Reconstruction of a 15th century panel by Pinturicchio

This blog post is about the reconstruction of a painting by the Italian artist Pinturicchio, which depicts the Madonna and Child with Saint John the Baptist. The painting dates to c. 1495 and is currently in the Fitzwilliam Museum Collection in Cambridge.

Bernardino di Betto di Biagio, who went by the name Pinturicchio, is considered one of the more traditional Italian painters of the early Renaissance and is best known for his frescoes rather than his easel paintings. This is in part because of a crushing condemnation of his work by Giorgio Vasari in the 16th century: “Often Fortune ignores the worthy and helps the unworthy, because it flatters her that by her favours there should be exalted those who would never reach distinction on their own.”(Journal of the Warburg and Courtauld Institutes, Vol. 25, No. 1/2 (Jan. – Jun., 1962), pp. 35-55)

I chose this painting because it came from a different period of early Italian art to the painting that was reconstructed by my co-student, Anna Don. I felt it would be good to be able to compare the two different styles of painting through first-hand experience of their preparation and technique. The lush green landscape and miniature figures in the background also appealed to me.

Virgin and child with St John the Baptist, by Pinturicchio (© Titmus)

For first-year reconstructions at the Hamilton Kerr Institute, we have the fantastic opportunity of having the paintings we are replicating in the studio with us. This is a huge advantage when trying to reconstruct  artists’ processes, as we can constantly refer to the original. Kari Rayner, 1st year intern, treated the painting in preparation for the “Madonnas and Miracles” exhibition.

Having now spent the better part of a few months with Pinturicchio’s Madonna and Child, trying to recreate how it would have originally been painted, I have been led to disagree with Vasari’s assessment of Pinturicchio’s work, and I wholly encourage you to go and admire the painting at the Fitzwilliam Museum where it is part of the new “Madonnas and Miracles” exhibition.


Unlike most panels made in Italy from this period, Pinturicchio’s painting was not executed on a poplar panel. Poplar was used more out of lack of options than a preference for the wood itself and artists would use other available woods such as walnut if they could. Adopting this view of accessible materials, the reconstructions were made on pine wood, which warped during the making of the reconstructions.

I primed two panels, one with canvas beneath the gesso ground and one without. Canvas on panels became less popular during the 15th century. However, the theory behind its use was to help cover knots and cracks in the wood and to provide a uniform surface for the gesso. The second panel was used as a test panel, which was invaluable throughout the reconstruction process.


The ground itself is made up of two parts. The first layer is Gesso Grosso, a form of calcium sulphate (for our reconstructions I used hemihydrate, better known as Plaster of Paris), mulled with warm rabbit skin glue which provides the bulk of the ground.

The gesso grosso was applied with a spatula. Taking some advice from a plasterer, I found it easiest to use a large spatula and apply the layers quickly. For my panel primed with canvas, I had problems with air bubbles in the gesso disrupting the surface. They were such an issue that after several applications I decided to wash the gesso off entirely and apply with a cloth and start again. The second time I applied the first few layers with my fingers to ensure that the canvas was fully saturated with gesso and this worked quite well.

The second part of the ground is Gesso Sottile, slaked calcium sulphate mulled with warm rabbit skin glue, that forms a silky smooth surface for the paint layer. To be more historically accurate, the sottile would have been scraped down until smooth and then rubbed smoother with the plant Mare’s Tail. However, as achieving this level of historical accuracy would also have required, according to Cennino Cennini’s Il Libro dell’Arte, several years of apprenticeship to perfect, I opted for fine sandpaper.

gesso sottile
Application of the gesso sottile (© Don)


The underdrawing was done by tracing the original painting onto a sheet of melinex (a process that is harmless for the painting but disconcerting for the tracer). Next, a  sheet of paper covered in charcoal was placed charcoal down on the primed panel and the melinex tracing placed on top. The image could then be transferred by re-tracing the tracing with a sharpened point. I finally went over the charcoal transfer with ink and brushed away the excess charcoal. This part of the reconstruction process was easy enough to do, but I was surprised by how much my tracing of the painting could still be identified as mine. I had managed to lose something of the character of the original and replace it with something of my own. It was a very visual reminder for me that this process, though historically informed, was not entirely objective.

Tracing and underdrawing (© Petrina)


Egg tempera, consisting of egg yolk and water, is a painting method that is often associated exclusively with early Italian work. It is incredibly quick drying, thus the diverse palette that Pinturicchio appears to have used for his Virgin and Child meant that a frustrating amount of time was spent grinding pigments into new paints.

The pigment that presented the most challenges to mix was lead white. Initially , it was suggested that lead white be avoided because of the associated health risks. However, I found that the titanium white I had substituted dulled down the colours and did not provide adequate coverage, which made me try out lead white under controlled conditions. I found that the flake white I was using was not mixing well with my egg yolk medium. This was resolved by adding a few drops of alcohol which acted as a wetting agent before mulling it with the egg yolk. Alcohol is not a part of any historic recipe I could find, but it is possible that the modern pigment particles that I was using were too small, causing bad dispersion behaviour. The lead white certainly acted like cocoa powder that stubbornly refuses to wet into the milk no matter how much you mash it with a spoon. The preparation of lead white was well worth the trouble as it was one of the nicest pigments to handle.

For the painting proper, I followed the advice of Cennini and began with a vermilion, white and ochre underpainting for the Virgin’s blue robe. This underpainting was visible as a discoloured red through some previous losses in the blue azurite of the robe. The purpose of this layer was to create a warm underlayer for the coarse azurite and prevent it from appearing greenish.

Underpainting stage (© Petrina)

I then started on the background, the next step suggested by Cennini, and the area that had first attracted me to the painting. On other early Italian paintings, there appears to be a very formulaic approach to applying colours, but no matter how much I looked at the landscape in Pinturicchio’s painting, I could not work out any order to his colour application. I concluded in the end that Pinturicchio was possibly a bit more experimental and might have reworked passages, overlaying different hues.

reconstruction midway
Second stage of the painting (© Petrina)

The faces followed the traditional approach to tempera painting, starting with a green earth layer and verdaccio that sits underneath the flesh tones of the faces and now, several hundred years later, is clearly visible through the upper layers of paint. This was followed by a build up of fine-hatched tempera. At first I found it very easy to overwork passages and on the face of the Virgin there are sections that have too many layers as I kept returning to tweak colours.

Early Italian pre gilding
Painting completed, pre-gilding (© Petrina)


Like many of the later Italian tempera painters, Pinturicchio also made use of oil glazes in his paintings. Red lake and copper resinate glazes were often used on red and green fabrics and draperies to create an illusion of richness and depth. It appears Pinturicchio used a copper resinate glaze in the background to create the lush, three-dimensional landscape, and red lake on the draperies to increase the illusion of depth. Despite having several shades of hand-made red lake,  I found it was the most difficult pigment to match.  It was too pale, leading me to believe I had done far too little modeling in the underlayers. I even tried to apply the madder in thicker layers to see if I could achieve a darker effect. However, this caused wrinkling of the glaze upon drying. I did eventually find a madder that was a much deeper colour and I managed to achieve something closer to the original intensity. The result was much better but proved that I could still have done more under modeling of the draperies.

Glazing the areas of foliage with copper resinate (verdigris dissolved in a oil and resin medium) was an exercise in working out how much modeling was needed in the tempera underlayers. My conclusion was  that maximum modeling should be done in the tempera layers and minimal modeling in the glazes, which I applied in thin layers to try and achieve the textured, almost impasto effect of Pinturicchio’s surface.

glaze texture
Detail of the impasto-like effect in the glazes (© Petrina)

Mordant Gilding

The mordant gilding presented a completely new set of challenges for this reconstruction. This was because the gilding had adhered over very coarse pigment, (high grade azurite) and/or over oil glazes. I noticed that in a small trial area, these painted layers had acted as a mordant in their own right and prevented the brushing off of excess gold leaf.

Mordant gilding (© Petrina)

Several treatises recommend glare (an egg white-based temporary varnish) as an isolating layer between oil and mordant. I tried a recipe which included some sugar in the hope that it would be easier to remove, and was fairly successful but there were still issues with removing excess gold. Many treatises recommend that certain processes should be carried out at certain times of year to allow for favourable weather conditions. For example, the gesso application should not be done when it is too hot to prevent cracking. I suspect mordant gilding over the glaze during drier atmospheric conditions might make a difference.

The other issue I faced was entirely my fault and could have been prevented. When applying the mordant for John the Baptist’s halo, I realised that it was indistinguishable in colour from the green background, which resulted in a halo that was not as perfectly rounded as the original and gave John the Baptist’s halo the illusion of trying to turn itself into a wizard’s hat.

Detail of St John the Baptist, gilding stuck in the glazes (© Petrina)

The final touch was shell gold added as a multitude of highlights to the landscape to create what Cennini refers to as, “a Garden of Eden”. It was unclear from the original how much of the gold was original and how much was from subsequent campaigns of restoration as some appeared very shiny. I therefore decided to add shell gold until a point I felt the image looked complete. This was influenced by working under the knowledge that the early Italians were rather fond of their bling.

Finished reconstruction (© Petrina)

It seems that in some ways, this reconstruction has been an exercise in exploring how Pintoricchio probably did not paint his Madonna and Child. This was one of the most useful outcomes of the reconstruction process, where discovering that a preconceived idea has not worked in practical terms, which allowed us to go back to the painting with fresh eyes.

The main result of this reconstruction for me was two-fold. Using (most of the time) historically accurate materials gave a practical framework to apply the theory we learn as part of the course. The other was less tangible but more profound. I gained a deep respect for Pinturicchio and other artists of the age. Throughout the process, the way I looked at the painting changed, and understanding a bit more about the framework within which early Italian artists worked only made me appreciate the achievements of their success more.

Now that you have seen the behind-the-layers of this artwork, aren’t you curious to see what it looks like on the wall? Come admire the painting at the (free) exhibition “Madonnas and Miracles” at the Fitzwilliam Museum!


Elisabeth Petrina, 1st year student at the Hamilton Kerr Institute

Elisabeth Petrina is the second of the new students. She received a fine art foundation diploma from Exeter College and BSc (Hons) in Chemistry from the University of Liverpool before disappearing to Croatia for several years to set up a forensic ornithology unit and grow vegetables. She has undertaken a project to establish a pigment garden at the Hamilton Kerr Institute that can be used as a research aid in future years.

To contact Elisabeth:

Conference Review: La Pintura Sobre Cobre, Paintings on copper and other metal plates

La Pintura Sobre Cobre: Paintings on copper and other metal plates

Polytechnic University of Valencia, 27-28 January 2017

The panel of key speakers at the conference. From the left: Isabel Horovitz, Nico Broers, Lydia-Chara Pavlopoulou, Anne Schmid, Jørgen Wadum and Alison Stock (© Chung).

The conference ‘Paintings on copper and other metal plates: Production, Degradation and Conservation Issues’ was held at the Polytechnic University of Valencia from the 27 to the 28 January 2017. The two-day conference provided a unique opportunity to explore and discuss the material history of metal-based supports, as well as their unique conservation issues.

The keynote speaker for the conference was Isabel Horovitz (The Painting Conservation Studio, London), a longstanding expert on the history and conservation of copper supports. Her talk provided an overview of the use of metal supports by artists in Europe. The practice commenced with the experimental adoption of copper plates in sixteenth century Italy, and continued even during the nineteenth and twentieth centuries, as seen in the work of artists such as William Blake, Angelica Kauffman and Lucian Freud. In discussing the history of copper supports, Ms. Horovitz also addressed the manufacture and preparation of copper plates for painting, including the hammering of the metal itself, as well as artists’ application of ground layers.

The artist’s process of making in relation to paintings on copper was further elucidated by Alison Stock (City & Guilds of London Art School, London), who gave a talk about her reconstruction of Hendrick van Balen’s Adoration of the Shepherds (Fitzwilliam Museum, Cambridge). The talk discussed the preparation of the copper support based on instructions derived from historic treatises. Through a thorough technical examination of van Balen’s painting, Ms. Stock aimed to create a replica with a similar material structure to the original work.

Alison Stock presenting her technical research and reconstruction of Hendrick van Balen’s painting ‘Adoration of the Shepherds’ (© Chung).

Jørgen Wadum (CATS, Copenhagen) also delivered a talk that delved into the raw materiality of paintings on copper, with focus on the trade of copper and paintings on copper within the Antwerp market during the seventeenth century. Interestingly, Spain became a major destination for the export of paintings on copper, from whence they continued their journey to the Spanish colonies in South America. Although it was not speculated by Wadum, one cannot help but relate the popularity of these Antwerpian copper-based artworks to the comments made by Horovitz regarding the early appreciation of copper plates as a durable support for paintings. Indeed, when found in good condition, paintings on copper seem to have an almost ageless surface, as if it has “just left the artist’s studio”.

The materiality of copper paintings was also explored by Anne Schmid (Fondation Beyeler, Basel), who discussed the interesting case of ‘silvered’ copper plates. The examination of copper supports has revealed this rare variation, whereby a silver-coloured metallic layer was applied to the surface intended for painting. Analysis of these layers has shown that these ‘silvered’ layers often consist of tin or tin-lead alloy. Through her research, Schmid was able to provide a number of hypotheses regarding the purpose of these metallic coatings, with the most compelling conclusion being that the practice derived from the crockery industry in Rome where similar coatings were applied to prevent the green degradation products associated with copper objects.

Additional talks were also given by Nico Broers (École Supérieure des Arts Saint-Luc, Liège), Lydia-Chara Pavlopoulou (freelance conservator, Athens) and Laura Fuster López (Polytechnic University, Valencia). All three speakers focused on the physical and chemical characteristics of the copper support, as well as its interaction with overlying oil paint films. Both Broers and Pavlopoulou addressed the formation of copper carboxylates at the interface between the copper plate and ground layer. Such layers have been identified on a number of oil paintings on copper, which has led to the hypothesis that the formation of copper soaps contributes to the delamination issues often associated with these supports.

The final talk was given by Professor Leslie Carlyle (Universidade NOVA de Lisboa) during the second day of the conference. In her talk, Prof. Carlyle presented the results of two MA theses undertaken at the University of Lisbon. The first thesis was conducted by Maria Leonor Oliveira, focusing on the consolidation of oil paintings on copper. The basis for Oliveira’s research was an undated unsigned oil painting entitled ‘The Visitation’, which exhibited severe flaking.

In order to identify the most appropriate consolidant for her treatment, Oliveira tested several well-known synthetic resins (Paraloid B72, Mowilith 20, BEVA 371b and Laropal A81), chosen for their exclusion of water-based components. The adhesion of the polymers to copper surfaces was tested through coating small pieces of copper with the various resins, as well as attaching paint flakes to a copper surface. Based on the results of these tests, both BEVA 371b and Laropal A81 were excluded as possible consolidants due to their undesirable physical properties upon drying (BEVA 371b formed a very thick, soft coating, whilst Laropal A81 formed a very thin and brittle film). Out of the remaining polymers tested, Paraloid B72 was preferred over Mowilith 20, as it formed a film with greater hardness and tenacity.         

The second thesis discussed in Carlyle’s talk was the work of Daniel Vega, whose research centered on the development of an infill formula suitable for oil paintings on copper. Due to the corrosive action of water on copper, traditional aqueous fill materials are often considered unsuitable for filling on copper supports. For the same reason, beeswax-containing fillers such as Gamblin® Pigmented Wax-Resin sticks should also be avoided, as the fatty acid component of the filling material facilitates the production of copper carboxylates and thereby promotes further corrosion.

Vega explored the physical properties of various microcrystalline and synthetic resin mixtures in order to produce a filling material that had the desired characteristics in terms of both handling and reversibility. The results of the research showed that formulations made with Techniwax 9426 and Regalrez 1094 or 1126 had the desired qualities. Both components have an acid value of zero and are therefore likely to be chemically stable in relation to a copper support. In addition, both materials are readily available to conservation professionals and practitioners can easily replicate the recipes outlined by Vega. The research summaries presented by Prof. Carlyle provided clear and practical information, which will no doubt be of use to conservators dealing with the treatment of oil paintings on copper in the future.

In addition to the talks presented, the audience was also given short overviews of the posters on display at the conference. The posters presented a range of topics including the technical investigation of a number of artworks on copper, as well as specific conservation concerns. Sally Higgs (Courtauld Institute of Art, London) presented her technical examination of a portrait of cardinal Antoine Perrenot de Granvelle by Scipione Pulzone (Courtauld Gallery). Ms. Higgs evaluation of Pulzone’s portrait mirrored the observations made by Horovitz in her keynote speech; namely that the choice of copper as a support was a conscious choice made by the artist in order to create a durable, everlasting image.

Overall, the two-day conference provided a dynamic forum where the unexplored issues of metal supports could be discussed and future research questions could be posed. Our knowledge of the production, use and degradation patterns of paintings on copper has come a long way since the ‘Copper as Canvas’ exhibition was held at Phoenix Art Museum in 1998. However, perhaps the clearest outcome of the La Pintura Sobre Cobre conference was the need for further investigation into the physical and chemical characteristics, as well as potential conservation methods for this relatively under-studied, yet fascinating artists’ material.

Emma Jansson, 1st year intern at the Hamilton Kerr Institute.

Emma Jansson graduated from the Courtauld Institute of Art in 2016, having completed the three-year Postgraduate Diploma in the Conservation of Easel Paintings. She also holds a BA in History of Art/Archaeology and Japanese Studies from the School of Oriental and African Studies, University of London. Emma has experience working in both private conservation studios in London and public institutions. Her most recent placements include internships at the Victoria & Albert Museum and the National Maritime Museum in Greenwich, as well as an in situ project at the Houses of Parliament, Westminster Palace. She is also involved in the technical analysis of artworks. Her final-year thesis at the Courtauld Institute focused on the materials and technique of the Impressionist artist Alfred Sisley. Emma is continuing her interest in technical art history at the HKI, where she is involved in several research projects, including a study on the uptake of artificial ultramarine by British artists in the nineteenth century.  

To contact Emma: