Treatment trials continued… (part III)

RESULTS – PEGGING

Before

Peg drying

After

The peg method was quite successful in reducing the planar distortion on the fully humidified sample. The pins were put straight through the ends of the pegs, meaning the parchment was held very taught with not much room for movement. If using this method on the Great Parchment Book, which is much more fragile, we would want to allow for more movement to prevent tearing. Therefore elastic bands would be attached to the pegs and the pins put through these to allow for more flexibility.

Close-up before

Close-up after

Treatment trials continued… (part II)

RESULTS – SUCTION TABLE

Before

Suction table drying

After

It was found that with both local and complete humidification, suction table drying was not appropriate. It did flatten out the sheet, but pulled smaller creases in more deeply. This method would be more effective on items that were less badly damaged, without shrunken areas, and that could be humidified to a greater extent.

Close-up before

Close-up after

Treatment trials continued…

19^th-century, artificially damaged parchment

A large manuscript, parchment document (not part of the LMA collections) was cut down into 16 small rectangles (180 x 140mm), which were then folded and sewn together to make a replica book. Successful shrinking was achieved through baking the book in a conventional oven and introducing moisture at regular intervals. The temperature was 200°C, and the book was left in the oven for 20 minutes with mill board clamped around it, then for another 10 with no mill board. The best shrinking was achieved by spraying the pages with water whilst it was in the oven.

The book was dis-bound and six folios chosen which seemed to have damage similar to that seen on the Great Parchment Book. Local humidification and full humidification combined with peg drying, suction drying and magnet drying was tested on the sheets. The results for those that were fully humidified can be seen below.

Results – magnets

Before

Magnet drying

After

This method was very successful, in terms of reducing the planar distortions. The only concern was that it might damage flaky media, and so an extra barrier, between the magnets and parchment might be needed. This method would be very good for badly torn sheets with areas too fragile to withstand having a clip or peg attached.

Close-up before

Close-up after

Treatment trials

Creased new parchment

Twelve samples of new parchment, which had been scrunched up and creases folded in, were tested to compare plain water against a water/ethanol solution, local humidification against full humidification, and different tension controlled drying methods (suction table, pegging out and magnets).

The three drying techniques:

1.	For the suction table method, samples were placed onto the suction table, with thick blotter underneath, and the creases gradually eased out.
2.	For the pegging method, plastic clips (with rubber and thick non-woven polyester between their jaws) were attached to the edges of the samples, and then put under tension and pinned in place on a soft board.
3.	For the magnet method, a metal sheet was covered in thick non-woven polyester, the samples placed on top, then small magnets covered in felt arranged on top to hold them flat.

Results

Humidification

In comparing the use of water and a water/ethanol solution to humidify the samples, it was found that there was little difference. After 1.5 hours, all samples were equally soft and ready for drying. The only main difference was that the samples that had been fully humidified with just water tended to curl up. Also with these samples it was difficult to see much difference between samples that had been partially humidified and those that had been fully humidified.

Tension drying

All the tension drying methods were quite successful with all the samples, which was to be expected for new parchment. With the magnets, difficulties might occur when applying the magnets to older, distorted samples with wavy edges if the parchment was only locally humidified. In this instance the edges would be quite hard and so susceptible to damage from the pressure of the magnets. This would also be a problem with the pegging out method too. The next stage will be to test these tension drying methods on samples of distorted parchment to see how appropriate they will be for use on the Great Parchment Book.

Deciding on treatments to trial for potential use

When deciding on potential treatments it is important to consider the main aims and outcomes that are sought.

For this project, these are:

To remove creases so that hidden text is visible and can be photographed

To consolidate flaky media

To repackage sheets for safe storage

To use techniques that are ethical and involve minimal intervention

Solvents for humidification

To achieve the first goal, humidification will be necessary and so we have to decide which solvents will be used for this. The main ones in use are water and water/ethanol solutions which work by the vapours penetrating between the fibres and improving hydration. Latest research findings suggest that any use of either can have a detrimental effect on parchment fibres, but the extent of this is dependent on the type of fibre and its condition. Water and a water/ethanol solution will therefore be tested on samples for their effectiveness as humidification agents.

Amount of humidification necessary

Minimal intervention is critical and so it should be tested to see if just partial humidification of the worst areas is adequate for opening creases, or if full humidification is required. For partial humidification, the samples will be put in a damp blotter/Gore-Tex sandwich, interleaved with polyester to protect areas that are not to be humidified. The samples that are to be fully humidified will be placed on top of damp blotter and Gore-Tex in a covered tray.

Methods for tension drying

Magnets

The item is pinned out onto a metal sheet with magnets placed on the surface. This is an appropriate option for the GPB as it has pages with very torn, fragile edges. However, it is important to be aware of the strength of the magnets being used. Also, they can be quite brittle and can leave marks on parchment, so should be wrapped in a protective material such as felt or thick non-woven polyester.

Pegging out

Pegs (or bull dog clips) are attached to the item edges and then tensioned out with pins. This method is appropriate for some of the less fragile pages of the GPB as the pegs can cause further damage to fragile edges.

Suction table

The item is held flat on the table while it dries. This could be an option, but might not be very effective on parchment that has areas that are very distorted and stiff, which the GPB has, as it relies on good contact with the table to allow flattening.

Pressing under boards

The item is placed under boards with weight on top. Given the amount of planar distortion in the GPB, this method would be totally inappropriate – creases would be pushed further into the parchment rather than pulled out. Also, problems have been seen in the past with this method causing the parchment to become transparent.

The next three posts will give details of trials to be carried out for humidification and crease reduction on three types of parchment. The first type is deliberately creased pieces of new parchment; the second is 19th century parchment, which will be deliberately heat damaged to replicate that seen on the GPB; the third is 17th century parchment with old heat damage caused by fire.