The controversy regarded the conservation of oil paintings, and especially the different methodologies, practical and theoretical, on how to approach the cleaning of pictures.
The characters involved were of the highest calibre: the National Gallery in London, the Istituto Centrale per il Restauro (I.C.R.) in Rome and Ernst Gombrich, who in 1959 had been appointed Director of the Warburg Institute.
Between 1936 and 1946 a large number of National Gallery paintings were cleaned by nine different restores, among whom the best known was Helmut Ruhemann. Over seventy newly-cleaned paintings, among which Titian’s Bacchus and Ariadne (illustrated here), were included in the 1947 National Gallery exhibition, simply titled Cleaned Pictures.
The accompanying exhibition catalogue addressed many of the controversial issues surrounding conservation. For instance, the National Gallery Director at the time, Philip Hendy, stated in the catalogue introduction: ‘However safe the method, however correct the principle, there will still be a margin for legitimate discussion concerning the finished product. Much of the criticism comes from those who best know and most love the pictures, in the ownership of which they have a share. Their criticism may help those who are responsible never to forget the extent of their responsibilities and to be always examining their principles and methods.’
However, the exhibition did not allay public criticism and consequently a Standing Committee of Enquiry (known as the Weaver Committee) was appointed to investigate the Gallery’s conservation work. The Weaver Committee Report stressed the importance of a scientific approach to conservation, and led to the establishment of a Chemical Laboratory, staffed by a Chemist and a Scientific Assistant. The in-house Conservation Department had already been established in 1946, consisting of a Consultant Restorer [Helmut Ruhemann], a Restorer and a Craftsman.
The Weaver Report concluded that no damage was found to have resulted from the recent cleaning.
The opinion of the Weaver Report was not shared by all. In 1949 the Italian restorer Cesare Brandi wrote a heated article in the Burlington Magazine, explaining concepts such as patina, varnish and glazes, which, he believed, needed careful methods of conservation and preservation.  Brandi was vehemently against the cleaning methods employed by the National Gallery. Brandi claimed that in the past artists applied all sort of finishes – varnishes and glazes – to temper the vivid tints of their works. These resulted in a softening, darker effect, known as patina. Brandi believed that leaving the pictures with their patina was closer to the artist’s original intention. Brandi stated that ‘the last refugee of the upholders of total cleaning is the hypothesis that dirt, varnishes accumulated over the centuries and so forth, are being palmed off as patina.’ He explained that what today was called patina, was nothing more than glazes or tinted varnished, and he stated that to remove those would mean remove a significant part of the painting.
Following Brandi’s article, the Burlington published a reply from Neil Maclaren (Deputy Keeper) and Anthony Werner (Research Chemist) at the National Gallery. Maclaren and Werner admitted that the controversy had some beneficial effects on the investigation of the problems surrounding conservation methods but they, understandably, defended the National Gallery’s modus operandi. They opined that paintings had gone under restoration and cleaning since the antiquity, and many of them did not carry anymore the original glaze or varnish. They emphasized that the early cleanings ruined the paintings, but not the latest.
The debate was then based largely on disagreements on terminology and technical procedures, but the Burlington had claimed that ‘taste’ and ways of seeing permeated the debate already since its 1947 Editorial. This aspect took further momentum in the early 1960s, when in February 1962 a Burlington article, ‘Dark Varnishes: Variations on a Theme from Pliny’, was written by Ernst Gombrich. The focus of the dispute shifted then on aesthetical considerations supported by primary evidence. In fact, Gombrich approached the controversy using Classical sources. He referred to the Roman philosopher Pliny the Elder and his writings about Apelles’ painting techniques in the Naturalis Historia.
Gombrich reported this passage from Pliny as witness for the existence of opaque glazes: ‘He [Apelles] used to give his pictures when finished a dark coating so thinly spread that, by reflecting, it enhanced the brilliance of the colour while, at the same time, it afforded protection from dust and dirt and was not itself visible except at close quarters.one main purpose was to prevent the brilliance of the colours from offending the eye, since it gave the impression as if the beholder were seeing them through a window of talc, so that he gave from a distance an imperceptible touch of severity to excessively rich colours.’ 
In his 1960 book Art and Illusion, Gombrich had already written about the cleaning controversy in the chapter about light and visual attitude. There he opined that the need for brighter colours on old master paintings is mainly due to our culture’s aesthetics, especially after the success and dissemination of Impressionist painting.
Put it in simple words, we now like brighter colours.
In his Burlington article of February 1962, Gombrich asserted that assuming that all the finest painters used a glaze as a finish it would be wrong, if not in very few occasions such as to ‘remedy some accidental mishap’ to remove it.  He also underlined that there was a vast contingent of artists, art historians and art professionals who disagreed with the National Gallery’s restorations. In fact, he stated severely that ‘Surely when many independent observers agree that certain paintings now look stripped, harsh or incoherent after ‘cleaning’ it is not sufficient to reply or imply that since none of the original pigments can be shown to have been removed these critics must obviously be enamoured of dirt.’ Gombrich then criticised the governmental ‘committee culture’ and added that ‘Official bias will always favour ‘objective’ rules of procedure which exempt the restorer and his employers from the responsibility of agonizing decisions.’
In the same issue of the Burlington, Otto Kurz, then Librarian of the Warburg Institute, followed the lead of Gombrich in his article ‘Varnishes, Tinted Varnished, and Patina’. Kurz analysed theoretically the differences between varnishes and tinted varnishes, through the documents, notes and recipes left by the artists. 
In his last article about the Cleaning Controversy, Controversial Methods and Methods of Controversy, published in the Burlington in March 1963, Gombrich, perhaps in a desire of finding some reconciliation, stated the importance of scientific analysis, and he wrote: ‘I hope I do not underrate the importance of scientific evidence for understanding of painting techniques and the problem of restauration.’ Nevertheless, in an official Report of the National Gallery, it was stated that his intervention fomented the controversy.
In this controversy there were two opposite methods of dealing with historical objects, and with history at large.
On one side the neo-positivist, scientific-based approach by Ruhemann and the National Gallery that believed optimistically that 1960s conservation experts could help restore Titian’s original brilliance. For this faction, history is a measurable, approachable continuum and we can, with our present knowledge, relate to the past directly and even ‘improve’ on it.
On the other side, the Warburg scholars that deferred authority to the document and felt that there is such a distance between us and the past, such a difference in technical methods and ways of looking and thinking that sometimes the only possible intervention is an informed lack of intervention. This is a position theoretically similar to Gadamer’s view of history as expressed in his 1960 book, Truth and Method.
These differences are ultimately irreconciliable.
What was the role of the Burlington itself in this controversy? Since the 1940s the Magazine had expressed concerns on these cleaning policies, and in fact the Burlington gave the initial voice to those who were against the National Gallery’s methods: Brandi, Gombrich and Kurz. But the fact that an equal space was given in its pages to both sides of the controversy shows that the Burlington approached this controversy with the usual intellectual rigour and wished for both aspects of the debate to be thoroughly investigated and discussed.
The position of the Magazine was borne out of was concerns about the ‘over-cleaned’ paintings rather than from the desire to bring on a sensationalist attack at the National Gallery. In fact, the Magazine has been closely connected to this institution at every time of its existence and the two had a shared past and present. For instance, there has often been a exchange of staff (and contributions to joint projects) between Editors and writers of the Burlington and National Gallery professionals – just to name two illustrious examples, CJ Holmes and Neil MacGregor have been both National Gallery Directors and Burlington Editors.
The controversy had positive effects. For instance, it caused a leap of improvements to the study of conservation and cleaning. The Weaver Committee opened the new era of in situ conservation studios. Brandi published in 1963 La Teoria del Restauro (The Theory of Restauration) a landmark theoretical essay of restauration, where he underlined, as mandatory, the sharing among experts and scholars of conservation methodologies.
BP and GDR, July 2015
Titian, Bacchus and Ariadne, 1520-1523, London, The National Gallery
Paul Joyce, Sir Ernst Hans Josef Gombrich, 1975, London National Portrait Gallery
- Brandi, Cesare: ‘The Cleaning of the Pictures in Relation to Patina, Varnish, and Glazes’, The Burlington Magazine, July 1949 (article)
- Maclaren, Neil, and Werner, Anthony: ‘Some Factual Observations about Varnishes and Glazes’, The Burlington Magazine, July 1950 (article)
- Brandi, Cesare, and Gombrich, Ernst: ‘The Cleaning of Pictures in Relation to Patina, Varnishes, and Glazes’, The Burlington Magazine, Oct. 1950 (letters)
- [Anonymous]: ‘The National Gallery Cleaning Controversy’, The Burlington Magazine, Feb. 1962. (editorial)
- Gombrich, Ernst: ‘Dark Varnishes: Variations on a Theme from Pliny’, The Burlington Magazine, Feb. 1962 (article)
- Kurz, Otto: ‘Varnishes, Tinted Varnishes, and Patina’, The Burlington Magazine, Feb. 1962 (article)
- Clark, Anthony M., Coburn Withrop, J., and Gombrich, Ernest. The National Gallery Cleaning Controversy. The Burlington Magazine. June 1962 (letters)
- Plesters, Joyce. Dark Varnishes – Some Further Comments. The Burlington Magazine. London. Nov. 1962 (article)
- Mahon, Denis. Miscellanea for the Cleaning Controversy. The Burlington Magazine. London. Nov. 1962 (article)
- Rees Jones, S. The Cleaning Controversy: Further Comments. The Burlington Magazine. London. March 1963 (article)
- Gombrich, Ernest. Controversial Methods and Methods of Controversy. The Burlington Magazine. London. March 1963 (article)
- Gombrich, Ernest. The National Gallery Cleaning Controversy. The Burlington Magazine. London. July 1963 (letter)
- Mahon, Denis, and Gombrich, Ernest. The National Gallery Controversy. The Burlington Magazine. London. Sept. 1963 (Shorter Notice)
- Koler Manfred. Surface Cleaning and Conservation. The Getty Conservation Institute.
- Restauration versus Conservation. The National Gallery
- Bomford, David. The Consevation Department of the National Gallery. National Gallery Technical Bulletin Volume 2. 1978
 For Helmut Ruhemann (1891-1973), see: http://www.hki.fitzmuseum.cam.ac.uk/archives/helmutruheman
 Hendy, Philip. An Exhibition of Cleaned Pictures. London. 1947. P.XXIV.
 Brandi, Cesare. The Cleaning of Pictures in Relation to Patina, Varnish, and Glazes. The Burlington Magazine, July 1949, p.183-188. Cesare Brandi (1906-1988), a specialist in conservation and restoration theory, was the first director of the Istituto Centrale per il Restauro (I.C.R.) in Rome.
 Maclaren, Neil and Werner, Anthony. Some Factual Observations about Varnishes and Glazes. The Burlington Magazine, July 1950. P.189-192.
Inventa eius et ceteris profuere in arte; unum imitari nemo potuit, quod absoluta opera atramento inlinebat ita tenui, ut id ipsum, cum repercussum claritates colorum omnium excitaret custodiretque a pulvere et sordibus, ad manum intuenti demum appareret, sed et luminum ratione magna, ne claritas colorum aciem offenderet veluti per lapidem specularem intuentibus et e longinquo eadem res nimis floridis coloribus austeritatem occulte daret. Pliny, Hist. Nat. XXXV, 97.
 Editorial, The National Gallery Cleaning Controversy. The Burlington Magazine. Feb. 1962. P.49-50.
 Gombrich, Ernst. Art and Illusion. New York and London. 1960. P.60-72.
 Gombrich, Ernst. Dark Varnishes: Variations on a Theme from Pliny. The Burlington Magazine. Feb. 1962. P.51-55.
 Kurz, Otto. Varnishes, Tinted Varnished, and Patina. The Burlington Magazine. Feb. 1962. P56-59.
 Gombrich, Ernst. Controversial Methods and Methods of Controversy. The Burlington Magazine. March 1963. P.90-93