By Sujin Jung, Graduate Diploma Conservation Studies, specialising in Ceramics and Related Materials student
In December 2019, we were delighted to be asked by The Courtauld Collection to treat a small two-handled Italian maiolica armorial bowl (inventory number O.1966.GP.246), made in the Marche region, probably in Pesaro or Castel Durante, around 1650-1700.
Maiolica refers to tin-glazed earthenware ceramics, which were first made during the Italian renaissance. The object in question has a light grey coloured opaque tin glaze, forming a background on which yellow and blue birds have been applied with thin black lines. The vase’s decoration depicts a coat of arms and grotesque design motifs. Two handles decorated with a yellow tone are adorned with ornate grotesques sticking their tongues out with their hair stretched to join the body of the object. This decoration could indicate maritime symbolism. On the base is a paper label with the number 246 attached (the inventory number of the former owner, Thomas Gambier Parry). The inventory numbers were kept and integrated into the accession numbers when the collection was acquired by The Courtauld in 1966.
The object was generally in good condition when it arrived into the ceramics conservation workshop. There was a layer of dirt and dust visible on the surface of the object. Upon inspection, it was apparent the vase had previously received conservation treatment (see figure 1 and 2.) and there was a misalignment between the shards which might have been caused by the nature of the breaks. Despite the misalignment, the object was in a stable condition, as a gentle auditory test produced a transparent and clear ringing sound. Previously restored parts were visible as running cracks around the body and stem of the vase, with some cracks re-opened and numerous small losses. The excess adhesive which had been used for the previous restoration was exposed on the break edges.
There were numerous tiny losses of glaze along the rim (see figure 3 and 4.) and these were covered with ingrained dirt. Tiny pinholes in the glaze might have been due to the fabrication and there were a few discolorations in the glaze of both handles. On the stem of the vase, there was glaze missing, possibly caused during firing. There were two significant losses on the rim (see figure 5), and on one of the handles, the tongue was missing (see figure 6); these appeared to be fresh damage.
Dry cleaning was done gently to avoid any physical damage using a soft brush to remove overall dust and dirt from the object. As the break line inside was quite open and showed excess adhesive and dirt, a scalpel was used to remove the excess of adhesive, and museum dirt was removed using a stencil brush.
Wet cleaning solutions were tested on small areas, with no adverse effect on the object. The surface was therefore cleaned using deionised water on cotton swabs. Before going to the original surface, the wetness of the swabs was moderated by absorbing wet swabs in tissue paper. Losses around the rim had quite an amount of dirt carefully removed by damp swabs.
The missing tongue of one handle was moulded from the other tongue and the fill was refined away from the object using files and a spatula. To protect the original surface of the tongue, laboratory sealing film was used before moulding (see figure 7).
To obtain a perfect key to bond, modelling wax was used to fill the gap between the modelled tongue and the object. The modelled plaster/modelling wax tongue was placed in a plastic container and liquid silicone was poured into the container. After a few hours, the plaster/modelling wax tongue was removed from the silicone mould. Then liquid plaster was introduced to the silicone mould. The moulded plaster tongue (see figure 8) was set after a day and removed from the silicone. The cast tongue was then bonded.
Filling and micro-filling
Small losses were directly filled and shaped with modelling tools and spatulas. Flügger was applied to the previous stable but open break edges with fingers, as the break line was located inside of the object, approaching with the spatula was difficult. Some micro-filling to fill the break line between the yellow original surface inside and white part outside of the object was tinted with powdered pigment to minimise and facilitate colour retouching.
Benchtop tests were carried out to compare the characteristics and the differences between the retouching and glazing materials. As the object was quite glossy with a thick glaze on the tongue, both matte and glossy texture on the rim, Golden restoration glaze gloss and matte were decided as glazing media.
The filled missing areas, micro-filled break lines, and the plaster moulded tongue were retouched using Golden Fluid acrylics with water and Golden restoration glaze gloss and matte. To match the exact colour of the original surface, every colour retouching process was accompanied with a colour matching test to see the glossiness and thickness fit to the original surface (see figure 9). Micro-filled lines were retouched using a miniature brush to avoid affecting the original surface. As some of the micro-fills were tinted, retouching could be minimised. Colour micro-fills along the break lines were retouched and polychrome decorated micro-fills were retouched with only acrylic paints without the glaze.
The plaster cast tongue was partially retouched with yellow and then bonded to the object. After drying it was retouched completely sympathetic to the original surface. Glazing medium was applied 2-3 times on the surface to mimic the thickness of the original glaze. Golden restoration glaze gloss and matte were used on fills on the rim area to imitate damaged and matte original surface near the fill.
After the conservation process was completed, light cleaning to remove any traces of handling during treatment, although kept to a minimum, was carried-out with a soft dry brush and slightly dampened cotton wool swabs, avoiding the conserved areas.
Images after treatment
To ensure the longevity of the object, it should be handled with care to avoid physical damage. A soft brush is recommended for surface cleaning and protecting the object from dust.
Fluctuations of temperature and humidity should be avoided, as should contact with water or any other liquid as the treatment materials could be affected, the break edge is exposed and the tin glaze is fragile. It is recommended to avoid sunlight or other forms of direct heat. It should be placed on a flat area with shock absorbing material.
The J. Paul Getty Museum Collection (2001) Italian ceramics. Los Angeles: Christopher Hudson.
Wilson, T. (2017) Italian maiolica and Europe. Oxford: Ashmolean Museum.
(Accessed 6 Jan 2020)