CCI Newsletter, No. 33, May 2004

Treatment of a 16th-Century Spanish Panel Painting

by Wendy Baker, Conservator, Treatment and Development Division - Fine Arts

Descente de croix was sent to CCI for treatment pending an exhibition of artifacts from Nouvelle France scheduled to open in the spring of 2004 at the Canadian Museum of Civilization, Gatineau, Quebec. The painting, which belongs to the Musée des Augustines du Monastère de l'Hôtel-Dieu in Quebec City, was acquired by them in 1940, donated by Mme. Rousseau, the widow of Dr. Arthur Rousseau. He was, most notably, the founder of the Laval and Saint-Sacrement hospitals in Quebec. How and when the panel arrived in Canada, and how it came to be in the possession of the Rousseau family, are not known.

Origins

The artist is anonymous, but the painting is considered to be of 16th-century Spanish origin. Descente de croix bears some resemblance, in its composition, to a sacred work by Pedro Machuca, The Deposition (1520–1525, Madrid, Prado), although stylistically the two are quite different. Some suggestion of portraiture in one of the figures of Descente de croix could date the painting to the latter half of the 16th century when realism in Spanish devotional painting became the trend. It is possible that this panel was commissioned by a wealthy merchant or city official whose portrait is painted into the composition. The panel painting likely adorned a chapel or altar in the donor's church and may have formed part of a larger, sacred composition.

Biblical Iconography

The biblical figures standard in "Deposition" scenes are found in Descente de croix. Joseph of Arimathea, a wealthy member of the Jewish Sanhedrim, appears in a red robe to the left of the composition. He holds the sangraal; the "Royal Blood" or Holy Grail. It was Joseph of Arimathea who demanded the body of Christ and who offered up his own tomb for the burial. He is almost always depicted close to the body of Christ, along with Nicodemus. These two biblical figures are associated with the embalming and entombment of Jesus. Nicodemus (centre right), clothed in a green robe, holds the feet of Christ. The figure in the lower left of the composition with an arm around the Virgin's waist is Saint John the Evangelist. The woman kneeling at the extreme left, with loosened hair, is Mary Magdalen. The two women directly behind the Virgin are Mary, the mother of James the Less and Joseph, and Salome, mother of the sons of Zebedee; possibly the sister of the Virgin. This latter Mary, Salome and the Mary Magdalen are described in the Gospels as present at the Crucifixion. They are also the three women who discover the empty tomb on Easter Sunday — hence their iconographic importance in paintings of the Deposition. Saint Longinus is also standard in Deposition scenes. He is the Roman soldier who pierces Christ's side with the "Spear of Destiny." Longinus is always shown wearing armour. In Descente de croix, he is placed in the extreme right of the composition, behind the donor, and holds the "Spear of Destiny." The one crucified thief painted into the composition is likely the Good Thief — the one who asks for forgiveness and ascends into Heaven. The donor appears in the lower right and is dressed in a remarkable patterned costume, likely his best regalia. He points, as is customary, towards the Virgin Mary.

Panel Construction and Painting Materials

This panel is constructed in a fashion typical of Spanish panel paintings of the period. It is composed of five poplar planks assembled before the wood was completely seasoned. The original method of connecting the planks was by nailing from the front of the planks to the cross battens placed on the back. The nail heads were sunk into the panel front and the nail ends were clenched over the battens on the back. The original battens have long since been removed and the planks reduced in thickness during a previous restoration. The planks, once joined, were allowed to fully dry and shrink slightly. The ensuing and expected gaps between planks were then filled, by the panel-maker, with a putty and a mat of stiff grass fibres glued to the panel's front surface. Multiple layers of gesso (a mixture of calcium carbonate, gypsum and glue) were then applied over the grass fibres, sanded smooth and a composition sketched out. Before executing the composition in colour, the artist brushed a thin coating of burnt umber in oil over the gessoed surface and proceeded to paint out the composition in oil and tempera using natural ultramarine, azurite and smalt for the blues; cinnabar or dry-process vermilion and an organic pink/red for the reds; and malachite and terre verte for the greens. Lead white, lead-tin yellow, orpiment and various iron-oxide pigments were also identified in the painting.¹

Condition

The panel has undergone at least one previous major intervention, and several minor restorations. As a result of this previous intervention, a convex warp at the back of the planks was removed by planing down the plank back until a flat surface was achieved. The overall plank thickness was reduced to 1.2 cm. The now flattened back of the panel was reinforced by a carpenter-restorer with a wood framework made of old stretcher members glued into place around the perimeter as well as across the planks. From the back, gaps at the joins between planks were roughly filled with a gilder's putty that, in most cases, did not penetrate through to the front of the panel. Heavy cracks and losses at the joins were filled from the front of the panel with a variety of putties. Filling of the losses along the joins at the front of the panel appears to have been an ongoing process. The nature of fill materials varied with each subsequent restoration. The wood, both of the panel and batten framework, was weakened by wood-boring insects and, although not completely honeycombed, the wood is fragile. A number of cracks have developed in the planks. These penetrate through to the paint layer and likely occurred after the planks were thinned. Large islands of delaminated gesso and paint can be found over much of the surface of the panel. Fortunately, losses to paint and ground, apart from those at the joins, are mostly located along the edges of the panel. Failure of adhesion between paint and ground are very localized. Most problematic, from an aesthetic point of view, are the numerous heavy fills that bridge the unevennesses in the joins between the planks. These fills stand proud of the surface and are cracked. The overlying retouches are often visibly different in colour to the original paint. Occasional overpaints were applied to the surface and conceal damages to the background. A heavy brushed layer of varnish, that is identified as either a mixture or a layering of shellac and colophony,¹ was also present on the surface.

Treatment

The assessment and treatment of Descente de croix at CCI has passed from hand-to-hand within the Treatment and Development Division. The hands involved include those of Debra Daly Hartin, Agatha Souchon and Wendy Baker (Fine Arts), and Alastair Fox (Furniture).

The first step in treating this panel was to remove the heavy layer of highly insoluble varnish and overpaint. After testing, a method was developed that swelled the varnish layer and allowed it to be removed almost completely mechanically. A selected surface area was swabbed with benzyl alcohol and then covered with Gortex for between 20 and 30 minutes. The varnish, along with the overpaints, swelled and could then be removed with dry swabbing. This approach left the surface completely intact, even over the sensitive red paint layers. Step two involved tapping the panel face lightly to "sound out" areas of delamination and consolidating these regions using a 6% solution of isinglass in water and ethanol. Step three consisted of removing overfills at the joins.

Structural stabilization of the joins and the worst of the cracks was the next phase of treatment. Cracked restoration putty on the back of the painting was removed from those joins where there was no support for the paint and gesso at the front. Once the old putty was removed, a thinned-out mixture of West System 410 Microlight Fairing Filler suspended in a 5% solution of Acryloid B72 in n-propanol and butanol was injected against the back of the paint and gesso layers through the gap at the back of the panel. This provided a thin, elastic support for the overlying gesso and paint layers. A hide glue-coated basswood insert was then pushed into the gap until contact was made with the wet Microlight Fairing Filler. The wood insert was shaved level once the glue dried. Cracks in the planks that did not meet level at the front of the painting were cleaned out using a fine-blade saw knife, then filled with basswood slivers, glued with hide glue and weights were placed above the repaired join until the glue dried. All losses to paint and gesso have been compensated with a calcium carbonate and rabbit skin glue mixture.

The next steps were infilling, inpainting, varnishing and then securing the panel in a framed humidity-controlled box. The fills were toned with watercolours, followed by powder pigments suspended in PVA inpainting medium. A varnish layer of MS2A was applied. This has the appearance and wetting characteristics of the natural resin dammar, but does not have the latter's brittleness.

Reintegration of smalt-painted regions was carried out in order to complete the restoration. Smalt, an historic pigment made of ground glass coloured blue by cobalt, has faded, losing its blue colour (see the robe of the figure with upraised arms below Christ and to the right of Joseph of Arimathea). The brown colour that now remains is basically discoloured medium. Affected areas were infused with a 30% solution of Regalrez 1094 in naphtha² in an effort to saturate out the blanching or slightly white and foggy appearance of the old smalt layer. This helped to saturate out the discoloured medium, but still left it slightly blanched and brown. The blanched and brown regions were glazed with cobalt blue suspended in PVA inpainting medium in order to reintegrate them into the composition.

To ensure the long-term stability of this work of art, the 19th-century frame that arrived with the painting from the Musée des Augustines has been modified with a sealed back, a glazing layer and provision made for maintaining a stable interior humidity.

1. Analysis of Samples from Descente de croix, Analytical Research Laboratory Report, No. 3988 (June 6, 2001); Analysis of Supplementary Samples from Descente de croix, Analytical Research Laboratory Report, No. 3988.2 (October 9, 2001) and No. 3988.3 (December 18, 2002).
2. Suggested by Stephen Gritt, Chief of Restoration and Conservation, National Gallery of Canada, personal communication.