Stradbroke Tithe map
Practical conservation was requested for the only copy of the Stradbroke tithe map in Suffolk, FC83/C1/13.
The map was drawn in carbon ink with watercolour highlights onto 4 sheets of cartridge paper. At some point since 1841 the map had suffered water damage causing staining and mould spots on the left. The paper sheets had also started to come apart, tears had developed and some areas had separated from the cloth backing.
During the 20th century additional damage was done through re-attaching the paper and cloth with double-sided tape. The tape had since dried out and the layers separated again; the adhesive had ‘cross-linked’ and turned brown so becoming difficult to remove and staining the paper and cloth.
Tests were made with a detached fragment to check that water washing would be safe and that all ink and watercolours were fast. The cloth lining was readily removed and tests done with four types of organic solvents to see if the residues of the self-adhesive tape could be easily removed, but unfortunately not. An oversize bath made in-house from waste cardboard and plastic sheet was used to wash the map; during the treatment the map separated into its four sheets. An additional wash with alkaline water and steam on the vacuum table was tried to see if the staining could be reduced. Alkaline residue was applied by spraying at various stages with calcium bicarbonate solution.
Next the four parts of the map were re-adhered; a gelatine adhesive of high bloom strength was used as this way the repairs would be less likely to separate when the map was re-dampened for lining. Temporary repairs were also made. A lining was then applied overall on the reverse to secure the map together and strengthen it. For this a considerably diluted wheat starch paste and a lightweight Japanese paper was used to ensure the map would remain as flexible as possible when finished.
After lining the map was turned over and repairs were made to the front including replacing any temporary facing tissues with permanent ones and infilling gaps in the sheet. Then the map was placed between woollen blankets and boards for drying.
Final flattening was carried out by restraint drying. The map was re-humidified and the edges of the map secured using the generous margin of lining paper applied to the map. As the map dried and shrunk back, it flattened out (fig. 4).