Jade Hill is an Edinburgh-based paintings conservator, and our most recent fellow at The Phoebus Foundation. Over the past few months, she has applied her conservation expertise to treat several works of art. Notably, she carried out image reintegration on Portrait of Archduke Maximilian and Portrait of Archduchess Elisabeth, two portraits by Jakob Seisenegger (1505-1567), and assisted Jill and Ellen Keppens in the complex removal of varnish and overpaint on the Seige of Horn by Peter Snayers (1592-1667).

One of Jade’s key contributions during her fellowship is the full restoration of Saint Rosalia, an eighteenth-century Baroque painting by the Mexican artist, José de Páez (1720-c.1790).

Saint Rosalia is a small, religious scene on a copper support, in the style and palette typical of the artist. The composition centres around two prominent figures: Saint Rosalia of Palermo, Sicily is on the right, depicted in a dark-blue dress, wearing a crown of red roses and holding a crucifix. A winged angel, dressed in red, is to her left, gesturing towards heaven in the top left corner. The  figures appear inside a cave, with a distant view of a building on the shore-front, likely to be Palermo Harbour, and a skull appears in the foreground;  these details are characteristic to depictions of the saint.¹

An inscription in the lower left corner, loosely translated from Latin to English, reads: ‘I, Rosalia, of Sinibaldi, of Quisquina, and of the roses. In adoration of my lord, Jesus Christ, I dwell in this cave to be closer to Him.’ Sinibaldi is the family name of Rosalia and Quisquina is the Sicilian municipality of her family. Rosalia lived in a cave near Palermo as a hermit in devotion to her faith.

Though undated, the painting was signed ‘Jph. de Paez fecit en Mexico.’ The artist previously signed works ‘Joseph de Paez,’ with the abbreviated signature only appearing in works completed from 1770 onwards,² thus likely dating Saint Rosalia on or after this date.

A fascinating feature of Páez’s working process is the tendency to repeat compositional elements, particularly the positioning and proportions of figures.³ In a comparison with another Páez painting in The Phoebus Foundation collection, La Divina Pastora, not only can one observe a common palette of earthy tones complimented with rich reds and deep blues, there is also a striking resemblance between the face and head positioning of the central figures. Overlaying both of the portraits digitally, they are proportionally almost identical, with only the scale and expressions differing.

Close examination of Saint Rosalia has uncovered two areas of pentimenti, or visible traces of changes made by Páez during the creation of the painting. These adjustments appear on the left shoulder and hand of the angel, and give us an indication of the creative process used by the artist to ensure compositional balance and proportional accuracy.

Copper is a very stable support, as it does not react to environmental fluctuations to the extent that canvas and wooden panel do, and therefore the paint layer did not exhibit a network of craquelure typical of a painting of this age, and there was no actively flaking paint. However, due to the smoothness of the substrate, paintings on copper panels are susceptible to paint loss from accidental damage; Saint Rosalia had suffered from this fate, with many significant losses in the paint layer resulting from abrasions, as well as from planar deformations in the support. A previous attempt at restoring the piece had covered an area to the left of the painting in thick, dark overpaint, obscuring original image and creating a disfiguring effect to the composition.

The aged, natural resin varnish was visibly oxidised, with slight yellowing and ingrained dirt. A relatively straight-forward varnish removal was carried out using free solvents; however, the thick layer of overpaint was far more stubborn and required further initiative. A selection of a-polar solvent emulsion gels were explored, with the intention of solubilizing and removing the later additions without causing damage to the paint layer; a surfactant phase allowed a limited contact with the painted surface, and the external gel phase reduced the level of penetration of the solvent. Great care was required during this stage of the treatment, as the test area was rather small, and it was important to apply the gel in a controlled manner, removing 0.5cm² areas at a time and monitoring its effect, ensuring only the overpaint was affected.

Aqueous filling materials should ideally be avoided for use with copper panels, due to the necessity of limiting any contact of water with the support. Furthermore, there is no requirement for a flexible filler typically used on canvas supports, that accommodate for fluctuations in relative humidity. Pigmented Wax Resins (PWR) were therefore explored for use; these are a suitable material because of their workability, lack of colour-shift upon application, and compatibility with conservation-grade retouching materials. The pigment content also adds toning to the infills and thus removes the necessity of a separate ‘basic retouching’ step.

It has previously been indicated that the beeswax content in commercially available PWR infills has the potential to have unwanted reactions with copper supports due to its acidity; normally, a localised isolation layer is recommended to prevent this, which reduces the depth of the already-shallow losses. Recent researchers have developed an alternative PWR, using Cosmoloid H80 and Regalrez® 1126, heated together and combined with pigments, before pouring into a mould.⁴ Following the guidance outlined in the research article, three PWR sticks were made, each using a different pigment to aid integration: titanium white, burnt umber, and raw sienna. These were applied  to the losses with the use of a heated needle, allowing precise control to add texture and match the surrounding paint layer.

Once the infills were complete, image reintegration was carried out using carefully colour-matched Golden PVA conservation paints, unifying the overall image and bringing the painting back to the way the artist had intended.

1. Palazzotto, ‘La Patrona contesa. L’iconografia di Santa Rosalia e le dispute della committenza religiosa a Palermo da Van Dyck a De Matteis’, in: V. Abbate, G. Bongiovanni & M. De Luca (eds.), Rosalia eris in peste patrona, exh. cat., Palermo, Palazzo Reale, 2018: 61-72.[↩]
2. M.M. Castañeda Hernández, José de Páez: personalidad artística, gusto e irradiación de su obra de 1750 a 1780, master paper, Universidad Iberoamericana Ciudad de México, 2016, http://ri.ibero.mx/handle/ibero/339.[↩]
3. Y.A. Ramírez Sánchez, ‘Il proceso pictórico de José de Páez: Ciclo de la vida de la Virgen, santuario de Guadalupe, San Felipe, Chihuahua, México’, Intervención, 2, 24 (2021): 248-302, doi: 10.30763/intervencion.256.v2n24.35.2021.[↩]
4. C.R. Pires, L. Carlyle, K. Seymour et al., ‘An Investigation into the Suitability and Stability of a New Pigmented Wax-Resin Formulation for Infilling and Reintegration of Losses in Paintings’, Journal of the American Institute for Conservation, 63, 3 (2023): 168-189, doi: 10.1080/01971360.2023.2172130.[↩]