Bulletin 2 (I:2), December 1963

Home
Français
Introduction
History
Annual Index
Author & Subject
Credits
Contact

From the Laboratory of the National Gallery

by Nathan Stolow,
Chief Conservation and Scientific Research Division

Pages 1 | 2 | 3 | 4 | 5

The Virgin and Child

Attributed To The Labrosse Atelier

This work is a polychromed wood sculpture transferred to the National Gallery of Canada from the Musée de Chambly. Again no technical history was available from previous records. (13) The carving was very generously coated with a glossy, white enamel paint which obscured to a great extent the original surfaces of paint and gilding. The work consists of a great number of glued pieces of softwood (probably Eastern Canadian White Fine), and was apparently not carved from one block. The overall appearance of the sculpture before treatment is shown in Fig. 6. The overall height (excluding base) is 63 inches, and the maximum circumference 70 inches. The periodic splitting and separating of the glued pieces of the sculpture had necessitated restoration treatment in the past, and judging from the fills and especially the application of the white paint, such treatment had been most inexpertly carried out.

It was first necessary to locate the original polychromy underneath and to survey the extent of its coverage on the wood. For this purpose the technique of mounting and cross-sectioning of paint particles was used. (14) While the layer structure varied with the particular location from which the cross-section was taken, a fairly consistent structure was found in the cloak and drapery of the Virgin. This is illustrated in Fig. 7. Here there are six layers of paint and other coatings: from the top downwards they are enamel white, grey white paint, another thin grey layer visible only by ultra-violet incident light fluorescence, (15) another grey layer of paint, white lead layer (basic lead carbonate), chalk ground, and finally the wooden surface. The white enamel paint covered most of the carving, and in particular covered in a single coat the inserted fills of wood of previous restorations. Areas not covered by the enamel were the feet, face and hands of the Virgin, the Child's head, and the areas of gilding. The flesh and hair colours had been coated with a heavy layer of darkened varnish, and in the Child the pinkish skin had been obscured by the white enamel paint.

Cleaning tests, in conjunction with cross-section analyses, showed that the brownish varnish on the face and feet of the Virgin and on the Child's head, could be removed with a mixture of shell sol, acetone, and cellosolve in the proportions of 3:1:1. There was, however, some risk of damage by solvent action in the removal of the varnish from the hair regions. The original brown hair was probably resinous in composition. The white enamel over the pink of the Child's body was removable by swelling with ethyl alcohol followed by mechanical scraping. The removal of the major overpaint, i.e., the white enamel paint, required considerable study. It was found that the most efficient means for its removal was to employ a very selective and penetrative swelling agent which would act most quickly in the penetration and swelling of the two top layers of overpaint (e. g., layers 6 and 5 of the cross-section in Fig. 7), such a solvent being dimethyl formamide. (16) By a pre-determined method of application of this solvent, i.e., by adding the right amount of solvent to a given area of overpaint, and by applying the scalpel at the right time of softening or swelling, it was possible to remove the two top layers before there was any appreciable swelling action on the layers underneath. Any residual absorbed dimethyl formamide would be permitted to evaporate away. The appearance of the partly cleaned sculpture is shown in detail of Fig. 8. The cleaned areas reveal the ancient polychromy with its encrusted layer of dirt (probably layer 4 of Fig. 7).

On the basis of the condition and examinations made, treatment commenced. This involved complete removal of overpaint, old fills, embrittled glue in joints, the filling of losses where feasible, reconstructing the lacunae (it was decided not to reconstruct the Child's feet), inpainting, regilding, and applying fungicide to the hollow interior of the carving. The following are brief notes extracted from the treatment report: (17)

The varnish on the hair of the Virgin and that of the Child could not be safely removed with solvent as had been judged during the examination tests. It was found that the hair colour was very thinly applied over a whitish ground, and was very readily removed by solvent action. Since no aesthetic gain could result, the cleaning of the hair was abandoned. The removal of the white enamel proceeded quite smoothly using the dime thyl formamide. Its removal revealed considerable damages in the numerous joints, restorations, embrittled adhesive, and a general condition which could not be determined except by cleaning. The losses were compensated for by filling and levelling off with the surrounding areas of polychromy, using for this purpose calcium carbonate mixed with parchment size adhesive. The inpainting of these filled areas was carried out by means of pigments ground in Rhoplex emulsion. (18) This contributed to the overall matt appearance of the cleaned sculpture.

The removal of the white enamel paint revealed worn and rubbed gilding on the edges of the Virgin's robes, and also on the ball held in the Child's hand. In some areas the gilding was shown to be metallic or bronze leaf, apparently of more recent restoration (see for example the cross-section of Fig. 10). The rubbed, eroded, or overbronzed gilding was redone using gold leaf applied over a preparatory layer of red armenian bole. Toning of the gilded surface was achieved with a suspension of burnt umber in a solution of polyvinyl acetate in toluene.

The base was detached, revealing the hollow interior of the sculpture and confirmed the 'patch-work quilt' piecing-together of the wood. After vacuuming, the interior was sprayed with a fungicide consisting of 10% paradichlorobenzene in carbon tetrachloride. The base was replaced with one of sounder construction and more harmonious with the completely restored Virgin and Child (see Fig. 11).

Next Page | The Toilet of Venus

1 | 2 | 3 | 4 | 5

Top of this page