Restoration of Jacob Xavery's graphic work The Parable of the Labourers in the Vineyard

In 2005 the Laboratory for Scientific Restoration of Works of Graphic Art completed a unique restoration of Jacob Xaverius's (1736-1769) Parable of the Labourers in the Vineyard. This signed work was executed in 1768 and entered the funds of the State Hermitage in 1974 from the collection of the artist Nathan Altman.

The drawing was done on rag paper in a complex technique using watercolour, white and pastel chalks. It was glued entirely onto a primed canvas. Possibly the canvas was initially fixed to a stretcher and the drawing was kept like a painting on a canvas in a frame. Later it was taken off the stretcher and the edges of the canvas were cut unevenly; in the right and left parts - right down to the ends of the picture. The drawing came in for restoration with its surface heavily dirty and with accumulations of dirt and dust. Under the influence of the glue and its high acidity, the paper had become extremely pulpy and fragile. Even slight mechanical action would cause it to crumble and disintegrate. At the edges the dried out paper base partly peeled off the canvas. There were numerous small- and medium-sized losses of the paper base, while at the corners and edges of the sheet they were larger (up to 0.8 х 1.5 cm). There were many breaks and deep creases in various directions, as well as small criss-crossing fractures, scratches on the picture and significant wear and partial loss of the paint layer of the background and along the lines of breaks. The pigment was weakened and was flaking off on some fragments of the picture. All of this provided evidence of the need for serious restoration measures. The application of traditional methods was complicated by the high degree of destruction of the work, which required an individual approach to selection and application of one or another means of restoration.

The Restoration Commission took the decision to remove the work from the canvas insofar as the ground had dried out and the old and rigid darkened glues as well as the canvas's acidity (рН - 4.3) all encouraged further development of destructive processes in the paper base. In the process of restoration measures, it was essential to clean the base of dust and multi-layer soiling of the surface, to stabilize the paper base, to bring its pН into a neutral state, to strengthen the weak areas, glue together the tears and fill in losses of the base, as well as eliminate deformation.

In the process of restoration measures, the paper base of the drawing was freed of dust using a mild squirrel fur brush. The soiling of the surface was reduced. Then the drawing was separated from the canvas. This process was complicated by the presence of ground on the canvas and took a lengthy time. Carefully, with the help of a bamboo knife, while holding the work in place, literally working centimetre by centimetre, the restorer freed the paper from the canvas. In several places the dried ground separated more easily from the canvas than from the paper base, forming a solid unit with the fibres of the paper. The pieces of ground which remained in the fibres of the paper base initially were very carefully crumbled by the end of a sharp scalpel and then were removed grain by grain. The freed part of the surface was cleaned of the many layers of dirt of various kinds and also of old glue of animal origin using a compress moistened with a thick water solution of methylcellulose. The removal of the canvas made it possible to free the reverse side of the work of traces of old darkened glue and also to eliminate the yellowing of the paper base. Removal of the film of methylcellulose which remained on the surface of the paper and weakening of the yellow tint in the paper in each part was carried out with the help of micro-tampons moistened with distilled water and then squeezed out to a semi-dry state. This lengthy process had to be repeated many times. If there was excessive moisture, it was squeezed out using small pieces of filtre paper. Such an important operation as washing was done at the same time as another restoration process - removal of water soluble dirt of various kinds.

In order to preserve the integrity of the work, separate fragments were strengthened with small strips of fine restoration paper - forming a kind of "lock" both on the reverse and on the obverse side. The process of strengthening the damaged parts of the paper began with gluing together, using fine Japanese paper, the larger tears and creases with tears, and also with filling in losses at the corners and edges of the drawing. At the same time, when gluing underneath, they carefully eliminated the "locks" from the reverse side, and then from the obverse side as well. Losses of the base were filled in with paper of texture, thickness and colour similar to the original.

Bearing in mind the fragile condition of the paper base, the work was relined with very thin restoration paper which did not disturb the plasticity of the original paper. For this purpose, glue based on wheat starch was used. Then the work was levelled and allowed to dry between sheets of filtre paper and Chromersatz brand cardboard. The filled in losses were delicately tinted. The parts of the paint layer with flaking were strengthened using a 0.5% water solution of methylcellulose. During tinting the solution was drawn onto the brush together with the pigment and applied to the section being tinted.

After the cleaning and reduction of the overall yellowish cast of the paper base, blue pigment was revealed in the upper part and the colours in the foreground came out more bright, all of which made it possible to feel the depth of the spatial composition of the drawing better.

Once taken down off the oxidized canvas, the paper base of the work stabilized; its pH was brought near to neutral (5.8) and the deformations were eliminated. For a long time the drawing was kept under the observation of the restorer and curator. Now it has been set in a passe-partout of museum cardboard and is kept in the stock of the Department of Western European Art, continuing its life as a work of graphic art made on a paper base. The restoration was carried out by art restorer of the highest category Yelena Rudakas.

The Parable of the Labourers in the Vineyard
Jacob Xaverius
Before restoration
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The drawing in the process of restoration following separation of the paper from the canvas
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The reverse side of the drawing following separation from the canvas
Larger view

The Parable of the Labourers in the Vineyard
Jacob Xaverius
After restoration
Larger view