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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

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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.”
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

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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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