Joron-Derem for the 19 December 2017 auction; right, as subsequently restored by the National Gallery.

Michel Favre-Felix writes:

Artemisia Gentileschi’s Self-portrait as Saint Catherine of Alexandria, which was acquired two years ago for £3.6 million (a record for the artist), has already become a new iconic painting of the National Gallery. To the appeal of a self-portrait by the most celebrated female painter of the 17th century, the picture (above, Fig. 1) adds a telling symbolic aura. Commentators have not failed to underline that this martyred saint Catherine, holding the instrument of her ordeal – the miraculously broken spiked wheel – persevering in her faith in the midst of persecution and rewarded with eternal salvation, mirrors the shattering life-story of Artemisia herself, young victim of a rape, maintaining her testimony under torture and finally triumphing in her female artist career. This emblematic portrait is the central feature in the present major exhibition of her work – the first ever in UK – “Artemisia”, National Gallery, London WC2, until 24 January 2021.

Just two weeks after announcing the purchase, in July 2018, the National Gallery began posting on YouTube the first of what became a long series of videos of the restoration in progress (see the list at the end of this article). No fewer than four of them deal with the picture’s cleaning – the need for it (which will be discussed below); the expected effects; its progress and its results.

Such a pedagogic/celebratory (to re-use Caroline Campbell’s expression) public programme is unprecedented. Hitherto, if the Gallery decided to communicate an account of one of its restorations it usually appeared in its scholarly Technical Bulletin, with a strong emphasis on the scientific analysis of the picture’s material structure and a minimal part, if any, given to the hands-on cleaning process itself. The set of YouTube videos exactly reverses that relationship.

As in political discourses, vocabulary plays a key role and carries far-reaching meanings. Old traditional terms might surface, as when the curator, Letizia Treves, observes rather innocently that ‘the picture is quite dirty’, expressing her expectations from its forthcoming cleaning (in Who was… 4:18). ‘Dirty’ is the customary loaded codeword used to justify a total varnish removal. It leaves no room for investigations or nuances: ‘dirt’ cannot reasonably be even partially kept on a painting; it must be entirely wiped out. (See Fig. 1, above, left, for the pre-restoration condition.)

Larry Keith’s expressions are purposefully different. He not only restrains himself from using the loaded and derogatory, non-scientific term ‘dirt’ to describe what is in reality a coat of old varnishes, but he takes care to amend the ambiguous twin-word of ‘cleaning’, by changing its sense, at the start of his talk (in Cleaning… 0:25): ‘Cleaning meaning the… [short pause] …reduction of the old discoloured degraded varnishes’ (“reduction” being the operative word). This singular short pause in his otherwise fluent and dynamic speech is eloquent.

A closer look shows that this change of definition has matured over several years. The cleaning of the Virgin of the Rocks, in 2009/2010, was already presented as a ‘reduction’ [Endnote 1], although this peculiar aspect went rather unnoticed at the time [2]. Earlier, when commenting on the restoration of Guido Reni’s The Adoration of the Shepherds in 2007, Larry Keith mentioned that to clean might be ‘to remove or reduce the old discoloured varnishes’ [3]. If cleaning now means a reduction rather than an elimination, this new position has generated a number of unaddressed questions.

1) First, what does this policy change reveal about the systematic total cleanings made in the past? What happened to the previous certainties on which the gallery’s conservation policy was grounded and which had served to authorise its restorations? Since the post-Second World War ‘Great Picture Cleaning Controversy’, the gallery’s conservation department maintained, against its national and international critics, that a complete removal of varnish was the only way to establish the true, objective, unfalsified state of a painting, and to recover as closely as possible its original appearance as created by the artist. This was not held to be one option among others. It was the inescapable and inevitable conclusion of methodical reasoning itself. The leading proponent of this policy, the de facto chief restorer, Helmut Ruhemann, went so far as to list nine ‘main Arguments against Part Cleaning’ in a crucial chapter of his 1968 book The Cleaning of Paintings (pp. 214-217), which had set the Gallery’s official institutional methodology for more than half a century – and still exerts an influence.

Part-cleaning was not only ruled out in theory but was held to be both unfeasible and deceiving in practice. Ruhemann’s strongest and most persuasive arguments were technical ones. Using the authority of the practitioner, he asserted that a reduction of the varnishes regularly produces an uneven result leaving disruptive and disfiguring ‘patches’ scattered all over the paint. He claimed that a half-way cleaning was arbitrary and inevitably imprecise, the restorer being ‘condemned to groping in the dark’. He stressed that, if there was some old varnish left, it would be impossible to suppress all the faulty and distorting old retouching that might lie underneath. Moreover, he added that the new retouches would never correctly match the still imperfectly cleaned paint.

This argumentation, unchallenged for decades, happens to have been refuted by Larry Keith’s recent practical demonstration. Although Keith used traditional means (no revolution in tools or solvents or monitoring is used in the Gallery) his ‘reduction’ did not generate the Ruhemann-predicted failures: it neither failed to suppress the old retouches nor to avoid uneven ‘patches’ – nor even failed to achieve perfectly matching indiscernible new retouches.

2) What is the reason for adopting partial cleaning today? On the one hand, in hindsight, we can see that the previous policy of total cleaning was based on spurious arguments but, on the other, it is striking that no revised or new justification is provided in support of the present policy.

Why is it now considered to be appropriate, required – or even essential – to keep a part of the old so-called ‘degraded and discoloured’ varnishes on this painting? Is it to serve as a guarantee for the safety of the paint and possible original glazes underneath when subjected to the cleaning with solvents? Does this last layer of old varnish bear a meaningful aesthetic and/or historic value that ought to be preserved? Does the remnant of the surface coating constitute part of the artistic authenticity of the work of art? Keith provides no indication at all. A full range of arguments in favour of part-way cleaning have been put forward elsewhere since the 1950s by connoisseurs, critics and art historians but Keith refers to none.

In reality these questions concern a majority of works because this portrait is not at all an exceptional case. It was, at the time of its acquisition, in a ‘standard’ condition that is common to so many paintings from past centuries that have been subjected to restorations: from the Gallery’s report it turns out that its surface bore the usual old retouching, and its canvas, already relined as was customary in the past, had since suffered a small tear and will be relined anew.

Acknowledging the ‘reduction’ of the varnishes as the best possible care for this painting implies/concedes that it should have been similarly prescribed and applied successfully to so many comparable paintings, affected by the same usual damages, but which were radically cleaned at the National Gallery.

3) Larry Keith never explains in his videos why he chooses to thin rather than to remove the coat of ‘degraded’ varnish, as was the rule before. He simply strives to show why the old varnish needed a treatment and to demonstrate that he achieved ‘key improvements’ on the test areas where it has been reduced.

About the state of the varnish he draws a distinction, not without reason, between two effects: ‘these old varnishes when they degrade, they turn yellow and they turn foggy…’

That is true in a general way, but it is precisely from there that reflections should begin, because while the first is the natural, predictable, regular evolution of traditional materials, the latter is an unfortunate degradation that preventive care could avoid.

Above, Fig. 2: Screen capture from the video “Cleaning…” – See the full linked-list of videos below.

On this first issue, that of yellowing, the explanations are especially puzzling:

[in Cleaning… 1:27] “You see that where the varnishes have been reduced, the overall tonalities of the picture are much less yellow. The fingers [on the left] are emerging rather pink, instead of this kind of yellow colour [on the right] and I am sure that will become more evident as we move across the picture…”

These comments are puzzling because they hardly fit with what is shown. The old varnish did not turn the skin tonalities markedly and disturbingly yellow (compare the back of the hand on the right with the old varnish on, to the ‘reduced’ one on the fingers on the left at Fig. 2 above), and it is indeed anything but ‘evident’ that it distorted the perception of the colours. It may be recalled that in December 2017, during the presentation of the painting before its auction in Paris, the expert Eric Turquin praised the ‘subtle pinks’ – in his own words – he had no trouble distinguishing in the flesh tones of the portrait with the old varnish on [4].

Above, Fig. 3: Photograph (detail) from the Hyperallergic site, 12 July 2018, showing the “Artemisia” exhibition curator, Letizia Treves, facing the self-portrait before cleaning began. Although top lighting caused a pale reflection on the canvas, lightening the dark tones, it can be seen here that Artemisia’s flesh tones are not so much yellowish as close in their pinkness to the curator’s own natural colouring.

Above, Fig. 4: The restorer Larry Keith, examining the painting before cleaning began, as shown on BBC News 6 July 2018.

The above photos published in July 2018, at the very start of the intervention, in which spectators are present confirm that the variety of colours in the painting was clearly perceptible: the shades of pink of the face, the cream tone of the headscarf, the Naples yellow of the palm leaf or the ochre of the wood read easily and naturally. One can observe that there was no oppressing monochrome veil distorting the shades of the portrait, which were quite close to the natural skin tones of the viewers, as the photographs testify (Figs. 3 and 4).

Surprisingly, if not tendentiously, Keith even evokes an ‘accumulation of varnishes’, which he ventures would result from ‘many restorations that have probably occurred’ in the past (in Cleaning… 4:35). ‘Many’ is merely hypothetical since the history of this painting is totally unknown between the years of its creation, circa 1615-1617, and the 1940s when it resurfaced, only to be quietly kept in a French family (Pes, J. 2018).

Looking at the photographs of the initial state, it is difficult to deduce a superimposition of many added layers. Fortunately, this will be checked since Keith has announced that ‘minuscule samples [will] help us understand the layers structure of the accumulation of varnishes’ (in Cleaning… 4:35). Fine. It will be of great interest for the public and the experts that the result of this investigation by the laboratory be disclosed: how many layers of old varnishes? To what total thickness? Until these results are established and cited the idea of an ‘accumulation’ of layers of varnish will remain a puzzling assumption.

4) Beside the issue of yellowing – that he admitted not to be ‘evident’ – Keith places a greater emphasize on the second, undisputable, aspect of the picture condition, that of the varnish getting foggy. This loss of its transparency is, by contrast, plainly documented.

Even during the presentation at the 2017 auction in Paris, while the subtlety of the colours was praised, the ‘dullness of the varnish’ was nonetheless underlined and attributed to the fact that the painting had remained in the same family for several generations.

The video illustrates the consequences of this phenomenon (in Cleaning… from 1:40):

“… where [the foggy varnishes] are over the darker tones, the darker tones become quite a bit lighter. You can see that here, with that sort of hazy presence. And whereas down here where I started reducing the old varnishes, you can see the darker colours are much darker and the range from light to dark is much enhanced. And I think this helps you understand how [Artemisia] has laid out the folds, and helps you understand what is in front of what.

“…I think the thing here [in the ‘reduction’ in progress] that is most significant and really very rewarding is to see now the range from light to dark, which [Artemisia] has used, and her modelling of forms, which gives this sculptural presence.”

Indeed, Artemisia’s artistic expression rests on the illusion of spatial depth and on the convincing impression of three-dimensional figures. And this pictorial achievement is only displayed when the half-tones, dark values and contrasts have their full effect, which requires a good transparency of the varnish final layer.

It is hence plainly justified to try to regain this fundamental quality. However, in the case of this painting, such faint cloudiness is a common and rather benign alteration caused by humidity (that is to say, by a lack of prevention from its keepers). Physically, this phenomenon results from the scattering of light – not exactly on the ‘varnish’s own kind of fine cracks’ as it is said rather simplistically in the video – but on a multitude of micro-fissures, much smaller than usual cracks, that have developed within the varnish film at a microscopic scale that is invisible to the naked eye.

Above, Fig. 5: Above, Fig. 5: detail of Artemisia’s arm, showing un-thinned (slightly dull) varnish on the right and thinned varnish on the left.

As can be seen on the video, the thinning of the varnish has cleared the cloudy effect and has thus enhanced saturation and contrasts [above, Fig. 5]. Yet, the cause/effect relationship is not that simple. The dissipation of the hazy opacity is the result of a specific physical process: it comes from the ‘closing’ of the micro-fissures, which is obtained through the momentary softening and swelling of the varnish film when suitable solvents are applied to it. Once the solvent has evaporated, the micro-fissures have closed and so, vanished. Since the ‘reduction’ was done with solvents, their penetration into the varnish film provoked the swelling/closing result. Thus, this was a linked side-effect and it would not have been necessary to thin the entire varnish layer for that to happen. For this kind of light haziness, a simple exposure of a varnish surface to an appropriate solvent, at much lower levels – i.e. ethanol in form of vapours – without any ‘reduction’, could have produced the same positive result (Pfister, P. 2011, Demuth, P. 2001): the saturation of colours; the in-depth setting of the figure; the sculptural modelling created by Artemisia, would all have been recovered.

Of course, when such a minimal treatment is chosen, the tonality of the varnish remains unchanged, since its thickness is undisturbed even as its transparency is regained.

Knowing this, we realize that there is confusion between the two results. In truth, a physical reduction was not essential to recover the range of values from light to dark and modelling of forms intended by the artist, which could have been achieved otherwise. Essentially, the thinning of the varnish was used principally and specifically to obtain the ‘much less yellow’ overall tone. This result is held – in Larry Keith’s account – to be such an obvious improvement as to require no further justification. Yet, it does – and we see below why it needs questioning.

5) The transparency is a basic undisputed requirement for this varnish (as for any other). But what is the justification for making it ‘much less yellow’?

When we leave aside our own era’s cultural preferences and consider the materials and varnishing practices that prevailed in the XVIIth century, we realize that the (disparaged) ‘old varnish’ found on this painting had the best chance of resembling the original finished appearance as made by Artemisia herself.

Above, Fig. 6: A section of de Mayerne’s text (Folio 151r) mentioning Artemisia Gentileschi and her varnish.

Throughout these supposedly informative and instructive videos it is striking that no reference is ever made to the kind of varnish that would have been used by the artist herself, or, even, to those that were common in her circle and time in Italy. This omission is hard to justify since relevant historical and technical references have survived and are accessible. For example, Turquet de Mayerne’s manuscript notebook (written between 1620 and 1646), which is the main historic testimony and source of information on the painting techniques of this period, contains a famous reference to an ‘amber varnish’ [5], ascribed to both Artemisia (active c. 1610-1653) and her father Orazio Gentileschi (active c. 1587 -1639) – see Fig. 6, above. De Mayerne specifies that this varnish had a strong reddish tone and was used by the instrument makers to varnish lutes [6].

It should be borne in mind that, at that time, in the absence of precise identification, the term ‘amber’ (otherwise called ‘c(h)arabe’) encompassed a group of resins that were close by their consistency, colour, workability and effect – and among which were chiefly the different semi-fossil resins that we now classify as copals, which range from semi-hard to hard and are easier to dissolve than true fossilized amber (Leonard et al. 2001, Holmes, M. 1999).

Furthermore, the expression amber varnish ‘coming from Venice, with which they varnish lutes’, added in the passage on Orazio (Folio 9v), most probably indicates a ready-made product. At that time in Italy many varnish formulations were no longer made in the artists workshops but prepared and sold by colours merchants. The painter Gian Battista Volpato quotes the ‘amber varnish’ as one of them [7]. De Mayerne states that a so-called ‘Oil of Amber from Venice’ (that is, a fat varnish made of ‘amber’ dissolved in a possibly larger proportion of oil), which he supposes to be the one used by Orazio, was sold in every Italian colour shop [8]. The main point is that these prepared varnishes formed a dry film that approached the legendary hardness of amber and had a similar golden-brassy colour. Some rosin (colophony) could be added, which was useful for improving the working properties of the mixtures (Leonard et al. 2001). Its marked orange hue would also increase the warm tonality of the whole – see Fig. 7 below.

Above, Fig. 7: Colophony (or rosin, resinous part remaining after the essential oil has been extracted from the balsam of Pinus maritima Lamb. by distillation.)

It is mentioned that Artemisia mixed her ‘amber’ varnish with oil and spread the blend as an intermediary layer upon the already dried parts of her work in progress, before continuing to paint (Folio 151r). This method, commonly called ‘oiling-out’, has three benefits for reworking: it brings back the initial saturation of the first colours that might have turned dull when drying; it enables a fluent application of the later colours; and, it promotes their physical adhesion to the ones beneath.

Concerning Orazio, de Mayerne notes that he used to add a drop of ‘amber’ varnish directly to his colours on his palette – especially to the ones of the flesh tones – in order to make them more ductile and quicker to dry (Folio 9v).

Was it also chosen as final varnish? The use of the same compound for mixing with colours, for intermediary ‘oiling-out’ and for final varnishing is indeed consistent with what is known of painters’ practices at the time. Examinations of paintings by Caravaggio (of whom Orazio was a disciple) have shown that remains of his final varnish – resin in oil – were similar to the ‘oiling-out’ layers found in his paint structure (Arciprete, B. 2004).On the same folio (151r) where de Mayern mentions Artemisia’s oiling-out method, he reports on another ‘charabe’ varnish, which can be used ‘for varnishing and for mixing on the palette with the colours’ [9].

Moreover, a discovery made by the Getty Conservation Institute in 2000 confirms that Orazio also adopted an ‘amber type’ varnish of his final coating. Found on one of his painting (Lot and his Daughters, J. Paul Getty Museum, Los Angeles) executed about 1622, this rare original varnish proved to be composed of Manilla copal and rosin, precisely (Leonard et al. 2001) [Figs. 7 and 8].

Above, Fig. 8: Manilla Copal (from Agathis dammara Lamb.)

This tangible historical/material evidence of what was an ‘amber-like’ formulation provides a precious testimony of its visual effect on the picture: it displayed a notable warm golden tone over the parts where it was still present (see Figs. 9 and 10 below). Given that Artemisia learnt to paint in her father’s studio, it is beyond doubt that Orazio would have shared both his materials and his practices with his daughter.

Above, Fig. 9: The effect of Orazio’s varnish on the sky of his Lot and his Daughters (in The Burlington Magazine’s article, Vol CXLII n°1174, p.5.)

Above, Fig. 10: Macro-photograph of the varnished sky. Note the bright blue colour of the paint that appears in some spots where the ‘amber-like’ varnish is missing (from the same Burlington Magazine article, p.9.)

In addition to those clues, there is the certainty that Artemisia’s varnish could only have been composed with resins among those of her time (the end of 16th/ first half of 17th centuries): sandarac; oleoresins balsams from the silver fir, the larch or the spruce; colophony; mastic; copals, with or without oil [10] (Figs. 7, 8, 11 and 12). Reconstructions of historical recipes with such ingredients, prepared and applied following traditional methods are converging to show that they provided a natural warm tone – a ‘golden glow’ – that moreover increased surprisingly quickly (Favre-Félix, M. 2017, Carlyle, L. 2005, CCI 1994) (Fig. 13).

Above, Fig. 11: Strasbourg turpentine (balsam – oleoresine – of the silver fir, Abies pectinata DC. – from Kremer Pigmente.)

Above, Fig. 12: Sandarac (from Tetraclinis articulata Mast.)

Above, Fig. 13:As an example, the reconstruction of an historical recipe, using one resin and one oleoresin – a type that became increasingly prevalent from the end of the 16th and throughout the 17th centuries – showed a notable increase of its natural coloration within a short time. 

Thus, there lies a major contradiction of modern restoration: the profession asserts a strict adherence to the scientific study of the artists’ materials and techniques, but continues to ignore the technical characteristics of the varnishes that are known to have been used in those centuries. Further, while it aims to present paintings as close as possible to the artists’ conception it still declines to take into account how their paintings had once looked with their original final layer on, and it persists in eliminating the ‘yellow tone’ of any varnish encountered on old master paintings.

CODA:

A last video deals with the significant choice of a frame for Artemisia’s self-portrait. The Head of Framing, Peter Schade, points out that an authentic frame from the 16th century – wood-carved, painted or gilded – will always surpass any copy of it, even those that look to be perfect reproductions. He makes the following crucial remark [Choosing… 8:45]: “We always carry the baggage of modernity, of our time… And that gets always in some way transferred into reproduction frames. Usually, we don’t see it now but you can look it back at the history of frame reproductions, in the gallery as well, and [see that with] most reproduction frames, after twenty, thirty years they don’t match up to originals.”

Larry Keith had then to admit – albeit in carefully chosen words – that the same rule of unwilling, modern distortion applies to restoration:

“[9:12] …It is the same thing about how we… decisions we make about restoration itself, you know. We think we try to be… I guess what we can say now, is that we are very transparent about the decision-making process but it’s definitely an interpretation all the way down the line”.

Restoration being a contemporary “interpretation” of the work of the past, transparency is essential, and transparency implies clear explanations for the present and for the older interventions. But, strikingly, Larry Keith has not explained in any way the main justification for reducing rather than eliminating surviving varnishes. With regard to the use of retouching – e.g. in the reconstruction of the cropped top of the crown – his presentation and discussions are fair (see Reconstructing… and Retouching…) But on matters of cleaning and varnish this essay’s conspicuous technical, aesthetic and historical documentary omissions testify to an enduring institutional avoidance of transparency on the most vital artistic questions of art conservation at the National Gallery.

Above, Fig. 14: Artemisia’s Self-portrait, left, as in 2017 at auction; centre, same state but as provided by the National Gallery to the press in July 2018, before cleaning; and, right, as at the end of 2018 at the National Gallery, after cleaning and restoration.

Michel Favre-Felix, 9 October 2020.

THE NATIONAL GALLERY RESTORATION VIDEOS:

1) Starting the restoration of Artemisia Gentileschi’s ‘Self Portrait’ – Now entitled: “The art restoration plan for Artemisia Gentileschi’s ‘Self Portrait'” – as posted on the 20th of July 2018.

2) Cleaning Artemisia Gentileschi’s ‘Self Portrait’ – as posted on the 27th of July 2018.

3) ‘It’s such a 17th century thing to do’ | Cleaning Artemisia Gentileschi’s ‘Self Portrait’ – as posted on the 3rd of August 2018.

4) Who was Artemisia Gentileschi? – as posted on the 20th of August 2018.

5) Finishing the cleaning | Cleaning Artemisia’s ‘Self Portrait’ – as posted on the 30th of August 2018.

6) Repairing a 17th century canvas – as posted on the 10th of September 2018.

7) Applying the moisture treatment – as posted on the 21st of September 2018.

8) Finishing the relining – as posted on the 2nd of October 2018.

9) Reconstructing the unusual composition of Artemisia’s ‘Self Portrait’ – as posted on the 9th of October 2018.

10) Retouching a 17th century painting – as posted on the 13th of November 2018.

11) Choosing a frame – as posted on the 26th of November 2018.

12) Framing Artemisia – as posted on the 14th of December 2018.

ENDNOTES:

[1] “Indeed not all the old varnish was removed – it was simply reduced to a level which helps us to fully appreciate the painting.” (Larry Keith – Restoring Leonardo, National Gallery website.)

[2] “By removing the ugly varnish…” Jonathan Jones commenting on this cleaning in The Guardian, 13 July 2010. When reviewing the National Gallery’s restoration of its Leonardo Virgin of the Rocks, Jones expressed delight that the painting had been “freed from an amber prison”.

[3] National Gallery Podcast: Restoring Reni’s ‘Adoration of the Shepherds’, 1 :48.

[4] ARTECENTRO – Artemisia Gentileschi, Sainte Catherine d’Alexandrie, vente le 19 décembre 2017. Time 2: 47.

[5] ‘Vernix d’Ambre venant de Venise’ (Sloane MS 2052 Folio 9v).

[6] ‘Ce Vernix est fort rouge & est celuy des faiseurs de Luths’ (Sloane MS 2052 Folio 150 v).

[7] ‘quella d’ambra si compra, quella di mastice la facio io’ (Merrrifield, M.P, p. 743).

[8] ‘Chés touts les vendeurs de couleurs en Italie on vend une huile espaisse, qu’ils appellent Huile d’Ambre de Venise […] Je croy que c’est ceste huyle dont m’a parlé & se sert Gentileschij ’ (Sloane MS 2052 folio 146v).

[9] ‘Et pour vernir: & pour mesler sur la palette avec les couleurs’ (Sloane MS 2052 folio 151r).

[10] Such a choice of resins for varnishes is also noted by Van Dyck, at the same period, on a folio of a sketchbook: fir balsam, colophony, unspecified ‘vernizia’ and amber varnish (Kirby, J. 1999, p. 13).

BIBLIOGRAPHY:

Arciprete, B. (2004), ‘Il restauro’, La Flagellazione di Caravaggio, il Restauro, Electa Napoli.

Carlyle, L. (2005) ‘Representing authentic surfaces for oil paintings: experiments with 18th and 19th-century varnish recipes’, Art of the Past, Sources and Reconstructions. Proceedings of the first symposium of the Art Technological Source Research study group. Archetype Publications.

CCI (1994) Varnishes: Authenticity and Permanence Workshop, Canadian Conservation Institute, (Reviewed by Neil Cockerline).

Christiansen, K., Mann, J. W. (2001) Orazio and Artemisia Gentileschi – New York Metropolitan Museum of Art, Yale University Press, New Haven.

De Mayerne, T. Turquet, (1620) Pictoria Sculptoria & quae subalternarum artium, British Library, Sloane MS 2052. Trancription in Berger, E. (1901) Quellen für Maltechnik Während der Renaissance und Deren Folgezeit (XVI.-XVIII. Jahrhundert), München.

Demuth, P. (2001) ‘Regeneration of blanched natural resin varnishes with solvent vapour’ Hochschule für Bildende Künste – Dresden/ The ENCoRE Symposium: Recent development in conservation-restoration research 19-21 June 2001.

Eastlake, C. L., (1847) Methods and Materials of Painting, Dover Publications, New York (2001)

Favre-Félix, M. ‘On the recipe for a varnish used by El Greco’, Conservar Património 26 (2017) pp. 37-49 – ARP – Associação Profissional de Conservadores-Restauradores de Portugal http://revista.arp.org.pt/pdf/2016023.pdf

Holmes, M. (1999), ‘Amber Varnish and the Technique of the Gentileschi’, in Artemisia Gentileschi and the Authority of Art: critical reading and catalogue raisonné, R. Ward Bissel, Pennsylvania State University Press, pp. 169-182.

Kirby, J. (1999) ‘The Painter’s Trade in the Seventeenth Century: Theory and Practice’- National Gallery Technical Bulletin, Vol 20.

Leonard M., Khandekar N., Carr D.W. (2001) ‘Amber Varnish and Orazio Gentileschi’s Lot and his Daughters ’, The Burlington Magazine Vol. CXLIII, pp. 4-10

Merrifield, M. P. (1849) Medieval and Renaissance Treatises on the Arts of Painting, Dover Publications, New York (1999).

Pes, J. (2018) ‘The National Gallery’s New Artemisia Gentileschi Should Be a Triumph – But Clouds Are Forming Over Its Ownership During WWII’, December 12, 2018, News-artnet.com.

Pfister, P. (2011) ‘Régénération : l’emploi des vapeurs d’alcool et les dangers des alcools liquides’ / Kunsthaus – Zürich / Nuances 42/43, pp. 24-29.

Ruhemann, H. (1968) The Cleaning of Paintings. Problems & Potentialities. Praeger Publishers.


Good Science; Over-Reaching Science; Over-Promoted Science.

24 February 2014

On February 10th the Daily Telegraph published a letter from a professor of chemistry at University College London (Robin J. H. Clark) questioning the relationship between art and science in general terms and with regard to a supposed Chagall painting featured on a recent BBC Fake or Fortune television programme. Prof. Clark expressed particular concern over art world failures to heed the testimony of available scientific techniques.

In the late 1980s the UCL chemistry department had developed a non-invasive technique (“Raman microscopy”) for identifying both natural and synthetic pigments within paintings. Because the latter have known dates of invention, their presence in a picture can establish the earliest date at which it could have been produced. This technique is said by Prof. Clark to have been known to Sotheby’s by 1992. The Chagall painting, he pointed out, could have been exposed as a fake at any point in the last 20 years. He further reported that the painting was exposed as a forgery in his UCL laboratory in July last year in the presence of its owners and the presenters of Fake or Fortune:

“I am disappointed that neither of the presenters of Fake or Fortune made this clear. The conclusion that the painting is a forgery is based on our spectroscopic results, which showed that at least two of the key pigments had not been synthesized until the late Thirties, putting the earliest date for the painting at 1938, long after the supposed date of 1909-10.”

Because of the unequivocal nature of those technical findings, Prof. Clark (rightly) observed that the Chagall Committee in Paris, to which the painting was sent, had no option but to confirm the forgery. He also asked how art historians might be encouraged to read science journals so as be informed about “significant developments in science as applied to arts”. In part, his question is fair and urgent. The art market’s notorious governing trade dictum is caveat emptor (buyer beware) – while auctioneers and dealers may take every pain to verify their claims, it is ultimately for buyers to satisfy themselves that attributions and conditions are as described. Auctioneers can only submit works to (possibly disqualifying) technical analysis with owners’ permission. Dealers who buy at auctions almost invariably have works restored but are not required, when selling works on, to disclose which if any tests may have been run.

Support on the extent to which scientific (and also historical and visual) evidence is ignored or manipulated in the interests of “boosting financial rewards in attributing paintings to particular masters” was given in an Observer interview on February 23rd (“Revelealed: the art experts who pass fakes as authentic”) by Professor Martin Kemp, a Leonardo specialist. In the same report by Dalya Alberge, Nicholas Eastaugh, a leading independent scientist (of Art Access and Research), described the present climate as being both without standards and “totally unregulated. It’s a Wild West.”

However, much as we sympathised with Prof. Clark’s impatience with some art world practices, we could not endorse his call for a blanket acceptance of all scientific methods presently being applied to works of art. As we put it in a letter to the Daily Telegraph (published 12 February):

“Professor Robin Clark (letters February 10) calls for developments in science to be applied to art. If sound science is underused by the art trade, more questionable ‘scientific studies’ have been used for many years to offer assurances that picture-cleaners’ solvents have been a safe method of stripping varnishes and repaint from old pictures. As the current issue of the journal of the International Institute for Conservation of Historic and Artistic Works makes clear, the understanding in the art and museum world since the Sixties of how solvents work has been seriously flawed scientifically. Because important intermolecular interactions have been ignored, the theoretical model used cannot predict, as assumed, the actions of solvents on the underlying paints.”

History teaches that the many cumulative “scientific” defences of restorations have best been treated with scepticism. In 1977 Kenneth Clark admitted founding the National Gallery’s conservation science department precisely to bamboozle critics and dupe the public. In later years the Gallery pioneered a new mongrel discipline known as Technical Art History in which curators, conservators and conservation scientists pool expertises so as to arrive at some seemingly “scientifically underpinned” consensus on aesthetic decisions. In reality curators were glossing authority already-ceded to restorers. As the National Gallery restorer Helmut Ruhemann wrote in 1968: “Although the art historians in charge of pictures are officially responsible for the policies regarding cleaning, they naturally form their ideas in the first place from what they are told by their restorers.”

In its guides to conservation the National Gallery presently claims that while its restorations are carried out for aesthetic rather than conservation purposes, and while each restorer imposes a personal aesthetic taste on pictures, it considers all aesthetically various outcomes to be equally valid so long as they have been carried out “safely”. The contention that the (claimed) safety of cleaning methods can underwrite conflicting aesthetic outcomes is a non sequitur. Besides which, no claims have proved more unreliable than those of cleaning solvents’ safety.

The crucial and sometimes wilfully over-looked cultural truth is that there are no properly scientific means of comprehending art’s variously created aesthetic values and relationships. When reiterating this point in our post of 7 February 2014 (“From the Horse’s Mouth ~ Seventy years of worthless ‘science’ and reassurances on the safety of picture cleaning solvents”) we were able to disclose the most recent and most damning evidence of the un-soundness of past scientific endorsements of picture-cleaning solvents.

Notwithstanding these spectacular technical reverses, this month the press has been chocked with uncritical “Good News” accounts of scientific advances in the arts. Most newspapers and the BBC carried claims that scientists had “digitally reconstructed” the original appearance of a Renoir painting in which a former pink background had faded. By coincidence, this claimed miraculous virtual recovery had also been made by “a technique known as Surface-Enhanced Raman Spectroscopy (SERS)” carried out at the Art Institute of Chicago.

The BBC reported that “Northwestern University chemist Prof Richard Van Duyne pioneered SERS. He said the Renoir demonstrated why the Raman technique was fast becoming an invaluable tool for studying artworks: ‘You get tremendous information about the origins of the painting, the techniques of the artist, an understanding of the fading mechanism, and the ability to restore the painting.’” Note that speculative hypotheses are now being presented as sound platforms for restorations. In the art world it is frequently the dogs that don’t bark that matter most. Note that this wonder technique which addresses changes resulting from natural causes would seem to have no powers or potential with regard to the more common and much more seriously deleterious man-made changes made by restorers. Given that both types of injury are easily evident by eye to anyone lifing a picture out of its frame (see Figs. 2 and 3), the silence of “science” on the latter injuries can only seem self-compromising .

In a letter to the Times (February 17) we protested:

“The claim that scientists have recreated the original appearance of a Renoir painting (‘Laser technique shows masterpiece as Renoir intended’, Feb 14) is unfounded. All elements of a picture undergo natural changes over time. To these, further unnatural changes are added by restorers and their invasive paint-penetrating solvents. Compensating for a single faded pigment does not constitute a recovery of a picture’s original appearance. Rather, it offers a further falsification: a single artificially simulated ingredient within a remaining, generally altered and debilitated surviving whole.”

Our letter was accompanied by one from a Professor of Allergy and Clinical Immunology at Imperial College London, making a far-fetched claim that the fact that a synthetic red dye used in paintings had also helped in the discovery of an important white blood cell constituted an unusual “bridging [of] fine art and science”.

While Raman microscopy could certainly disprove the claimed date of the fake Chagall, it seriously misleads the public to present speculative and hypothetical digitally manipulated reconstructions as if literal recoveries of original conditions. On February 22nd the Economist reported an account of another digital re-mastering of real paintings delivered at this year’s meeting of the American Association for the Advancement of Science. The Economist too saw a bridging of the divide between art and science, which it likens to a resolution of the science/art schism of which the chemist and novelist C. P. Snow complained in his famous 1959 lecture “The Two Cultures”. The report also reveals, however, that what was presented as a recovery of the murals’ original conditions was in fact a double hypothetical reconstruction. Not only had Rothko’s colours faded, so too had those of the contemporary photographs of his murals that were to serve as the basis for a digital re-mastering of the actual paintings. Despite the methodologically dubious procedure of digitally re-mastering actual paintings on the back of digitally re-mastered photographs, there was customary breathless admiration for this latest claimed technical miracle:

“In the case of the Holyoke Centre’s Rothkos […e]ach had faded differently, depending on its original colours and how much sunlight it had seen. And various parts of individual paintings had faded at different rates, too. But modern technology allows optical illusions to be finely crafted indeed. The paintings are continuously observed by a high-resolution camera. Its images are compared, pixel by pixel, with the idealised versions provided by the restored photographs. A computer then works out, moment by moment, what mixture of light to shine back to make the faded originals match the vibrant reconstructions—with no messy repainting necessary. For now, the paintings remain under wraps while the museum at which they are stored is renovated. One day soon, though, they will be on display in all their illusory glory.”

There was no discussion of the consequences of viewers’ bodies blocking the projected “correcting” coloured lights. What we are witnessing in this heavily promoted technical bonanza is not a genuinely increased understanding of art by courtesy of scientific advances. If the attempt to increase public understanding of the degree to which even quite modern paintings have suffered alterations since their executions was a real ambition of museum staffs and conservation scientists, it would be imperative for them to discuss (and demonstrate) the largest single source of alterations and adulterations: “restoration” treatments. In the absence of such an agenda, what we see unfolding is a cultually diversionary Big Push by certain professional groups into new and uncontroversial employment pastures where the potential pickings and funding opportunities are immense – there is scarcely an old picture in existence where some pigments have not faded. This virtual remastering show is one that could run and run. But who might fund and who might execute research into all those paintings that suffered far more grievously from the chemical coshes of restorers?

The real problem in the arts is not an insufficiency of technical or scientific assistance. It is deeper and more fundamental. Its root lies within institutional withdrawals from exercising properly critical considerations. The non-appliance of due critical practices is long-standing. There were uncritical responses in the late 1990s when (as we reported in our first post) the National Gallery used a computer-manipulated photograph of an actual skull as the basis for a hypothetical virtual reconstruction of missing parts in Holbein’s “The Ambassadors” which led to the redrawing of Holbein’s skull in defiance (or ignorance) of the perspectival systems of the artist’s times. More recently, the Tate repainted large lost parts of a flood-damaged work on the basis of early colour photographs in the course of a “restoration”. In our uncritical, increasingly “virtual” cultural universe it is more urgent than ever that museum curators should return to acting primarily on sound scholarly appraisals and aesthetically informed insights, and that they should not further devolve their responsibilities to technicians who may or may not be properly alert to matters aesthetic and artistic.

Michael Daley

Comments may be left at: artwatch.uk@gmail.com

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Fig. 1: Above, top, Marc Chagall’s “Reclining Nude 1911” which is said to have been the source for the fake Chagall, “Nude 1909-1910” (above), as reproduced together in the Sunday Telegraph (2 February 2014).
An entire programme in the BBC’s Fake or Fortune series was spent examining the technical composition and the provenance of the fake version (which, incredibly, was dispatched to the Chagall Committee in Paris which not only declared the work a dud but threatens to have it destroyed) when a single glance at the two works should have been sufficient to establish that both cannot be by the same artist. Where that of 1911 displays a boldly deconstructing and reconstructing treatment of forms and spaces that is expansive and pictorially dynamic (as well as being massively indebted to Picasso’s then recent and revolutionary cubist works), the other is manifestly derivative and feebly handled, leaving the picture’s subject looking not so much set in a specially re-ordered non-Euclidian space, as pasted onto a monotonously and repetitively drawn and coloured theatrical back-cloth.
Above, Fig. 2: a detail of a Turner water-colour in the British Museum which had been protected from light damage at the left edge by the frame. (See plate 5 in the “Museum Environment”, 1986, Butterworth-Heinemann.)
Above, Fig. 3: a detail of Frans Hals’ “Banquet of the Officers the St. George militia company”, showing a strip of original green glazing that had been protected from restorers solvents by the frame.
Above, Fig. 4: the much reproduced Renoir, “Madame Léon Clapisson” (here as on the BBC) showing the painting in its present condition at the Chicago Art Institute on the left, and in an attempted digital reconstruction of its original (1883) condition on the right.
Above, Figs. 5, 6 and 7: details, top and centre, of “Madame Léon Clapisson” as found today, showing along the picture’s top edge a surving strip of an originally pink background achieved with a glaze of carmine lake, or cochineal, pigment. Scientists have used the investigative method known as “Surface-Enhanced Raman Spectroscopy (SERS)” in an attempt (above, at Fig. 7) to recreate the picture’s original appearance.
There has been no mention in any reports on this attempted reconstitution of some consideration having been given to changes in the painting that had occurred not as a result of exposure to light but as a result of exposure to restorers’ solvents, swabs and scalpels.
The painting itself and the virtual reconstruction is presently on exhibition at the Chicago Art Institute. The exhibition was supported by research funding provided by the Getty Foundation, the Grainger Foundation, the David and Mary Winton Green Research Fund, the Samuel H. Kress Foundation, and the Andrew W. Mellon Foundation. It is said that with “this new knowledge and new technologies such as nanotechnology, laser light, and advanced image processing software, the conservation department has been able to reconstruct the work’s original colors in a full-scale digital reproduction.”
A PIONEERING DIGITAL ATTEMPT TO RECOVER A PICTURE’S ORIGINAL CONDITION AT THE NATIONAL GALLERY (LONDON)
Above, Fig. 8: The National Gallery’s “The Conversion of the Magdalen” attributed to Pedro Campaña.
Above, Fig. 9: The near contemporary copy of the National Gallery’s “The Conversion of the Magdalen” that was made by Luca Longhi and is presently in the Villa Borghese Collection, Rome.
The National Gallery claims credit for pioneering the new collective discipline known as Technical Art History. A key weapon in its long, proselytizing campaign has been the publication since 1977 of an annual report dedicated to conservation activities – its Technical Bulletin. The issue of 2001 (Vol 22) carried an article “Colour change in The Conversion of the Magdalen attributed to Pedro Campaña” that was jointly authored by Marika Spring, Nicholas Penny, Raymond White and Martin Wyld. Spring and White were members the science department, Penny was a curator, and Wyld was the head of conservation. It was thus a textbook collaborative effort made under the rules of Technical Art History.
The combined expertises were brought to bear on a striking problem with the painting’s physical and optical conditions: there had been severe deteriorations in the colours of many of the draperies, not least in those of Christ. Many draperies were now brown or yellow-brown, where once they had been blue, green or red.
Microscopic samples were taken from some of the figures and analysed in an attempt to identify their pigments and to “investigate whether there was any peculiarity in the technique and the materials that could have caused such serious degradation.” Highly detailed examinations established that the blue pigment – smalt – had deteriorated; that a red lake pigment (likely containing dyestuff from the cochineal insect) had faded; and that green glazes containing copper had turned brown. None of these changes were remarkable in themselves, except, perhaps, in their extent.
What was remarkable was that an attempt was made to reconstruct the “altered colours by digital imaging”. It was explained that the changes which had destroyed the picture’s balance of colours had to be accepted as irreversible. Nonetheless, the attempt was made to gain some impression of the original appearance by manipulating a digital image of the painting – specifically, “by applying image-processing techniques”. Clearly, in such an exercise, the nature and type of image-processing software used would be of crucial methodological significance – how and in what manner was the base digital reproduction of the picture to be manipulated?
Explanation seemed to be to hand in a footnote [27]. Alas, it read flatly as follows: “The technical details of the process of reconstruction of the colours by image processing on the digital image will be described elsewhere.” No less disturbing than having to take the means and manner of the manipulations on trust, the account that followed of the factors of consideration suggested a Technical Art Historical methodology more Heath Robinson Contraption than Hi-Tech Sophistication.
Because the original colours no longer exist on the painting, some simulacrum of each had to be produced to feed into the image-manipulating software. Thus, “colourimetric measurements on painted-out samples matching the pigment mixtures and the layer structures were used as a reference.” Clearly, achieving a reliable point of colour reference was vital to the integrity of the exercise. But how reliable were the painted-out samples? Not very, it seemed on the authors’ own account:
“For the smalt and red lake pigments this posed some problems. Smalt manufactured to a nineteenth-century recipe is available today, but contains a higher percentage of cobalt than than smalt in sixteenth-century paintings and none of the impurities that are commonly found in the glass.” Notwithstanding these departures from the original materials used on the painting, this smalt was used for the base references. Because the modern smalt is much stronger in colour than that of the sixteenth-century, an attempt was made to correct (lessen) its force by adulterating it with “finely ground alumina” in attempt to “to try to simulate the colour of the sixteenth century smalt”. Confidence in this adjustment was not high because “this is a difficult judgement to make, since in paintings of the period smalt has always degraded.” Had the painting been a seventeenth-century work the exercise would have been easier because by then the smalt was commonly mixed with lead white pigment, which afforded some protection. Even though this work was not of the seventeenth-century, samples from that period were used a guide reference in the digital manipulations.
Establishing a reference point for the original lake pigments was no less problematic: “Comparison with the deep shadows on Christ’s red robe, which retain their red colour, made it clear that the hue of the test plate was more purple than the red lake in the painting…” And what of the outcome of this, at best, approximate method?
Above, left, Fig. 10a: the computer-manipulated attempt to recover the original colours of Christ’s draperies.
Above, right, Fig. 10b: a detail of the Borghese Villa copy shown above at Fig. 9.
It probably goes without saying that the figure of Christ seen at Fig. 10a seems a most implausible reconstruction. It is claimed by the authors, however, that: “The deeply saturated colours which replace the deteriorated brown, although rather flat because of the loss of the modelling which cannot be reconstructed, balance well with the well-preserved draperies painted with vermilion and ultramarine.” Given that, on the authors’ own admission, the simulated blues and reds are significantly different and more intense pigments, how credible can this claimed correspondence of colours seem?
The article concludes on an assertive note of self-satisfaction: “The detailed technical examination of the ‘Conversion of the Magdalen’, and the process of reconstruction of the colours in the digital image, has produced some deeper insight into how the deterioration of pigments has affected the colours in the painting.”
This was followed by a claim that is quite remarkably at odds with the visual evidence presented (see Figs. 10a and 10b): “Although the strong and deep colours of the reconstruction initially seemed rather startling, they receive strong support from comparison with the Borghese version of the painting [shown here at Figs. 9 and 10b] – which is especially gratifying since the reconstruction was made before the transparency of the Borghese version was available to us.” Given that the Borghese version is on all accounts markedly better preserved that the London picture, what might explain the former’s richer, warmer red drapery and darker, more sombre blue drapery?
Although the authors express themselves as being satisfied with the accuracy of the reconstructed colours, they do concede other problems: “The reconstruction is not, of course, an accurate portrayal of the original appearance of the painting – the lost modelling in some of the draperies cannot be recreated…”
Thus, we see that this exercise has been directed at a single component part of the painting – its self-contained areas of local colours – and that, in the execution, that part has been wrenched from any relationship with the picture’s tones, shading and modelling. This severance is painfully evident in the comparison at Figs. 10a and 10b. It would beggar belief that the National Gallery’s experts could see any sort of vindication for their efforts in the Borghese version were it not for that institution’s by now too-deeply ingrained to be recognised tradition of pursuing autonomously bright colours during restorations at the expense of form and pictorial coherence. Not only are the colours of the Borghese drapery more sombre and chromatically integrated – and jointly more skilfully integrated with the plastic values – but we see also in the National Gallery picture a characteristic debilitating weakness of modelling in the too-brightly scrubbed surfaces of the flesh areas. (It is depressing beyond belief that our national pictorial vice should recently have crossed the English Channel and now be menacing Leonardos at the Louvre.)
It might be contended that we are not comparing like with like. As the authors point out, the one work is a not an altogether strict copy of the other. Moreover, the Borghese version is acknowledged to be in superior condition: “the better condition of areas painted in red lake in the Borghese painting is strong evidence that it has not been subjected to such harsh environmental conditions as the National Gallery painting…The Borghese picture has spent almost all its life in two collections in the same city, whereas, the National Gallery’s picture has belonged to at least half a dozen collections and has passed on at least three occasions through the art trade, but too little is known about the conservation history of these paintings, and the conditions in which they have been kept, to explain the difference in preservation.” The euphemistic use of the term “environmental” in lieu of “restorational” and the sly allusion to possible bad restoration experiences at the hands of the “art trade” cannot gainsay the fact that there is abundant evidence of works held at and restored within the National Gallery suffering catastrophic losses in the course of a single in-house restoration – as the before restoration (left) and after restoration (right) comparative details of Rubens’ portrait of Susannah Lunden (shown below at Figs. 11a and 11b) testify.
Click on the images above for larger versions. NOTE: zooming requires the Adobe Flash Plug-in.


Discovered Predictions: Secrecy and Unaccountability at the Metropolitan Museum of Art, New York

25th February 2011

Impeccable condition in a painting is more of a goad than a deterrent to restorers. When the youthful Thomas Hoving was appointed director of the Metropolitan Museum in 1967, he formed a respectful – even deferential – alliance with the (then) head of picture conservation, Hubert von Sonnenburg. Two decades earlier in London, the National Gallery’s director, Philip Hendy, forged a similarly dependent relationship with the German émigré restorer Helmut Ruhemann. Ironically, von Sonnenburg had presented as the heir-apparent to Johannes Hell, another German émigré to Britain who’s mild and gradual cleanings were widely preferred to Ruhemann’s controversially swift “total cleanings”.

Hoving and von Sonnenburg together stalked one of Velazquez’s finest portraits, his Juan de Pareja, which the Met acquired in 1970 for a world record $4.5m. Although, on their own testimony, that picture was in superb condition and had never even been lined, on acquisition it was whisked to Wildenstein and Company, “for secrecy”, as Hoving later admitted. There, Von Sonnenburg secretly “proceeded to discover”, as Hoving put it, “everything he had predicted he’d find”.

It was not unprecedented for a museum director to have a major acquisition secretly restored. Sir Charles Eastlake, scorched by National Gallery cleaning controversies in 19th century Britain, had his acquisitions cleaned in Italy before bringing them to the gallery. Secrecy in conservation can seem systemic: in 1960, when the National Gallery constructed “modern” purpose-built conservation studios, part of one was partitioned by a wall, behind which the chief restorer could work on projects of “particular difficulty or confidentiality”, as a then National Gallery restorer, David Bomford, put it in 1978.

Eastlake made no photographic record of the pre-restoration condition of his acquisitions – even though he happily used photographs for attributing paintings, and must, as president of the Royal Photographic Society, have appreciated photography’s unprecedented testimonial capacities. Fortunately, photographic records of the Sonnenburg/Hoving Velazquez restoration were kept and published by the Metropolitan Museum (in an undated booklet – see right). While these photographs may not be of the highest, digital age, standards, they are nevertheless “of a piece” and permit comparisons between recorded states to be drawn.

Much as von Sonnenburg thrilled over an impeccably preserved, never-lined canvas, he could not resist tampering with it. Two of its edges had been folded over on the stretcher. This fact was presented to Hoving as a “discovery”, even though it had been reported by the Velazquez specialist José Lopez-Rey seven years earlier. The folded canvas strips were opened, flattened and reinforced with new canvas to extend the picture’s format and diminish its subject, shifting him leftwards and downwards (see right). The justification for this compositional “recovery” was that original paint had been applied to the folded strips, but the pictorial testimony of that paint, when first revealed, was not photographically disclosed – see account on the right.

Von Sonnenburg, it seemed, could not resist the urge to “liberate” the painting’s supposed “pure flesh tones” and thereby leave the dark-skinned servant’s face lighter and pinker. By stripping off “varnish” von Sonnenburg also caused previously unified components to detach themselves from each other:

the rounded shape of Pareja’s forehead, for example, is defined only by a large spot of impasto-crisp in the center, bordered by dragged spurs – applied directly on the thin underpainting. When seen close up, the highlight seems to be floating over the paint in an almost measurable distance…

This was a classic restoration apologia. Even the emergence of a formerly hidden streak of flesh-coloured paint on the background was presented as an act of liberation and recovery:

Attention should be drawn to the single dragged brushstroke of light skin colour in the center of the background at the right…Unquestionably, this randomly applied paint is original, and shows how Velazquez chose to try out his loaded brush on the background…Such spontaneity, combined with the greatest subtlety of color and technique make the Juan de Pareja one of Velazquez’s most painterly works.

Convinced that Velazquez had happily left his own brush-wipings visible on one of his two finest portraits (the second being his Pope Innocent X), and that he had used glazes less than Titian, von Sonnenburg was not dismayed when his cleaned painting betrayed markedly less colouring and reduced to a “predominantly gray color scheme”. His rationale for losses of colour and of spatial and plastic coherence; for the flattening of a formerly prodigiously well-modelled and sympathetically lit head; and for the spatial inverting of a background that formerly receded, was audaciously lame: in 1938 an English restorer, Horace Buttery, had described the doublet as “dark gray”. Despite recognising that the painting had – miraculously – shown “no signs of ever having been abused by solvent action during the past”, von Sonnenburg nonetheless contended that it must have been cleaned and varnished “at times”. On that basis, he speculated that it could therefore safely be assumed to have been so restored by Buttery, and, therefore, to have enabled him, on that occasion, correctly to have read the doublet’s true colour. This hypothetical daisy-chain was presented as a proof, despite the fact that before and after Mr Buttery, the garment had always been described as a “green doublet” – not least by Velazquez’s biographer, Antonio Palomino who in 1724 precisely reported “a muted green for Juan’s doublet”.

After their stripping and repainting of pictures, restorers invariably apply fresh varnishes… which in turn discolour and thereby serve as a pretext for another “restoration”. With successive varnish removals, solvents deplete, embrittle and optically alter paint films. When penetrated by solvents, paint films heat, swell and soften so that even the friction of cotton wool abrades them – as the restorer Caroline Keck admitted. Soluble plastic components of the paint itself are carried off by evaporating solvents. Restorers sometimes claim that because old paintings have so frequently been abused in the past, there is nothing left to extract today – but with the Juan de Pareja, no such claim could be made. At the same time, they sometimes admit that cleaning pictures with thick paint is easier than cleaning ones with thin paint. (If cleaning methods really were as safe as is claimed, it would not matter whether the paint being treated was thick or thin.) When stripped to a restorer’s conception of “clean”, the remaining paint is left parched, absorbent, matt and in need of “nourishment” by varnishes.

When new varnishes (i.e. resins dissolved in solvents) are applied, they penetrate and amalgamate with the parched paint thereby making the next cleaning the more hazardous, and so on ad infinitum. If we are lucky, von Sonnenburg will have used a natural resin varnish. If not, if he subscribed to the Met’s then hi-tech enthusiasms, he will have used a synthetic resin in the confident but erroneous expectation that it would not discolour and that it would remain easily soluble.

In 1966 a restorer at Moscow’s Pushkin Museum of Fine Arts deplored the use of untested synthetic materials, judging them “all right for space ships” but not for old master paintings. By 1995 a conservation scientist, Tom Learner, reported that synthetic resins which had “appeared to offer” advantages over natural ones “are now known to be inherently unstable”. In 1998 the Met’s (present) Chairman of European Painting, Keith Christiansen, admitted that synthetic varnishes used at the Metropolitan Museum had turned not yellow but grey and had “cross-linked with the pigments below, meaning that removal is, if not impossible, extremely difficult”.

Dr Christiansen has yet to reply to the question ArtWatch and ARIPA put to him on February 6th, concerning the Met’s intentions towards its new, miraculously well-preserved Perino del Vaga painting.

Michael Daley

Comments may be left at: artwatch.uk@gmail.com

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Above, Fig. 1: Velazquez’s oil on canvas portrait Juan de Pareja, before treatment at Wldenstein and Company and when still “covered by a yellowish brown varnish and with the top and right edges folded over” (- as described in an undated, untitled Metropolitan Museum booklet that contained essays by the museum’s President, Douglas Dillon; Director, Thomas Hoving; Vice-Director, Curator-in-Chief, Theodore Rousseau; Curator-in-Charge, European Paintings, Everett Fahy; and Conservator, Hubert von Sonnenburg).
Above, Fig. 2: the Juan de Pareja during treatment when the top and right margins had been unfolded; paint losses had been filled with putty; and new red-brown paint covered some of the fillings and was to serve as a priming for the final “touching up“. At this point, the “discolored varnish” had been removed from the right-hand side of the picture. (This photograph and the one above were by courtesy of Wildenstein and Company.)
Above, Fig. 3: the Juan de Parejaafter cleaning and restoration“. (Photograph was by Taylor & Dull, Inc.)
Above, Fig. 1, detail showing warm orange-red layer over the background and tonal modelling on the lace collar.
Above, Fig. 3, detail showing loss of red on background and the new flattened, whiter-than-white collar.
Above, Fig. 1, detail. Note the relatively small area of lights on the face. Note, too, the large proportion of warm reds and in particular their deployment at all the points at which the forms of the face turn away from the viewer at the profile. At this stage, none of the light passages in the face abutted the black of the hair, the warm red mid-tones formed transitions between the brightest lights and the darkest darks.
Above, Fig. 3, detail. Note, in comparison with the untreated image above it, the profound transformations of pictorial values and language system that occurred as a consequence of this so-called “restoration”. In the post-cleaning and post-restoration state (for both activities took place extensively), the new lighter, cooler background asserts its presence more, in an entirely historically innapropriate modernist, “abstract” fashion. The former, highly selective and focussed placement of the the brightest lights on the collar (which articulated the forms) have been lost in the great expansion of whiteness. The general lightening of the background around the head introduces a halo-effect not previously present. The new light passages to the (viewer’s) left of the hair now nearly meet the lighter passages to the right of the head with most unfortunate and unoriginal consequences. Previously, the head emerged towards the viewer out of a warm dark enclosing space. Now, given the great lightening of the background around the head, the black of the hair can be read as a void in in a light coloured wall. One of the commonest signs of restoration injury to a face is present here: the contrasts between the blacks and the whites of the eyes are intensified regardless of the general system shading that had applied to the head. In the unrestored state, the most brilliant lights present were in the reflected lights of the dark irises, not in the whites of the eyes themselves. Another common loss that is seen here occurs in the tonal modelling around the eyes, which is used to establish the forms of what are essentially a pair of balls set in two sockets. The notorious carelessnes of restorers with anatomical features, is matched by an obvious indifference to shapes. The loss of the coherence of the former treatment of the hair is an almost universal restoration short-coming. Note the extent to which violence has been done to the former linked areas of hair in the subject’s side-burn and beard. Now the lighter mid-tones of the flesh at the cheek race through, breaching the hair like water out of a dam. In order to be complicit with such injuries one would have to subscribe to a fairy tale – one would have to believe that all the previously superior articulations of form, physiognomy, space, atmosphere and pyschological insight, were the unintended, undesigned, fortuitous benefits of some physical degeneration of a layer of varnish. In fact, one would have to subscribe to two fairy tales. One would have to believe that if the present varnish were to be left in place for long enough, it too would improve the drawing and modelling of the present state of the painting; that it would impart red-ness here, and green-ness there to stunning pictorial effect as it gradually turned into a yellowish brown covering.
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How the National Gallery belatedly vindicated the restoration criticisms of Sir Ernst Gombrich

27th January 2011

History has repeatedly shown that scholars and art-lovers (no matter how distinguished and mild-mannered) who put themselves between museum picture restorers and their professional ambitions, run high risks.

In 1950 Ernst Gombrich drew attention, in a Burlington Magazine letter, to Pliny’s description of wondrous effects achieved by Apelles when finishing off his paintings with a thinly spread dark coating or “varnish”. How could we be sure when stripping off “varnishes” today, he asked, that no Renaissance masters had applied toned varnishes to their own works in emulation of antiquity’s fabled painter? He received silence.

When he repeated the question in his seminal 1960 book Art and Illusion, his scholarly reputation and position as director of the Warburg Institute at London University commanded an answer. One came from Helmut Ruhemann, the National Gallery’s consultant restorer and author of its notorious “total cleaning” policy. Ruhemann insisted in the British Journal of Aesthetics that there was no evidence whatsoever “for anything so improbable as that a great old master should cover his picture with a ‘toning-down layer’.”

Gombrich returned play in a 1962 Burlington Magazine article (“Dark varnishes: Variations on a Theme from Pliny”). The discovery of a single instance of a tinted overall varnish, he suggested, would undermine the dogmatic philosophy of the National Gallery’s restorers. A dual reply came from the gallery’s “heavy mob” – its head of science, Joyce Plesters (who was married to the restorer Norman Brommelle), and the pugnacious former trustee and collector, Denis Mahon, in two further Burlington articles.

Plesters herself dismissed Gombrich on two fronts: for lacking “technical knowledge” and for displaying incomplete and misinterpreted scholarship. The entire documented technical history of art, she claimed, showed that “no convincing case” could be made for a single artist ever having emulated Apelles’ legendary dark varnishes. The passage from Pliny, she sniffed, was merely a matter of “academic rather than practical importance”. She offered to “sift” and “throw light upon” any future historical material that Professor Gombrich might uncover – should he but present it directly to the National Gallery. Her technical rank-pulling was underwritten (as perhaps was her article in part) by the director, Sir Philip Hendy, who disparaged technically ignorant “university art historians” in the gallery’s annual report.

In reality Plesters was a technical incompetent. It was she who claimed that the Raphael cartoons at the Victoria and Albert Museum were stuck onto “backing sheets” when there are none. It was she who described the large (150 cms wide) panel The Entombment, which is attributed to Michelangelo, as a single massive plank when it is comprised of three boards held by butterfly keys. It was she who counted six boards on the large panel Samson and Delilah, which is attributed to Rubens, when there are seven.

Her errors were products of a then unchecked institutional culture of technical adventurism and gross aesthetic recklessness. Great Renaissance paintings were ironed onto boards of compressed paper (Sundeala board) which today are too unstable to be moved. One such was Sebastiano del Piombo’s The Raising of Lazarus. That painting, originally on panel, had been transferred to canvas. When decision was made to re-attach the canvas to a Sundeala “panel”, technical examination identified three further “backing” canvases. When these three “backings” were duly removed it was discovered that no fourth and “original” canvas existed and that the surviving paint was attached only to a layer of disintegrating paper. But that crisis-of-their-own-making provided the gallery’s restorers with opportunity to play what Professor Thomas Molnar here called “demiurge” and improve upon the artistic content of the painting. In order to stabilise the paint layer which they had left loose and unprotected, the restorers embedded it from behind with terylene fabric attached by lashings of warm, dilute wax-resin cement. Because Sebastiano had painted his picture on a warm-coloured ground and because paint becomes more translucent with age and allows the tone of the ground greater influence on the picture’s values, the restorers decided to brighten things up and give the picture a brilliant white ground (like that of a Pre-Raphaelite painting) by adding highly reflective pigments to their own remedial wax-resin cement applications.

Plesters died in August 1996. Earlier that year, the National Gallery had published a report in its Technical Bulletin on the cleaning of two paintings by a Leonardo follower, Giampietrino. One, his Salome, had clearly suffered the Gallery’s trademark restoration losses of modelled form (see right and below), but his Christ Carrying the Cross was miraculously unscathed. Moreover, that picture was found simultaneously to display an “intensity of colour” and a restrained “overall effect” – precisely the paradoxical combination attributed by Pliny to Apelles but that had been pronounced technically preposterous by Ruhemann, Plesters, Mahon, Hendy et al.

It further emerged that Giampietrino, having first built up an “illusion of relief” with “dark translucent glazes”, had, again just as Pliny had said of Apelles, deliberately “restricted his own range of values” with a “final extremely thin overall toning layer consisting of warm dark pigments and black in a medium essentially of walnut oil, with a little resin”. Sir Ernst, nearly half a century on, had finally been vindicated but the report, inexplicably, made no reference to the dispute of the 1960s – to the very dispute which in 1985 had been described by the Burlington Magazine’s then editor, Neil MacGregor, as “one of the most celebrated jousts” ever. Had the National Gallery, having ridiculed Gombrich in the 1960s, not told him of its own remarkable technical/art historical discovery and of his own vindication? It had not. When we reported the findings in June 1996, Sir Ernst was approaching his 87th birthday. He replied:

I could hardly have a nicer present than the information you sent me. I don’t see the National Gallery’s Technical Bulletin, and would have missed their final conversion to an obvious truth…

Gombrich’s vindication proved a double one. Not only had the gallery discovered a technical/physical corroboration of the scholar’s astute original supposition, but the survival of a Renaissance artist’s final toned coating served further to corroborate Gombrich’s general criticisms of the gallery’s over-zealous picture cleanings. Because the two Giampietrino works were restored at the same time in the same gallery, but with the surface of the one being protected from solvent action by an ancient oil-film, while that of the other was unprotected, an unwitting laboratory experiment had been conducted on the gallery’s own “cleanings”. We can now compare the appearance of the restored but protected painting, with that of the restored but unprotected one (see right and Michael Daley, “The Lost Art of Picture Conservation”, The Art Review, September, 1999). As can be seen here, the unprotected painting (the Salome) suffered clear and dramatic losses of modelling and weakening of forms.

For a number of years after the twin Giampietrino restorations, it was possible to examine the two cleaned specimens side by side and to demonstrate the unequal effects of the treatments they had received. That is no longer possible. One of the pair has been relegated to the ill-lit basement of the reserve collection which is accessible to the public for only a few hours a week on Wednesday afternoons.

The relegated work is not the restoration-injured Salome, but the miraculously preserved Christ, the very picture which now arguably constitutes the best-preserved example of a Renaissance artist’s technique in the entire collection. This picture, which might be expected to enjoy pride of place in the main galleries, shares its new dungeon exile with another recent National Gallery Embarrassment – the Beccafumi panel painting Marcia which was dropped and smashed at the Gallery when being “de-installed” from a temporary exhibition. We had hoped and suggested that the Christ might make a return to daylight on the occasion of the Gallery’s forthcoming Leonardo blockbuster exhibition, but it seems that it will not do so – not even to join Giampietrino’s full-sized faithful copy of Leonardo’s Last Supper. (For many years, that Giampietrino mouldered in the Royal Academy’s basement as embarrassing relic of the institution’s former artistic interests.) When the last restoration of Leonardo’s Last Supper got into difficulties, the copy was taken to Milan so that full-size tracings of Leonardo’s figures might establish the limits of the restorer’s own substantial watercolour in-painting.

It seems fitting that last word be given to Sir Ernst, who died on November 3rd 2001. In another letter in 1988 he had recalled:

I believe it was Francis Bacon who said ‘knowledge is power’. I had to learn the hard way that power can also masquerade as knowledge, and since there are very few people able to judge these issues, they very easily get away with it.

Michael Daley

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Sir Ernst (Hans Josef) Gombrich OM, CBE.
Born March 30th 1909, died November 3rd 2001
Above, Giampietrino, Christ carrying his Cross (NG 3097), c. 1510-30, Poplar, 59.7 X 47 cm.
Below, Giampietrino, Salome (NG 3930), c. 1510-30. Poplar, 68.6 X 57.2 cm.
Above, Giampietrino, Crist carrying his Cross, detail.
Below, Giampietrino, Salome, detail.
Below, Giampietrino’s Salome, before cleaning (left), after cleaning (right). Note the equalization of the shading tone on the drapery over the arm to the left that is seen in the cleaned state of the picture on the right. Note also, the weakening of the shading and modelling on Salome’s head and the weakened necklace (as was also seen in the Vermeer portrait of a girl in the post of January 23rd).
The black and white photographs above and below constitute proofs of artistic injury. This can be said with confidence for two reasons. The extent and the progressively graduated manner of tonal variations seen along the successive folds of the drapery (before cleaning) are manifestly aristically informed and plastically purposive. It is inconceivable that accumulations of what restorers fondly call “filth”, or the natural discolorations of an ageing varnish film, could produce so skillfully orchestrated and enhancing complement to the linear design of the drapery. Artistically “formal” considerations apart, those – now gravely weakened – tonal gradations formerly served clear “theatrical”, symbolic and moral purposes. The light source within the picture falls from top left to bottom right. Salome, as if in shame or remorse, averting her eyes from her own dark deed, turned away from the Baptist’s severed head towards the light. The profiled side of her face, her neck and shoulder, and the drapery over her shoulder caught the light. The rest of the figure and drapery progressively descended into the central gloom of the painting. Such manipulations of contrasting values, which give expression to the principle player’s distressed ambivalance, are products of artistry and artistry alone. They are never fortuitous by-products of any natural disintegration of materials or accumulations of extraneous matter.
Photographs by courtesy of the National Gallery.
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