This hand-coloured print showing a plan of Epsom racecourse was prioritised for conservation due to its fragile and worsening condition and the risk of losing valuable information about the history of the course. The plan shows sections of the racecourse, and much of the information was obscured by a very dark varnish layer.
Condition before treatment
The plan was in extremely poor condition due to several factors:
- The paper is intrinsically acidic as it is a machine-made wood pulp paper. This means it becomes weaker over time due to the breakdown of the paper fibres
- The plan had been lined with linen using a starch paste. The paper had lifted from the linen in some areas, and information has been lost as fragments broke away
- The plan had at some point been stored in a damp environment and mould staining remained in some areas
- The plan had been attached to wooden poles using nails that had pierced the paper and caused further damage and rust staining, especially along the top edge
- The whole map had been coated in a heavy, glossy varnish which had darkened over time, obscuring the image underneath
Conservation treatment
The first step in conserving this plan was to remove the remaining wooden pole to prevent further damage when handling. The mould-stained linen backing was then carefully removed to allow the paper to be thoroughly surface cleaned on the front surface and the back. The document was supported on a sheet of woven polyester throughout this process to ensure any fragments were kept in position.
After surface cleaning, the next step was to remove the thick varnish layer. Tests were carried out with a variety of solvents to find the most effective choice. Once an effective solvent had been identified, work began to lift the varnish off the surface of the paper without damaging the inks and pigments underneath.
This was achieved by working in sections using a Japanese paper barrier and suspending the solvent in a gel to ensure the varnish was lifted off the surface and onto the Japanese paper barrier. The solvent gel was allowed time to work before peeling off the Japanese paper with the varnish layer attached … A bit like waxing off hair! It is very satisfying to see the image underneath as the dark varnish is removed.
Though there was some residual staining left by the varnish deep within the paper fibres, the image underneath was visible, and the information was accessible for the first time in many years.
Once as much of the varnish as possible had been removed, the plan was washed on a carrier, initially using a solvent solution to rinse out any remaining varnish residue. Once the water ran clear, the paper was deacidified using a mild alkaline solution.
After washing, the plan was lined on our back-lit light wall using a suitable Japanese paper lining. We use Japanese paper because of its purity. It is thin and flexible, but also very strong due to its long fibres.
Once lined, the plan was allowed to dry for several days before infilling the missing areas using a suitable handmade paper of a similar tone and thickness. This ensures stability and prevents weak areas where the original paper had been lost. In archives, we focus on conservation principles rather than restoration. This means that all repairs need to be visible and discernible from the original paper. They also need to be reversible, so only wheat starch paste is used as the adhesive. We also avoid bleaching paper fibres which is sometimes used in restoration to brighten the paper and remove staining, but this can accelerate deterioration over time.
Preservation
Once the plan and the infills are thoroughly dry, the plan can be lifted off the wall board, trimmed, and placed within an archival polyester sleeve for preservation. This wonderful plan will be stored in one of our plan chests in our environmentally controlled strongrooms for future generations to use and enjoy. If conservation work had not taken place, the plan would have gradually disintegrated and darkened until the information was lost forever.
Images
Select image to view a larger version.
- The Epsom Racecourse plan before conservation (reference 10697/1)
- Mould-stained linen removal
- Varnish after surface cleaning
- Varnish removal before and after
- The plan on the back-lit light wall
- The Epsom Racecourse plan after conservation