Uncovering vibrant colours through cleaning

Virgin and Child by Jos van Cleve is an oil painting on a wood panel that belongs to the Fitzwilliam Museum, Cambridge. The work was recently restored in preparation for the upcoming exhibition Madonnas and Miracles. The painting was in excellent condition prior to the conservation treatment, apart from a discoloured varnish that obscured the surface and dulled the vibrant colours used by the artist.

The Artist

Joos van Cleve (1464-1540) was a German-born painter active in Antwerp during the first half of the 16th century. His style can be described as a mixture of traditional Flemish and Italian Renaissance techniques. This particular painting, created between 1525-1529, is a good example of his hybrid style, as the traditional Flemish paint build-up and landscape contrasts with the Virgin’s sfumato shadows copied from paintings by Leonardo da Vinci. The subject of the Virgin and Child was very popular during this period and numerous versions of this composition exist by Joos van Cleve and his studio. The Fitzwilliam version has a peculiar detail, namely that the Virgin is smiling and her teeth are visible between her lips; a feature not usually seen in other representations of the subject.

 (click to enlarge photos)

The painting: construction and layers

The wooden support consists of two oak boards, quarter sawn and butt-joined using animal glue. The boards have not separated since the panel’s creation,  demonstrating the high quality of the wood and the expertise of the panel makers. We know that the panel had an original engaged frame, since a raised edge or ‘barb’ can be seen along the edge of the white chalk ground. This indicates that the panel was inserted into a frame immediately after its construction. Following this, the ground layer would have been added to the panel and the front of the frame simultaneously, leaving a build-up of ground along the inside of the frame.

A Flemish panel painting of this period would typically have been sized with a layer of animal glue on both sides, in order to limit the hygroscopic response of the wood. Following this, a ground layer would have been applied to the front of the panel in 1-2 layers and sanded to obtain a smooth finish. Northern grounds from the 15th-16th centuries are characterised by their use of animal glue and chalk (calcium carbonate), in contrast to the gypsum (calcium sulphate) grounds used by Italian artists during this period. The preparation of the ground was most likely carried out by professional panel makers, as opposed to the artist’s own workshop. Upon receiving the prepared panel, the artist would start by isolating the ground with a layer of oil (usually linseed or walnut). An initial design of the composition would then be drawn on top of the ground using a dry medium such as charcoal, pencil or chalk. In other cases wet media such as ink or diluted paint were used.

These preparatory designs or ‘underdrawings’ are often obscured entirely by subsequent applications of paint and are therefore invisible to the naked eye. However, the carbon content of traditional underdrawing media ensures that  they can be seen using infrared reflectography; an imaging technique that makes use of the longer wavelengths of infrared radiation to penetrate the upper paint layers and reveal the drawing below (Fig.). This method was used to uncover the detailed underdrawing used for the Fitzwilliam painting. Through scrutinising the intricate draughtsmanship that provided the basis for the composition Joos van Cleve’s mastery is fully revealed. A variety of lines were used to create an initial sketch for the composition, ranging from the curved outlines of the infant Christ’s flesh to the more angular and hatched marks used to indicate the folds of the Virgin’s robe.  In contrast to the detailed design reserved for the figures and drapery, there appears to be no underdrawing present for the landscape. It is possible Joos van Cleve had an apprentice in his workshop who filled in this part of the composition without the use of a preparatory design, as it was common to have students and trainees specialise in painting various parts of the painting.

Once the underdrawing was complete the paint was applied using very thin layers. The darker passages of the painting consist of several transparent layers painted on top of each other to give depth, exemplified by the folds of the Virgin’s robe and the darker tones of the landscape. Finally, the painting would have been finished through the application of a varnish, which most likely consisted of a natural resin dissolved in spirit or cooked in oil. The purpose of a varnish is to saturate the colours within the painting, creating a sense of depth, whilst also harmonising the various tones throughout the composition.

Conservation treatment

The initial treatment step consisted of surface cleaning to remove the thin layer of dust and grime that had accumulated on the painting’s surface over time. The varnish was then removed using organic solvents, which were chosen based on previous cleaning tests. The yellowed appearance of the varnish had a flattening effect on the shapes within the composition,  whilst also dulling the vibrancy of the colours. The removal of the varnish revealed a significant visual improvement for the painting. However, this was only the beginning. Underneath the varnish a grey layer of dirt continued to obscure the colours within the composition and its removal brought even more luminosity to the surface of the painting. In addition, a campaign of overpaint covered passages of old abrasions and losses, most notably in the red cloak of the Virgin and the tree on the right-hand side of the painting (these passages of overpaint are marked using red in the lower right photograph).

After the removal of the final dirt layer a very old, degraded layer of varnish remained on the cloth of honour behind the Virgin. It is possible that this localised coating was left by a previous restorer, perhaps due to the sensitivity of the paint in this area to organic solvents. The cloth, originally blue, had acquired a brownish-grey tint. Microscopic samples were taken from the painting to establish whether this layer was original or not. Examination of the samples in cross section indicated that the grey layer consisted of an old, oxidised varnish, as opposed to a pigment-containing glaze. The cross section samples further showed that the layer underneath contained blue and red pigment particles, creating an optical purple colour (see below). However, after cleaning the colour revealed showed a slightly more blue hue, most likely due to the photo-degradation and resultant fading of the organic red lake used for the optical mixture. 

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Sample from the cloth of honour, normal light (©Polkownik)
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Sample from the cloth of honour, ultraviolet light (©Polkownik)

Once it was clear that the uppermost degraded varnish layer was not pigmented, and therefore not considered original, we proceeded with the removal of this layer. The picture below shows the right side of the cloth after cleaning, revealing a vibrant purplish blue, while the left side is still covered by the discoloured varnish.

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Fig. During cleaning, the right half of the cloth of honour has been cleaned (© Polkownik)

After the cleaning was complete, the painting was re-varnished using a modern synthetic resin that will not yellow upon ageing. The losses were filled using a water-soluble putty consisting of gelatin and chalk, and the fills were retouched using synthetic resin and pigments. All of the phases of the restoration, including varnish, fills and retouching are designed to be completely reversible, to facilitate their easy removal in the future. 

(Click to enlarge photos)

Although this painting came to the Hamilton Kerr Institute for minor restoration in preparation for an exhibition, the treatment served the purpose of uncovering the hidden  brightness of the colours, whilst also bringing forth the previously flattened volumes and shapes within the composition, most notably in the delicate sfumato of the Virgin’s face. The opportunity to restore such a beautiful and exceptionally well preserved painting was extremely enjoyable, whilst observing the mastery of Joos van Cleve in such detail helped broaden my understanding of 15th century Flemish painting technique.

Camille Polkownik – 2nd year Post Graduate Intern (2015-2017)

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The Madonnas and Miracles exhibition (video)


About the Author

Ms Camille Polkownik graduated with a Master’s Degree in the Conservation and Restoration of Paintings in 2014, from the École nationale supérieure des arts visuels de La Cambre in Brussels (Belgium). She also has a Bachelor degree in the Conservation and Restoration of Painted Works (2011) from the Superior School of Fine Arts, in Avignon (France). She has interned in the Royal Institute for Cultural Heritage (KIK-IRPA, Belgium), the Royal Museums of Fine Art of Brussels (Belgium), the Museum of Fine Arts in Nice (France), at the Art Gallery of New South Wales (Sydney, Australia) and in private studios.

Her current research projects include the study of extenders added to Prussian Blue from 18th to 20th century in Europe, while matching and comparing paint samples to historic sources, and the characterisation of an unusual form of lead white called “Prismatic Lead White”.

To contact Camille Polkownik: camille.polkownik@gmail.com

Sir Alfred East RA – Late 19th Century Landscape Painter

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Self Portrait (©Kettering Art Gallery)

It is without a doubt that the artist Sir Alfred East (1844-1913), who was inspired by the Barbizon School, enjoyed the interest of the 19th century public.[1] The Times, for instance, referred to him on more than 500 occasions, and printed 11 bulletins describing his fluctuating condition in the month before he died.[2] Amongst various honours on a national and international scale bestowed on him, he was elected president of the Royal Society of British Artists (a post he held from 1906 until his death), received the status of Royal Academician (1913) and was awarded a knighthood by Edward VII (1910), but has since regrettably fallen into obscurity. Despite a slow start to his career, he was commissioned by the Fine Arts Society, to record the landscape of Japan over the course of a year. Subsequent travels he embarked on throughout his career to Europe and America yielded a vast collection of drawings, etchings and paintings in oil and watercolour. Before his death in 1913 East initiated the construction of the Alfred East Art Gallery in Kettering, Northamptonshire, that received a generous amount of his works.

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Lake Bourget from Mont Revard, France (255 x 204 cm) before treatment, normal light (©Titmus)
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Midland Meadows (162 x 218 cm) before treatment, normal light (©Titmus)

It is from this gallery that two of his paintings, namely Midland Meadows and Lake Bourget from Mont Revard, France, arrived to the Hamilton Kerr Institute for conservation treatment. The discoloured and disfiguring varnish layer on both paintings, was identified  as the main reason for the conservation treatment, although structurally sound, standing as a testament to his sound painting technique. Before the treatment of any painting, it is useful to conduct research about the artist and his painting technique, since it can often give an indication of the materials used by the artist. Nineteenth-century paintings in particular, frequently exhibit experimentation with media and layering that might give an unexpected and inconsistent response to the commonly used solvents for cleaning. Fortunately, in this case, the artist himself was rather keen on sharing his skill of landscape painting and how ‘to get the spirit of’ nature captured in a picture. [3] East wrote and published The Art of Landscape Painting in Oil Colour, his own guide to landscape painting, in 1906.[4] This manual explains his painting technique, and even mentions the pigments found on his palette, including the exact tube sizes. Thus it unsurprisingly formed an invaluable source for the treatment of the paintings.  

From his writings it appears that he adopted a well established three-stage-technique that makes use of an under-painting, another layer concerned with the correction of values, and a final stage for the addition of details; all painted with lean oil paint. During this process he practically repainted the entire canvas after the first layer and then proceeded to pick out isolated sections that required further reworking and detail. In doing so, some parts of the second layer that were not reworked in the last stage, and are now part of what is visible in the version we see today. An example of such an area is the fold over edge of Midland Meadows that shows trees reaching higher in the previous layer.

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Midland Meadows, detail of first painting stage, normal light (©Straub)

Between the individual layers, East added medium (or binder) to saturate his lean oil paint layers – a process also known as ‘oiling out’. [5] Favoured particularly in the 19th century, this method used a cloth dipped in a medium of choice (- poppy seed oil for East), and rubbed into the dried paint, before the next paint layer followed. Some cross sections of the painting appear to show a layer that might be identified as such, with a characteristic absence of pigment and ultraviolet light quenching that is to be expected (not pictured in this article).  

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Lake Bourget left: at the Royal Academy exhibition in 1900; middle: published in East’s The Art of Landscape Painting in Oil Colour in 1906; right: the painting in today’s state in ultra violet light (©Straub)

Not only is it possible to see proof of East’s described painting technique in his paintings, but Lake Bourget also reveals a significant compositional change by the artist that must have happened more than six years after it was first exhibited in 1900. Since the painting did not sell during the Royal Academy Exhibition, East may have been inclined to rethink his composition after a critic of his painting found that ‘his trees have had so much of the reality abstracted out of them that they cease to be interesting.’[6] An image of the same painting published in his manual in 1906 shows no changes. The first instance of alterations was registered by the Alfred East Art Gallery in Kettering who received the painting directly from the artist for their opening exhibition in 1913. There is little doubt that East’s reworkings happened before the painting arrived to the Gallery. In ultraviolet light it is also possible to ascertain some of the less visible passages he revisited, since they lie above the oiling out layer and therefore appear darker.

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Lake Bourget, sensitive areas marked in yellow, normal light (©Titmus, Straub)

These areas also directly correspond to the passages that exhibited solvent sensitivity during cleaning. East’s described use of lean oil paint suggests that his mixtures were under-bound, meaning the pigment particles were not sufficiently coated with binding medium and therefore friable. Consequently the varnish covering sensitive areas was merely reduced and a thin layer was left in place.

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Midland Meadows, during cleaning, normal light (©Straub)
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Lake Bourget, during cleaning, normal light (©Straub)
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Lake Bourget, detail varnish drip marks, normal light (©Straub)

After surface cleaning the decision to remove the discoloured varnish layer was supported by the fact that it reached into ageing cracks and losses, which means it is less likely that it was applied by the artist. Visually this layer also distracted from the composition with its drip marks in the sky.  In order to remove the varnish, small test areas in different coloured passages, were opened up to establish the best mixture of solvents for cleaning without affecting the paint layers. Usually the sensitivity of a paint layer corresponds to a specific colour or medium used in a passage. However, this was not the case in East’s paintings since the solubility appeared to be caused by underbound final paint dabs of varying colour. After cleaning an isolating synthetic resin varnish was applied, which is less prone to yellowing in the future than its natural counterpart, and the few existing minor losses were filled and retouched. To protect the paintings from vibration and environmental influences a sailcloth stretcher-bar-lining was attached. Moving and lifting such a large scale object, required continuous help from everyone in the studio, and framing was no exception to this. The gilt frame was given a few alterations to house the painting more securely (see the Weston Park in-situ post for more information) before the painting and frame were wrapped and transported back to the Alfred East Art Gallery in Kettering.

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Midland Meadows, after treatment, normal light (©Titmus)
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Lake Bourget from Mont Revard, France, after treatment, normal light ‎(©Titmus)

During the research for this project it was also possible to catch a glimpse of East’s meticulous character from his artist supplier account with Charles Roberson & Co, a 19th century colourman whose archive is housed at the Hamilton Kerr Institute. When he was sent a selection of brushes from Roberson, East rejected the majority; perhaps because they didn’t meet his standard.[7] He also appears to have repeatedly bought similar items from Roberson, suggesting that he may have had several specific colourman for different types of supplies.

Spending long hours in front of a painting the colours, lines and brushstrokes of the artist become very familiar. This direct contact with the painting was only furthered by the information that was gained about this artist and his technique, and made the treatment all the more interesting. Do visit the Alfred East Art Gallery in Kettering to see the actual paintings in their original exhibition space (due to their changing exhibitions it is best to inquire before a visit if the paintings are currently on display).

Michaela Straub, 3rd year Student

Bibliography

[1]https://books.google.co.uk/books?id=05C02RhJZCkC&pg=PA360&lpg=PA360&dq=alfred+east+benezit&source=bl&ots=QKqmf09Oc5&sig=VU5GADli_TXiXvMjTq44kEfW0_A&hl=en&sa=X&ved=0ahUKEwjZ9eCVx5vQAhWsB8AKHTUqDv0Q6AEIQTAK#v=onepage&q=alfred%20east%20benezit&f=false and https://en.wikipedia.org/wiki/Alfred_East

[2]J Paul & M Kenneth, Alfred East Lyrical Landscape Painter, Bristol, 2009.

[3] J Paul & M Kenneth, p. 25.

[4] A East, The Art of Landscape Painting in Oil Colour, London, 1906. Further publications after his death include: E Bale & A East, Brush and Pencil Notes in Lanscape, London, 1914.; A East, H Cortazzi & Japan Society (London), A British Artist in Meiji Japan, Brighton, 1991.

[5] Oiling out is mentioned by several other artists such as George Frederic Watts in Watts, M. S. 1912. George Frederick Watts, London;  Gilman Harold (a new way of working that doesn’t involve oiling out) http://www.tate.org.uk/art/research-publications/camden-town-group/sarah-morgan-joyce-h-townsend-stephen-hackney-and-roy-perry-canvas-and-its-preparation-in-r1104353; Lord Leighton (in a letter to Prof. Church he writes about using rectified petroleum instead of the normal process of oiling out) and is mentioned Leighton’s Painting process forms from the Royal Academy noting that for Daphnephoria he used Roberson’s medium for ‘rubbing in’.

[6]The Spectator no. 3750, 12 MAY 1900, p. 18 http://archive.spectator.co.uk/article/12th-may-1900/18/art

[7]Roberson Archive: MS 121-1993, p. 197; MS 313-1993, p. 88.


About the Author:

Currently in her third year studying easel painting conservation at the Hamilton Kerr Institute, Michaela Straub graduated from Aberystwyth University with a BA in Fine Art and Art History in 2012. She has undertaken internships in private studio’s, the Denkmalschutzamt in Germany and the Kunsthistorische Museum in Vienna.

To contact Michaela Straub: straubmich@aol.com