Before treatment, recto
By Derrin Compton, Rosie Blay, Kate Galatian and Shawn Kwan, Conservation of Ceramics and Related Materials students
In 2018, we were delighted to be asked by The Courtauld Gallery in London during their temporary closure for a major refurbishment known as 'Courtauld Connects', to treat a large maiolica dish, possibly made in the 17th century in Savona, Italy (Figure 1). The term 'maiolica' refers to tin-glazed earthenware ceramics first made during the period of the Italian Renaissance. The light-coloured, opaque tin-glaze provided a background over which cobalt blue decorations were applied, visually similar to blue and white Chinese porcelain which European factories sought to replicate. The dish was probably made using a plaster press-mould, over which clay would have been laid and pressed into the form to create the low relief designs on the recto.
The dish's decorations depict siren-like figures with wings and tentacles. Between the sirens near the rim are alternating large and small clamshells, and ornate grotesques are located between the sirens closer to the dish's well. The tentacled sirens and the clam shells may be indicative of maritime symbolism which would have had significant meaning to the owners at the time. The putti with the crown above the central heraldry may indicate that this plate was made to commemorate a union or marriage.
Before treatment, recto
Detail of failing previous repairs and areas of loss
The dish had been previously restored, and after an unknown number of years, the adhesive had begun to fail. This caused an unsightly gap to open, which was especially visible on the angled lip, making the object both physically and aesthetically unstable (Figure 2). The goal of the treatment was to dismantle and re-bond the shards, fill the losses and retouch the fills to be sympathetic with the original surface so that it may be photographed for the client's collection catalogue and displayed in the gallery.
Kate Galation, Derrin Compton and Rosie Blay performing FTIR analysis of the adhesive in the West Dean College science lab
First, we carried out Fourier-transform Infrared Spectroscopy (FTIR) analysis on samples of the adhesive taken from the joins to determine the identity of the unknown adhesive (Figure 3). Identifying the adhesive aided in determining its solubility, which we needed to know in order to dismantle the object and remove the old adhesive. The adhesive closely matched HMG Paraloid B-72, a commercially available, pre-packaged version of Paraloid B72. Benchtop solubility testing was also carried out, and the adhesive was found to be soluble in acetone.
Mapping the layout of shards
After the object was dismantled using an acetone vapour chamber to release the bonds, the remaining adhesive residue was removed mechanically from the edges under the microscope. During this process, the arrangement of the shards was carefully mapped to ensure that all shards could be returned to the correct position during the bonding phase.
Support system during bonding process
Due to the number of shards and the positioning of the bonds, the object was bonded in a vertical position using padded clamps held in retort stands and sand trays lined with cling film to protect the object. This positioning harnessed the shards' own weight and gravity to tighten the bonds and aid in alignment. Additionally, the shards were held in place during bonding using magic tape applied across the bond lines.
Dish bonded and supported
Once fully assembled, the dish was placed horizontally and a support system was devised to apply slight inward pressure to the shards while the adhesive cured. Because the rim naturally angles outward, supportive linen gauze, tapes and weighted film cannisters were used to lift the rim up and inward.
After the dish was bonded and the losses were filled, the desired level of retouching was discussed with The Courtauld Gallery's curator of sculpture and decorative arts and chief conservator. The decision was made to fully retouch the losses on the recto of the dish while only retouching the light blue-green background colour on the verso, leaving the darker blue leaf-like flourishes unpainted (Figures 7 & 8). This serves the purpose of blending the losses so that they are not distracting for the viewer but allowing them to remain visible upon closer examination. This gives a visual cue to someone handling or studying the object that it has been restored and should be handled with care.
This project has been a valuable learning opportunity for the four students who worked on it during their studies at West Dean College. It provided the chance for analytical examination of unknown restoration materials, debate and sharing of knowledge and ideas while making treatment decisions, and collaboration with stakeholders including curatorial and conservation staff at The Courtauld Gallery. The object is now in a much more stable condition and is ready for photography and potential display in the gallery, where it can be enjoyed by the public once again.
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Koob, S. (1986) "The Use of Paraloid B72 as an Adhesive: Its Application for Archaeological Ceramics and Other Materials." Studies in Conservation. 31 (1). Taylor & Francis, Ltd. p. 7-8.
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Thornton, D. (1997) "Maiolica Production in Renaissance Italy." in Freestone, I. & Gaimster, D. (eds.) Pottery in the Making: World Ceramic Traditions. London: British Museum Press. p. 116.
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