National Gallery of Canada / Musée des beaux-arts du Canada

Bulletin 9-10 (V:1-2), 1967

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Combination of Transfer and Marouflage 
Treatment of a Homer Watson Painting


by Mervyn Ruggles, Conservator, 
National Conservation Research 
Laboratory National Gallery of Canada

Résumé en français

Pages  1  |  2

A retrospective exhibition of works by Homer Watson, (1) arranged by Russel Harper, was sent by the National Gallery on a cross-country tour in 1963. The preparators constructed sturdy wooden cases in the National Gallery workshops for the paintings that had been assembled for the tour. These cases contained three to eight works of art, each fitted into separate carefully padded trays. Sheets of 'I.-inch-thick Ten / Test fibre-board served as insulation against extremes of temperature. (2) In spite of these elaborate precautions, the painting, The First Snow (1923), listed in the catalogue as No. 53, suffered an unusual kind of damage on its Canada-wide journey.

Investigation (3) of the wooden case and examination of the painting itself indicated that the damage was caused by mishandling of the case during transit and an inherent weakness in the construction of the painting. The support of the painting consisted of a 1/4-inch-thick sheet of heavy cardboard (4) secured by means of wire staples to a pinewood framework having a cross-section of 2 1/4 x 7/8 inches. The single horizontal crossbar was not attached in any way to the cardboard. At a later date, flat-head nails had been used to hold the cardboard more firmly to its framework along the left, lower and right edges (Fig. 1). The surface of the cardboard was covered with a single layer of grey paint. Over this was a thick impasto, almost 1/2 inch in depth; the coarse texture resembled a hardened sponge because of the numerous cavities and pockets. There was no protective resin varnish coating over the surface.

The photograph taken by oblique lighting (Fig. 2) shows the long sweeping horizontal crack, seven inches above the lower edge with a 1/8- to 1 /16 -inch displacement from the plane of the surface. This displacement was traced directly to the flexing of the cardboard support in a direction at right angles to the plane of the painting. Had the cardboard been secured to the central horizontal crossbar (Fig. 3), it is unlikely that such damage would have occurred when the crate was accidentally dropped during loading operations. Extensive separations developed between the surface of the support and the first layer of paint over it.

As it was not possible to reattach the paint laver to the support by infusing an adhesive, it was decided that the paint film on the cardboard support should be transferred (5) to a more rigid built-up panel. The description of the manner in which this process was undertaken now follows. (6) The first step was to protect the extremely heavy paint structure by applying two layers of Aldex13 wet-strength tissue paper (7) over the surface by means of dilute parchment size. The painting was then placed under vacuum at room temperature to promoie intimate contact between the tissue paper and the unusually irregular topography of the paint surface.

The support then had to be detached from the wood framework; this was done by inserting a hacksaw blade carefully and cutting through the staples and nails. Before removal of the cardboard support was attempted, a wax-resin adhesive mixture consisting of four parts beeswax, four parts Multiwax 835 and two parts AW-2 resin was brushed over the tissue facing and over a sheet of cardboard 1/4 inch thick and 1 inch larger on all sides than the dimensions of the painting. The prepared cardboard was placed over the picture positioned under vacuum on the hot table. After the painting had returned to room temperature and the rigid facing had become firmly attached to the paint surface, a surgical scalpel was used to peel away the cardboard support. Special care was exercised in the regions where displacement of the paint laver had occurred. Partial removal of the support is demonstrated in Fig. 4.

When the back of the painting had been completely exposed, lining was carried out on heavy-grade linen having 32 warp and 27 weft double threads per inch, by using the wax-resin mixture cited earlier and the vacuum hot table. (8)

After this normal lining procedure, the painting was marouflaged(9) to a built-up panel (Fig. 5). This panel was constructed with a 1/4-inch sheet of untempered masonite on the front and a 1/8-inch sheet of untempered masonite on the back, separated by 5/8 x 1 inch spacers glued in place with a polyvinvl acetate emulsion. As a fungicide and insecticide treatment, a solution of 2% pentachlorophenol and paràdichlorbenzene dissolved in carbon tetrachloride was brushed on all interior surfaces of the panel before assembly. Outer surfaces and edges were impregnated with the wax-resin adhesive prior to marouflage on the vacuum hot table. A mylar covering sheet sealed to the edges of the table with 1-inch masking tape replaced the usual rubber dam. The transparency of the mylar sheet and the more efficient vacuum seal achieved by the masking tape make this method advantageous.

Before the paint surface had reached the peak temperature of 
64 °C. the mylar sheet was folded back, and gently manipulated 50 that it could be released by the now soft wax-resin above the Aldex paper. This made it possible to take off the cardboard facing without disturbing the paint layer still protected by the tissue. The purpose of the cardboard facing had now been served. The marouflage process was then resumed under vacuum until bonding to the panel was complete. Figure 6 shows the position of the cardboard and tissue facing after the lining and the marouflage had been completed but before mineral spirit and water had been used to take away the protective tissue facing.

The displaced paint had levelled and appeared to be firmly reattached to the new supports. The margins of the lining canvas were tacked to the edges of the panel in the customary manner and specially made L-shaped aluminum strips were extended slightly beyond the face of the painting to shield the paint film from abrasion by the frame rabbet.

Small insertions of chalk gesso were required to compensate for an old 3/4 x 3/4 inch paint at the upper left corner, two 1/4 x 1/4 inch ones at lower margin near the centre and a 1/2 x 3/4 inch one at the right-hand margin near the centre. These were inpainted with pigment in normal butyl methacrylate-xylene medium. Final protective treatment consisted of three applications of the same acrylic polymer; this was done by means of spraying.

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