completed treatment

before treatment

after treatment

Original painting by Jan Hendrik Weissenbruch. Strandgezicht (Beach Sight). 1887. Oil on canvas. 72.8 x 102.9 cm. Source: Kunstmuseum, The Hague, Netherlands.

  • title Strandgezicht

    (this painting is a copy of Strandgezicht (1887)by Jan Hendrik Weissenbruch, currently on display at the Kunstmuseum, Den Haag)

    artist unknown

    date after 1887

    material oil on canvas

    dimensions 80 x 60 x 2 cm

    inventory number XN2084

    owner Rijksdienst voor het Cultureel Erfgoed

  • brittle canvas along tacking margins

    small holes in canvas

    losses of ground and paint layer

    discoloured retouches

    large areas of overpaint

    yellowed, uneven varnish layer

  • goal to address structural issues, a crucial undertaking aimed at preventing additional harm to both the paint layer and canvas, and to enhance the visual appeal by mitigating disruptions within the composition and restoring the vibrancy of colours

    1. varnish removal

    The varnish layer will be removed to enhance the readability of the composition and augment the colour brightness. Removal is imperative not only for aesthetic reasons but also to forestall the varnish from reaching an insoluble state.

    2. removal of retouches and overpaint

    The discoloured retouches will be removed. The overpaint in the clouds and along the horizon will be removed for the following reasons:

    • It covers ageing cracks and fillings applied during a previous treatment and is therefore not an addition by the artist

    • It covers a large part of the original paint layer, which is in a fairly good condition

    • It has deteriorated

    • It is visually disturbing

    • It can be removed safely

    • Removing the disturbing overpaint will restore the integrity of the painting as an intended Weissenbruch copy.

    For now, the decision has been made to leave the remaining overpaint in the beach, since it is not as disturbing and safe removal cannot be guaranteed because of the presence of impastos. This decision will be re-evaluated when the removal of the overpaint in the other areas is finalised. This decision was made in consultation with the RCE head conservator of paintings.

    3. intermediate varnish

    Applying an intermediate varnish will isolate the original paint layers from the retouches. This layer will also enhance the colour saturation of the paint, a crucial step for achieving a colour match between the retouches and the original.

    4. filling

    To establish a uniform surface for subsequent retouching, it is essential to address the losses by filling them. Given that the bare canvas is predominantly exposed in numerous areas, the utilization of a thermoplastic filling material is probable. This choice is made to ensure a more controlled and reversible filling process.

    5. retouches

    The fills will be retouched to restore unity in both colour and composition.

    6. canvas consolidation

    To prevent further detachment and damage of the canvas in the corners of the tacking margins during treatment, the loosely hanging canvas pieces will be consolidated.

    7. final varnish

    To protect the paint film from UV light and fluctuations in relative humidity, as well as to enhance colour saturation and establish a uniformly reflective surface, a final layer of varnish will be applied.

    8. backing board

    To safeguard the delicate canvas from physical forces, dirt, and/or humidity, a backing board will be applied to protect the reverse side of the painting.

    Thorough documentation of both the technical examination findings and the treatment outcomes will be meticulously carried out.

  • initial condition

    initial condition

  • during varnish removal

    during varnish removal

    using a Carbopol Ethomeen C25 gel with isopropanol

  • after varnish removal

    after varnish removal

  • presence overpaint

    mapping of the overpaint

    in red

  • overpaint removal: first stage

    overpaint removal: first stage

    mechanically removed with a scalpel

  • overpaint removal: second stage

    overpaint removal: second stage

  • after overpaint removal

    after overpaint removal

  • detail of fils

    after filling the paint losses

    using thermoplastic BEVA fillings

highlights

Using a Carbopol® Ethomeen® C25 gel with isopropanol to remove the aged and yellowed varnish layer

Carbopol Ethomeen C25 solvent gels can be a good solution for effectively removing the aged varnish from a painting. This gel, formed by the complex chemistry of Carbopol and the polar amine surfactant Ethomeen C25, enables controlled delivery of polar solvents like isopropanol to remove the aged varnish. The gel's controllable rheological properties and stable structure ensure prolonged contact with the varnish, optimizing the cleaning process.

After brushing the gel on the surface, while following the shapes of the composition, a sheet of a Melinex® polyester film was placed over the area to reduce solvent evaporation. After 3 minutes, the gel was removed with a cotton swab and the gel and varnish residues were removed with isopropanol.

Consolidation of fragile canvas along the tacking margins

To reinforce loosely hanging canvas pieces and fragile areas along the tacking margins, small patches were placed between the stretcher and the canvas. These patches consisted of unwoven polyester coated with Plextol B500 (which was allowed to dry). After shaping the patches to fit the designated areas, ethyl acetate was brushed onto the adhesive to activate it. The patches were then carefully positioned and light pressure was applied to ensure proper adhesion between the canvas and the stretcher.

1: lower right corner before patch application, 2: first stage patch application, 3: loose canvas piece adhered back in place onto the patch, 4: the result of canvas consolidation in the lower right corner.