BLOG: Portrait of Sir John Hartopp returns to display following conservation treatment

Problems Identified

Examination revealed that the frame had become unstable over time. The bottom right mitred corner joint had failed and the corner block had detached, leaving the frame with significant movement. All four rebate pieces were loose, and the rebate opening had become too large to securely support the painting. The flexibility caused by the weakened corner joints had contributed to the painting slipping within the frame.

Additional issues included:

• A missing section of decorative moulding at the centre of the lower edge.
• Small losses to the gilded finish along the top moulding.
• Extensive flaking and loss of the ochre-painted finish on the reverse edges of the side mouldings.
• Splits in the rebate and areas of unstable paint on the outside edges.

Conserving the Frame

The frame first underwent careful surface cleaning. The detached corner block was re-adhered using Resin W wood glue, while all corner blocks were strengthened with small galvanised screws to improve their connection to the main frame. To provide additional support, metal L-brackets were installed at each corner, removing the flex that had developed over time.

The areas of flaking paint on the outside edges were consolidated and retouched with gouache, the splits in the rebate were glued with fish glue, and shallow support blocks were added to the lower corners and behind new hanging fittings to better accommodate the depth of the canvas.

Losses to the gilded surface were carefully retouched using gouache paints, while the missing section of ornament was recreated using Milliput™, shaped to match the original decoration and then gilded.

The original fixings were removed and replaced with a more secure system. A new gilded slip was fitted inside the rebate to reduce the opening size, ensuring the painting sat securely within the frame. Velvet ribbon was added to the rebate to protect the edges of the canvas, while new balsa wood spacers, brass mirror plates, and screws were used to secure the painting safely in place.

Conserving the Painting

The painting itself also benefited from careful treatment. Surface dirt was removed from the reverse of the canvas using a Wishab™ sponge, a soft brush and a low-suction vacuum, while the reverse of the stretcher was cleaned with a conservation smoke sponge.

The painted surface was then cleaned using saliva applied with cotton swabs, a well-established conservation technique that effectively removes accumulated dirt without harming original paint. Residues were removed using deionised water.

To improve the appearance of the painting, reduce the visibility of scratches and scuffs in the old varnish, and enhance colour saturation, the surface was spray varnished with a solution of Laropal® A81 varnish. Areas of previous restoration that had become visually distracting were also carefully retouched using dry pigments bound in Laropal® A81.

Back on Display

Following its conservation treatment completed in July 2026, the Portrait of Sir John Hartopp has been returned to display at Peterborough Museum & Art Gallery. The work is now structurally secure, visually improved, and protected for the future.

Visitors can once again enjoy this important portrait and its fascinating connections to both national and local history, ensuring that it remains part of the museum's collection for generations to come.