Museum Conservation staff describe the later phases of conservation of the Faddan More Psalter
The book is lying open on its original cover, a limp tanned leather structure with a fore edge flap to which are attached 3 large ‘buttons’. The binding has generated particular interest as a unique example of an early binding style that has not otherwise survived in Western Europe from this date.
The condition of the folios, which early tests showed it was possible to separate while wet, varied a great deal. Survival can vary enormously within a single folio and between adjacent pages, presumably depending on such factors as local conditions in the bog, treatment used in preparing the vellum, the nature of the hide cover and the area of the animal that it has been taken from. Condition varied from surprisingly good, with a ‘natural’ vellum colour and full legibility, to areas where the inks had partially tanned the surface directly below where they were applied, but the surrounding vellum had become gelatinous. Areas were also found where the letters have survived but the vellum matrix of the pages has been lost leaving the letters free to float around with only slight encouragement. There are large areas (60%+) of complete loss. The cover of the book was in good condition and, though ripped by the digger in places, appears to be complete.
It became apparent, as the manuscript was examined and its importance assessed, that a complex conservation project was required, with systematic recording and dismantling in order to extract as much information as possible about it as treatment proceeded. A project was initiated to carry out this process with a high level steering group from the National Museum of Ireland and Trinity College Library, with specialists in different aspects of the work sought for consultation as material related to their fields became available.
Overview of the Approach taken to the Conservation
It was obvious from the outset that the book presented major conservation challenges, straddling as it does, the fields of book and vellum conservation and archaeological conservation. Archaeological survival of vellum is extremely rare (we have only been able to find one previous instance) and we have not been able to find any record of a previous discovery of this nature.
The first task in the programme of conservation was one of consultation. We could not find any previous discoveries of such a find, so we consulted widely in the fields of both archaeological and book conservation, getting people’s reactions to the find, and the approaches that they would undertake if faced with it. We received a quite surprising number of different ideas with regard to
approach. Unfortunately this also led to a situation where we have received conflicting advice from a number of highly regarded conservators and have had to act on the basis of experimentation. The range of advice was very wide with that received from the book and archaeological conservation fields hugely varying at times. We have also heard of an initial publication of photographs that was produced of the Psalter, being left in a Conservation Department tea-room as a horror story!
At this point in the process, the Conservation Department of the National Museum of Ireland had been consulting very closely with the Conservation Department of Trinity Library, who holds 7 of the 10-pre 1000AD, Irish books still remaining in Ireland. We arranged for John Gillis, a Senior Conservator of books and manuscripts to be seconded to the Conservation Department of the National Museum, and it is this combination of experience -archaeological conservators from the National Museum working with a book conservator from Trinity College Library, who are conserving the Psalter. We are immensely grateful to Trinity College Library and their Conservation Department for agreeing to this arrangement and for the level of support that they have given.
An overall approach was agreed for the conservation element of the project with the following structure.
Phase 1
All investigations of the book that could be undertaken in a non-destructive manner would be carried out, and the object recorded in its ‘as found’ form in as many different ways as possible. This eventually included photography, drawing, MRI scanning (unsuccessful), multi spectral imaging (unsuccessful) and High Definition filming including close ups. CT scanning and X-ray were ruled out on the basis of reports of X-rays accelerating vellum degradation. Meanwhile tiny samples of the vellum were taken for degradation analysis and bookbinding specialists were brought in to analyse and record what structure in the binding was visible.
Phase 2
While phase 1 was occurring, samples of historic (18th century) parchment were taken, waterlogged and put under pressure for a period of 2 weeks. These samples, though by no means the same as the waterlogged archaeological vellum, were used for experimentation to establish the comparative effectiveness of the various drying techniques that had been suggested to us.
As a basic principal, it was agreed that no chemical be added to the vellum that would remain after the completion of the drying process. This principal was established primarily because of concern over the possible long-term effects of chemicals such as polyethylene glycol and glycerol on the inks and pigments present in the manuscript, and unfortunately ruled out some possible archaeological conservation techniques.
The following drying techniques were eventually tested:
- Air-drying
- Freeze-drying
- Air-drying on a vacuum table
- Air-drying under blottings and glass weights
- Drying between blottings using a ‘vacuum packing’ system
All of the drying techniques above were tried from water, but all the techniques given above with the exception of freeze drying were also tried, drying from various solvents, to establish if shrinkage could be reduced by reducing the surface tension of the liquid being removed. Solvents tested included ethanol, acetone and an acetone/ water solution.
A summary of the results is as follows:
Please note that these are broad statements regarding accurately measured and carefully controlled experiments. The statements included here are intended to give an idea of the approach taken, but the experiments will be written up in full elsewhere:
Drying from Water
Air-drying: (this really acted as a control method and was not expected to be considered as a viable method of treating the manuscript)
Very distorted. Loss of flexibility. Becoming translucent in places, leaving a blotchy appearance. 5% shrinkage
Freeze-drying
No distortion. Opacity maintained, but sample "pulped up” with a noticeable increase in thickness. Loss of natural pigmentation on hair side, becoming almost white, surface now "spongy”. 3.5% shrinkage
Air-drying on a vacuum table
Vacuum struggled to hold the samples in position. Translucent in places. 5% shrinkage
Air-drying under blottings and glass weights
Considerable colour changes in some samples with slight translucency in the sample dried through water. 3.5% shrinkage through water
Drying between blottings using a ‘vacuum packing’ system
No distortion throughout all samples, sample dried through water became very translucent. 1.5% shrinkage.
Effects of solvents
Solvents were tried in conjunction with each of the drying processes (except freeze drying)
Ethanol
Generally reduced shrinkage effects, compared to water and gave a good ‘visual’ result. Samples that became opaque when dried from water, did not when dried from ethanol
Acetone
Drying was so rapid as to be impossible to control, and the dried parchment had a ‘horny’ feel.
Acetone 80% Water 20%. The parchment was unstable in the solvent and pieces began to break off the surface during impregnation.
After further trials using the best performers from above and taking into consideration other working aspects of each method, the technique of vacuum pack drying between blottings, from ethanol was selected as the technique most likely to give good results when drying the Psalter. The technique involves the replacement of the water in the vellum by ethanol, by immersion in ethanol for 48 hours, changing solution half way through. The ethanol soaked vellum is then placed between layers of fine ‘bondina’ and then between 100% cotton blotting paper. This is then placed within a vacuum packing bag and put in the vacuum packing machine. The vacuum causes the ethanol to diffuse from the vellum into the surrounding blottings, while the even pressure of the blottings held in place by the vacuum, controls shrinkage. It is sometimes necessary to change blottings once during the process, which takes about 48 hours.
Phase 3
After the test pieces, the technique was tried on a small stray fragment of the Psalter and was found to be successful (after solubility tests for the inks). It was then tried on larger fragments, and eventually large pieces, again with remarkable success. Shrinkage of substantial pages of the Psalter is controlled and is consistently around 2% to 5%. This should be compared to a small and out of context fragment (with no text), which displayed approx. 75% shrinkage and massive distortion when air-dried.
The Psalter is currently being kept refrigerated and is brought out of storage solely for the removal of pieces to be treated. Treatment involves the removal of substantial pieces - generally the remains of entire gatherings, but the book itself and the way it lies dictate the precise nature of the pieces selected. A piece is identified, carefully recorded and lifted from the book by means of hand tools, some fabricated as required, bondina and silicon mylar - gently inserted as the pages and fragments are teased apart.
The piece is then separated out, using the same techniques into its bifolia, and is gently cleaned with suitable instruments, deionised water and ethanol. It is again recorded, often by a tracing at this stage. Each fragment is sandwiched between layers of bondina during the process to facilitate handling. When cleaned, it is dried using the technique outlined above.
During the process of dismantling and conserving the book, new discoveries are continuously being made as new pages are revealed, analyses undertaken, and as details of the binding structure become clearer. These are making this a particularly exciting project to participate in.
The project is very much a team effort and we are grateful to everyone who has contributed to it with their time and to the numerous members of the conservation community whom we have spoken to and who have been so generous with their advice.
By John Gillis and Anthony Read.