In a previous blog, our volunteer Clare discussed working on the ‘grade 2’ railway plans, and explained how the conservation grading system works. Here, Jenny, our Conservator, takes us through what is required for those plans graded 3 and 4, those with significant damage or active deterioration.
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Of the original 132 railway plans, there were 52 with surface dirt, multiple tears and areas of significant loss were allocated a conservation grade 3, and three plans were given a grade 4; signifying they were actively deteriorating and required immediate attention before further loss of information occurred. The following are typical examples of these types of plans and a description of how we repair them.
Cleaning
The first course of action is to clean the plan. We do this using a soft goat hair brush and a latex sponge to remove more substantial deposits. The sponge can be abrasive, so it is not used on fragile paper that has become weak from mould damage.
Once clean, the sewing is cut to enable access to each separate sheet and aid the conservation process.
Lining
Japanese repair paper, which comes in many thicknesses and colours, was chosen to match the paper from the plan. Unlike the grade 2 plans where small repairs were made around tears, for plans made of wood pulp or transparent paper that will be accessed regularly, which are particularly thin and fragile and tear very easily when handled, it is preferable to line the whole sheet with Japanese paper.
The pages are lightly humidified to relax the paper fibres and are then placed onto our suction table. The table has a perforated top and air is drawn through the holes, holding the plan down and allowing small pieces of detached paper to be held in place during repair.
A piece of Japanese paper is cut larger than the plan and is placed onto a sheet of plastic. Thin wheat starch paste is brushed carefully onto the Japanese paper. The adhesives we use are easily reversible if the repair should need removing in the future, but also have great aging properties and do not yellow over time.
Using the sheet of plastic as support, the Japanese paper is laid over the plan. The plastic sheet is removed, leaving the Japanese paper adhered to the reverse of the plan, and drying is aided with a cool hairdryer. When dry to the touch, the plans are placed between blotters and left under weights overnight to ensure they are completely dry.
Housing
The excess Japanese paper is trimmed and the repaired sheets are sewn back together, following the same sewing structure as the original. The repaired plans are then housed within archival portfolios and stored flat in our repositories, ready for a researcher to request them.
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This is part six of a seven part series of blogs on the work we are doing to conserve the railway plans.
Part 1: Getting the Records Back on Track
Part 2: The Importance of the Railway Plans and Sections
Part 3: The Challenges of the Railway Plans