Tag: cleaning

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

Eton College In-Situ

In late May 2016, fellow Post-Graduate Intern Camille Polkownik, Director Rupert Featherstone, and I worked on a number of paintings at Our Lady of Sorrows Chapel on the campus of Eton College, located near Windsor Castle.

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Our Lady of Sorrows Chapel at Eton College (© Polkownik)

Over the course of three days, we treated eight paintings on site. While this in-situ project involved a number of procedures routinely carried out under such circumstances, including consolidation, surface cleaning, minor tear repair, minor filling and retouching, varnishing, and conservation-standard re-framing, we encountered a number of slightly unusual challenges that warrant mention.

Two of the paintings, upon closer inspection, were found to consist of paper adhered to canvas, which was in turn attached to keyable stretchers. These paintings appeared to have been executed in an oil-type medium and had darkened coatings, possibly tinted to make the paintings look older. Extra caution was taken during surface cleaning as a result of the potential sensitivity of the paper supports to water. After some testing, the solution settled upon was to use a lightly dampened “Blitz-Fix” sponge and dry the surface immediately with Kimwipes (acid-free tissues).

Additionally, while saliva or deionized water at pH 7 or 8 on cotton swabs would generally suffice for surface cleaning varnished paintings, two paintings – one varnished, one unvarnished – were found to warrant the use of a cleaning solution with a low percentage of an added chelator on cotton swabs due to the significant amount of tenacious grime present. These paintings, previously appearing rather dull and grey, underwent dramatic visual improvements after surface cleaning. Re-varnishing these paintings was also necessary and provided aesthetic benefits.

For health and safety reasons, the choice of which varnish to use while on an in-situ can oftentimes be limited to the synthetic varnish requiring the least harmful solvent. Fortunately, we were able to time the progress of our treatments such that we could varnish at the end of the second day prior to leaving the building, preventing human exposure to solvent vapours. This allowed us to use Paraloid® B72, for example, which we found particularly beneficial to employ on paintings with uneven gloss.

Framing and hanging presented a few challenges as well. We needed to consider several special modifications when re-framing the paintings, including enlarging the rebate of one of the free-standing frames, since the painting didn’t quite fit. The college staff also took the opportunity to modernise the hanging hardware.

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Polkownik cleaning a frame (© Rayner)

It was a privilege to participate in this project at Eton – not just because we were treated to Eton College behind-the-scenes, or because we managed to fit in a few strolls in the evenings to see the incredible number of swans on the river! It was a pleasure to work in such a lovely space, and it was a valuable learning experience to encounter such a range of conservation issues on site.

Many thanks to the welcoming and supportive staff at Eton College for inviting us to work on site. We hope that the congregation of Our Lady of Sorrows appreciates the aesthetic improvement of the paintings and that our efforts have added to an enjoyable experience of the chapel.

Kari Rayner – 1st year Post Graduate Intern at the Hamilton Kerr Institute

Ms Kari Rayner graduated with a Master of Arts in Art History and gained an Advanced Certificate in Art Conservation from New York University, USA. She also has a Bachelor of Arts in Art History, Art Theory and Practice from Northwestern University, USA. During her graduate studies, Kari interned at the Wallraf-Richartz-Museum in Cologne and worked at Modern Art Conservation in New York, NY. Her final-year internship was undertaken at the National Gallery of Art in Washington, D.C., and she will be returning to the NGA in fall 2016 to begin an Advanced Fellowship in Paintings Conservation.

To contact Kari Rayner: rayner.kari.s@gmail.com

In-situ in Southern England

From the 6th to the 8th of April 2016, Senior Painting Conservator Christine Slottved Kimbriel and I (Carlos González Juste, 2nd year postgraduate Intern) worked in-situ treating an altarpiece in a parish church in the south of England. The altarpiece is an Italian tryptich dated to the second half of the 14th century, and currently attributed to Pietro Nelli, a Sienese artist working in the tradition of Giotto.

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Details showing the egg tempera technique and the scoring and punching embellishing the gilt halo and the crozier. (© González Juste)

Like with many art objects not kept in a museum environment, this altarpiece has to face typical church conditions, including changes in temperature and relative humidity, the occasional birds droppings, and also the effects of the presence of bats which frequent the building.

Frequent and uncontrolled changes in relative humidity have an adverse effect on panel paintings, as wooden supports tends to respond with expansion and contraction. These movements affect not only the panel (- which may split if it does not have space to move in the frame) but also the paint layers and gilding, producing cracks, flaking and subsequently paint loss.

Bats are common in churches and their roots are protected by legislation. The damage produced by the corrosion of their urine and guano can be considerable, especially on the painted surface where it damages both the varnish and the paint.

The in-situ work on the altarpiece started with a full visual examination of the three panels, their structure and frame. In spite of its overall sound state of preservation, the altarpiece required consolidation of loose and vulnerable areas of paint and gilding, both on the panels and on the 19th century gilt frame. After consolidation with Lascaux© Medium for Consolidation, surface dirt and several bird droppings were removed, some areas of deteriorated varnish saturated with new varnish application and losses filled and toned. The project required us to work from a scaffolding in order to reach all areas of the panels. The surface cleaning removed a considerable build-up of surface dirt and produced a significant improvement to the general appearance of the painting, allowing the astonishingly well-preserved bright colours of the robes and the delicate flesh tones of the faces to come across once again.

Some minor technical investigation was undertaken, and in spite of the challenging conditions of working in-situ and under a time constraint, close optical examination and local infrared photography was accomplished, providing some interesting results.

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White garment of St Julian during surface cleaning. (© González Juste)

It is quite common that members of the Institute have to travel to work in-situ in churches, country houses or local museums. The reasons for choosing to work on site, rather than bringing the work to the studio, vary. It may be the right option when the painting is particularly heavy or large, or when its absence is considered unacceptable, as may be the case for an altarpiece that plays a vital part in daily worship. A painting can also be in a particularly delicate state of preservation that necessitates work being undertaken prior to moving the object, or conversely, one or more paintings are in need of only minor, preventive or aesthetic intervention that can be done more cost-effectively on site.

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González Juste undertaking surface cleaning. (© Kimbriel)

In-situ jobs are always very interesting and useful opportunities for interns, as they give us the opportunity to visit and discover different parts of the country, and especially their works of art. It also helps interns to develop their abilities when they have to face treatments in challenging circumstances and under time pressure, far away from the well-equipped studio. In-situ jobs not only provide the gratification of a job well done, but it also sometimes includes the privilege of seeing how conservation work can have positive repercussions on the daily life of the surrounding community, as was the case here. Having the opportunity to work on a magnificent altarpiece in a beautiful location was truly a pleasure, not least thanks to the helpfulness and interest of the church community, who were eager to see this beautiful work of art to which they feel attached preserved and safe for the foreseeable future.

Carlos González Juste – 2nd year Post Graduate Intern at the Hamilton Kerr Institute.

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Senior Painting Conservator Christine Slottved Kimbriel explaining the treatment and characteristics of the altarpiece to members of the community. (© González Juste)

About the author

Carlos González Juste has a B.A. in History from the Complutense University in Madrid and a Degree in Conservation and Restoration of Cultural Heritage from the Escuela Superior de Conservación y Restauración de Bienes Culturales in Madrid.  He has interned in the Museo Nacional del Prado (Madrid) and other Spanish institutions. He is currently completing his second year as a postgraduate Intern at the Hamilton Kerr Institute, University of Cambridge, where he has been working on a wide range of projects, from early Italian paintings, such as the Master of the Castello Nativity, to early C20th Russian artist A. Harlamoff, besides paintings by J. Reynolds, W. van Mieris and the C17th English painter R. Buckett.

To contact Carlos González Juste: cgjuste@gmail.com

A Painting Transformed: From Pastoral Sunset to Burning Sodom

Once in a while, an artwork is not only aesthetically or structurally improved during treatment – it is completely transformed. This is the case with a privately owned painting treated during 2015 (Fig. 1).

 

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Figure 1 Before Treatment: Landscape with Ruins, Oil on canvas. (© Titmus)

Formerly attributed to Leonardo Coccorante (1680-1750), the ostensible subject of the painting corresponds with the eighteenth-century fashion for scenes of Roman ruins. The work depicts a pastoral landscape featuring crumbling ancient columns, with the skyline of a city in the distance highlighted by the setting sun.

When the work arrived at the Hamilton Kerr Institute, an incredibly thick, discolored varnish and heavy layer of grime obscured the scene. Examination with ultraviolet light did not reveal the extent of previous restoration. During cleaning, it started to become astonishingly clear that the entire sky and city in the distance had been overpainted. Many of the buildings in the distance had been completely invented, as was the sunset. Removing the previous restoration uncovered red and yellow shooting flames in the background – in fact, the entire city was ablaze. Additionally, the figures in the foreground had been altered. The blue-robed figure was not a shepherd, but rather an angel: the staff the figure carried was a later addition, and the figure’s large, white wings had been hidden by overpaint.

These discoveries led to the reassessment of the painting’s subject matter after treatment (Fig. 2). The most plausible identification of the narrative, given the newly manifest iconography, was that of the biblical account of Lot. The Book of Genesis describes how angels warned Lot of God’s imminent destruction of the cities of Sodom. This allowed Lot, his wife, and two of his four daughters to escape. However, the other two daughters and their husbands refused to flee and thus perished. In grief, Lot’s wife looked back towards the burning city and turned into a pillar of salt. Accordingly, in the painting, there is a small white figure in the background. The scene depicted in the painting follows this narrative remarkably closely, except that it pictures four young women (instead of only two daughters) at the far left. One possible explanation is that two of the women are Lot’s daughters, and two are angels leading them to safety; however, the worn condition of all four figures makes it difficult to distinguish any wings or otherwise characteristic features.

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Figure 2 After Treatment, Landscape with Ruins, Oil on canvas (© Titmus)

The attribution to Leonardo Coccorante was also called into question because of the painting’s drastic alteration. While famous for his dramatic scenes of ruins, Coccorante is not known to have depicted biblical subjects. It was hoped that technical analysis would clarify the painting’s dating or region of origin. The work was analysed using X-ray Fluorescence Spectroscopy to detect the elements present within the paint and, therefore, infer the presence of various pigments. Dispersed pigment samples were also taken and examined with polarized light microscopy. The range of pigments identified unfortunately does not point to a specific geographic location or time period, but considering the painting’s other physical characteristics and stylistic attributes, the work most likely dates to the seventeenth or eighteenth century. This means that we cannot confirm or rule out Coccorante as the author and that other attributions should still be considered. François de Nomé (1593-1620) stands out as a particularly plausible alternative possibility: this French painter was based out of Rome and later Naples, and his dramatic scenes of ruins tend to deal with disastrous mythological or biblical narratives. In this sense, an attribution to this painter is perhaps more credible than that of Coccorante, though this text declines to make any definitive assignment.

Treating this painting was a rich experience and necessitated close consultation with the work’s owner. The treatment itself, the details of which are beyond the scope of this post, was challenging in that it required using various approaches to overpaint removal. Additionally, the heavily abraded state of the painting (which likely factored into the reason for overpainting in the first place) as well as a large loss in the lower right corner, necessitated difficult decisions regarding the appropriate extent of retouching. The transformation of the painting during treatment leaves lingering questions as to the work’s circumstances of creation and the identity of the painter.

One day, perhaps, these mysteries will be solved.

Kari Rayner – 1st year Post Graduate Intern at the Hamilton Kerr Institute

Ms Kari Rayner graduated with a Master of Arts in Art History and gained an Advanced Certificate in Art Conservation from New York University, USA. She also has a Bachelor of Arts in Art History, Art Theory and Practice from Northwestern University, USA. During her graduate studies, Kari interned at the Wallraf-Richartz-Museum in Cologne and worked at Modern Art Conservation in New York, NY. Her final-year internship was undertaken at the National Gallery of Art in Washington, D.C., and she will be returning to the NGA in fall 2016 to begin an Advanced Fellowship in Paintings Conservation.

To contact Kari Rayner: rayner.kari.s@gmail.com

The Restoration of a Virgin and Child Tondo for the Madonnas & Miracles Exhibition at the Fitzwilliam Museum

This School of Botticelli tondo depicting the Virgin and Child was bequeathed to the Fitzwilliam Museum in 1912. During the autumn of 2015 it came to the Hamilton Kerr Institute in preparation for a loan. Upon initial inspection it became clear that the heavily blistering and slightly flaking panel was likely to be under internal stress from the battens on the reverse. Due to the importance of the piece and its projected display at the Botticelli Reimagined exhibition at the V&A (2016) and the upcoming Madonnas and Miracles exhibition at the Fitzwilliam Museum (7 March – 4 June 2017), it was possible to raise funds to allow us to fully explore the cause of the blistering and undertake a complete conservation and restoration treatment. During the treatment it was found that certain paint layers and the paint medium deserved further investigation.

Structural Work

The paint and ground layers were consolidated before structural work could commence. Over time, a number of cracks had begun to form in the wooden support from the edges inwards, resulting in local tenting of the ground and paint layers. These fragile layers were secured and visibly improved during the consolidation treatment, which offered a better overall surface of the painting. The presumed tension, manifested in the cracks from the edges of the panel, was supported by the fact that the battens, which appear to be non-original, were unable to move in the original dovetail grooves. It was therefore decided to temporarily remove the battens and plane down the areas causing friction in order to fit them back into their grooves. In their slightly thinned state they will in the future provide support without restraining slight natural movement of the poplar panel in response to minor shifts in relative humidity.

Pigment and Medium Analysis

X-ray Fluorescence spectroscopy (XRF) and cross section analysis respectively were employed to determine the pigments used and to observe layer structures in order to enable comparison with other paintings.1,2 An elemental composition reading of specific passages was attained with the non-destructive XRF technique. This in turn allowed well-informed sampling for cross sections to illustrate the build-up of layers. The pigments and layer structure were found to correspond to a typical build-up in late 15th century Florentine paintings3 comprising of a white gesso layer on top of the wooden support followed by a glue priming, and in some cases a white oil priming, which was then finished off with the actual paint layers.

However, unlike many of Botticelli’s paintings, this tondo did not show the characteristic hatching typical of egg tempera painting technique. The presence of brushstrokes and impasto suggested the use of either an oil rich tempera grassa4 (an egg and oil emulsion medium) or neat oil paint. A small sample was removed from an area of loss in the light sky area in order to investigate the medium that was used. With the aid of cross section staining (using ), it was possible to conclude that very little to no protein (egg) was utilised in the paint layers, whereas the glue and ground layers stained positive for protein. A reason for this slightly unusual choice of medium for Botticelli’s workshop and period may have been influenced by guidelines of the commission, the patron, or a desired visual impact.5

Varnish and Grey Layer Removal

After successful surface cleaning and varnish removal a selectively applied grey layer extending over the flesh, Virgin’s robe, and some of the background, became apparent. This resulted in a ‘veil’ concealing the delicate shading of the faces and drapery. During inspection under the microscope, it became clear that this layer extended into cracks and was therefore unlikely to be original. Solvent tests determined a suitable cleaning solution and enabled the safe removal of the grey, obscuring layer.  The painting thus regained its original tonal values and balance of highlights and shadows.

Restoration: filling and retouching

Paraloid® B72, a stable synthetic resin, was applied as a transition layer to saturate paint layers after successful consolidation and cleaning of the painting. Subsequently, the losses were filled with a water soluble putty consisting of chalk and gelatine. These losses were then textured to emulate the surrounding area and retouched using the retouching technique traditionally employed at the Hamilton Kerr Institute: First, lightfast loose pigments bound in egg tempera medium are applied to achieve the opaque lower/baselayers of the painting, which are then followed by pigments bound in a synthetic resin, in this case Gamblin Conservation Colours™, to imitate final glazes. A final synthetic resin varnish was spray-applied to even out the gloss of the painting. The composition-gilt frame that had received glazing for the exhibition was lined with gummed paper tape and self-adhesive felt tape to reduce the risk of abrasion from the rebate to the painting’s edges. Brass plates affixed to the frame were shaped to fit the painting and hold it securely in its frame. In order to protect the painting better from fluctuations in humidity and dirt a hardboard backing was screwed onto the reverse of the frame.

Michaela Straub – 3rd year student at the Hamilton Kerr Institute

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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

  1. Bersani, P. P. Lottici, A. Casoli, and D. Cauzzi, ‘Pigments and binders in “Madonna col Bambino e Giovannino” by Botticelli investigated by micro-Raman and GC/MS’, Journal of Cultural Heritage, vol. 9, 2008, pp. 97-102.
  2. Castelli, M. Ciatti, C. Lalli and A. Ramat, ‘Il Restauro del Ritratto di Giovanne con Mazzocchio di Sandro Botticelli’, OPD Restauro: Rivista dell’Opificio delle pietre dure e laboratorio di restauro di Firenze, vol. 23, 2011, pp. 141-154.
  3. Dunkerton and A. Roy, ‘The Materials of a Group of Late Fifteenth-century Florentine Panel Paintings’, National Gallery Technical Bulletin, vol. 17, 1996, pp. 20-31.
  4. Dunkerton, ‘Modifications to traditional egg tempera techniques in fifteenth-century Italy’, Early Italian Paintings Techniques and Analysis Symposium, Maastricht 1996.
  5. Dunkerton, ‘Osservazioni sulla tecnica delle opera di Sandro Botticelli alla National Gallery di Londra’, in: D. Gasparotto, A. Gigli, F. Motta, Il tondo di Botticelli a Piacenza, Milan 2006, pp. 67 – 79.

In-Situ at Weston Park, Staffordshire

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Front view of Weston Park. (© 2016 Kari Rayner)

Weston Park is a 17th century manor house owned by the Weston Park Foundation. It has been the seat of the Earls of Bradford since the 17th Century. The house is now open to the public for visits and guided tours in addition to offering venue for conferences, weddings and other events. The collection at Weston Park includes beautiful pieces of furniture, ceramics, tapestries and an impressive collection of paintings that hang in every room, including works by Van Dyck, Holbein the Younger, Thomas Gainsborough, Sir Joshua Reynolds and George Stubbs. For 20 years, these paintings have been the subject of annual in-situ visits by the Hamilton Kerr Institute, which has mainly focused on remedial, preventive and simple aesthetic treatments. This week usually takes place during the Manor’s off-peak season, allowing the conservators, including students and interns, to stay on site during this time in the highest of style!

In February 2016, senior conservator Mary Kempski headed up a team of four interns, Kari Rayner, Sarah Bayliss, Carlos Gonzalez Juste and Sven van Dorst, for the Weston Park in-situ. The work was carried out in the Music Room, a long, spacious room decorated mainly with paintings of the family’s champion horses. Over the week, we treated 16 paintings and their frames performing such tasks as surface cleaning, consolidation, revarnishing and conservation framing.

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Setting up in the Music Room. (© 2016 Sarah Bayliss)

As with most in-situ projects, some of the paintings worked on would have benefitted from more interventive treatments, such as varnish and overpaint removal. However, as time, space and resources are limiting factors with regard to in-situ work, stabilising the paintings and improving their framing was of primary importance. However, there are several ways to improve a painting’s aesthetic in close confines; surface cleaning drastically improved the visibility in a number of paintings, and as varnishes often become less saturating over time, revarnishing as needed with a stable synthetic varnish such as RegalrezTM was an excellent way of restoring some of the saturation and depth to paintings. This can also help with evening the overall gloss, particularly when previous restorations have aged and become matter over time.

Another important part of the work as part of this in-situ project was to improve the framing of paintings. In the past many paintings were held in the frame by nails, which often damages the stretcher and tacking margins and make the painting difficult to safely remove. Framing can be improved by lining the frame with paper tape and felt, so that the paint surface has a cushion to rest against rather than wood of the frame. Fixings are replaced by brass plates that are screwed in, allowing paintings to be easily removed from the frame in the future. Stretcher keys can sometimes become loose and fall down in between the canvas and stretcher, resulting in damages to the canvas and paint layers: this can be prevented by tying the keys to the stretcher. A Tyvek® backing was added to the reverse of all of the frames to cover the backs of the paintings. This acts as a barrier, protecting the back of the painting from knocks, water damage and the ingress of dirt.

Documentation is also important part of an in-situ visit, as unframing paintings allows them to be properly evaluated for condition and potential issues that might cause problems in the future. Flaking paint and the weakening of the painting’s structural support (for example, the tearing of canvases or splits in wooden panels) are issues which can often be addressed in-situ, but may require further or more elaborate treatment in the studio. This condition checking of paintings is an important part of collection care, and can nip problems in the bud and prevent greater damage to the paintings from neglect.

 

During our in-situ at Weston Park, there were several opportunities for us to interact with the public and spread the word of conservation! This primarily took the form of ‘conservation in action’ tours, in which people were bought in to see what we were up to. This allowed individuals to directly ask us questions about the treatments of the painting, and also more generally about what we do as conservators. In addition to these tours, we were hounded by the Shropshire press. Mary Kempski and Sarah Bayliss appeared on the local radio talking about painting conservation, the Hamilton Kerr Institute and the in-situ project at Weston Park. The following day, reporters from the Shropshire Star interviewed Mary and took photographs of us in action.

It was refreshing for us to see the staff at Weston Park taking an interest in our work and to have facilitated our engagement with the local community, and we hope by sharing our experiences through this forum to equally engage a wider audience with our profession.

Sarah Bayliss – 1st year Post Graduate Intern at the Hamilton Kerr Institute

About the author

Ms Sarah Bayliss is a graduate of the Post-graduate Diploma in the Conservation of Easel Paintings at The Courtauld Institute in London. She also has a Master of Chemistry from the University of East Anglia in Norwich, UK.

To contact Sarah Bayliss: sarahebayliss@gmail.com

Workshop: The Cleaning of Acrylic Paintings

Course Leader: Bronwyn Ormsby, Principal Conservation Scientist at Tate, United Kingdom.

This two day workshop on the Cleaning of Acrylic Paintings took place in December 2015 at the Hamilton Kerr Institute (Cambridge, UK). The workshop was aimed at conservators with an interest in acrylics but not necessarily experienced with this modern material. The morning sessions were dedicated to the history of modern paints and theory of cleaning while the afternoons were more hands-on.

During these two afternoons, we tested and rated various products used for the cleaning of modern and contemporary artworks. The much-anticipated micro-emulsions, developed in collaboration with the Dow Chemical Company, were made in situ by Ormsby. They offer new possibilities for the cleaning of modern paint layers; although, when we tested them on naturally aged and artificially soiled acrylic samples, there was a natural aura of uncertainty. Depending on the solutions, some did not remove enough of the soiling, and other options worked a little too well, where some pigment was removed with the grime layer. Ormsby suggested it was possible some pigments were not locked into the film upon drying  and that as a result, there could be some loose pigment on the paint surface, hence the sensitivity to the slightest mechanical action, which underlines the importance of the application of cleaning products onto these paint layers. Also, some colours were more sensitive than others, like the synthetic organic red paint tested (PV19); the response was also quite dependent on the brand of the acrylic paint used. A lot of information to assimilate for us conservators of Old Masters!

This workshop was a real eye-opener, in the sense that despite knowing these modern paints are difficult and breed new conservation issues, having the chance to actually test many cleaning products on “safe” samples taught us a lot without the risks and consequences of experimenting on real artworks.

A poll was done at the end of the workshop to underline which solutions worked best, and which did not. It was interesting to see that once again, the results were not black and white. Two conservators with the same samples had different results, probably due to handling and application technique. Nevertheless, Ormsby recorded the results in order to understand which systems and micro emulsions worked best overall, to keep improving them for studio use. Ormsby was very down to earth and calm as well as encouraging. No, we do not understand all the problems yet and certainly don’t have all the solutions, but we are progressing towards a better understanding of the risks associated with modern paints, and the research feeding into the development of improved cleaning materials and studio practice.

Camille Polkownik – 1st year Post Graduate Intern at the Hamilton Kerr Institute

Ms Camille Polkownik graduated with a Master Degree in the Conservation and Restoration of Paintings in 2014, from the École nationale supérieure des arts visuels de La Cambre in Brussels . 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 at the Royal Institute for Culture Heritage (KIK-IRPA, Beligum), the Museum of Fine Arts of Nice (France), in private studios and at the Art Gallery of New South Wales (Sydney, Australia).

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