Bilateral Icon/Mother of God Hodigitria—The Baptism of Christ

As part of the ‘Icônes du Liban’ (‘Icons of Lebanon’) exhibition organized in 1996 by the Mairie in the 5^th arrondissement and the Centre Culturel du Panthéon in Paris, this bilateral icon of ‘The Mother of God Hodigitria/the Baptism of Christ’ from the Kaftoun monastery in Lebanon, was examined and restored in the Centre for Research and Restoration of the Museums of France (C2RMF, Centre de Recherche et des Restauration des musées de France) by Nicole Delsaux (pictorial layer).

The icon’s frame has a very unusual decoration of medallions, whose iconography suggests the work was produced between the eleventh and thirteenth centuries. However, the presence of green on the frame meant that an in-depth study was required before taking decisions on how to restore it. To understand the painting techniques used, the types of materials used were identified on stratigraphic sections by the Scanning Electron Microscope (SEM) coupled with an energy-dispersive X-ray spectrometer (EDX)[1]. The main results are described below.

The support is comprised of two panels of resinous wood. A canvas support has been applied over the entire front surface of ‘The Mother of God Hodigitria’. A preparatory 1 mm coat was  applied to the canvas. This is characteristic of the undercoats used in the Mediterranean area: calcium sulphate combined with proteinic glue. The same technique seems to have been used for the gold elements on the rear side of The Baptism of Christ (haloes etc.). There are red Greek inscriptions under the two lateral angels on either side of the Virgin and Child. A mixture of pigments—red ochre and vermilion—has been used to represent the Virgin’s cloak. However, a rare and expensive blue pigment—lapis lazuli—has been used for the Virgin’s headdress, Christ’s clothing, and the angel’s clothing. The same pigment has been used for the icon on the rear side.

The icon’s panel has been recessed and the raised edges, which serve as a frame, have been decorated with small moulded medallions. The raised decorations in ‘gesso’ have been attached to the undercoat of the frame with rabbit-skin glue. The ornamentation is completed by tin leaf that is also present on the edge of the frame on the rear side. During previous, non-documented restoration work, ‘bronze’ leaf (yellow-coloured alloy of copper and zinc) was applied with an oil-based adhesive to produce a gilded look and conceal the damaged areas in the decoration. Intense green deposits then developed around the icon’s edges.

To understand the process of formation of these alteration products, a whole range of physico-chemical analysis techniques have been used: Fourier Transformed Infra-Red (FT-IR) Spectrometry and Gas Chromatography coupled with a Mass Spectrometer (GC/MS) identified the organic deposits present in the alteration products. Finally, Electron Spin Resonance (ESR) has revealed the degree of the coordination of the copper ion in the deposits present around the edge of the icon. The data obtained indicates that the green layer on the frame is comprised of a mixture of copper fatty acid complexes similar to those obtained by the action of a fatty acid on the verdigris or the copper. These fatty acids in fact originate  from the oil-based adhesive that had been used to apply the ‘bronze’ leaf on the icon’s frame during previous restoration work.

The copper contained in the metallic leaf has therefore reacted with the oil size and produced the green colour on the surface of the work’s frame in relief. Since the green deposits had appeared after the work’s completion, they were removed during restoration to reveal the original—though slightly damaged—decoration on a particularly impressive work. The work's decay process very much depends on the conditions of its conservation.