The Conservation of Peter Small’s Pedigree

by Emma Skinner, Oxford Conservation Consortium

November 2022

Before Treatment

This large sixteenth-century genealogical table recently arrived at the Oxford Conservation Consortium’s studio for treatment. It provides the pedigree for Peter Small, who was elected as a Founder’s Kin Fellow of St John’s in 1597.[1] It was bound with a nineteenth-century printed list of Founder’s Kin Fellows, in an unassuming paper-covered binding. Descendants or relations of the Founder were given preferential treatment when applying to the college.

On examination, it was immediately clear to see the pedigree was in very poor condition which meant that it was listed as high priority for conservation by the librarian.  Patches of brown paper tape on the verso had been used to stabilise areas of damage, including tears and losses and covered large areas causing distortion to the paper. The tape appeared to be a glassine paper which would have originally been transparent but had discoloured with age.

The document was written in a single sixteenth-century secretary hand in black ink identified as iron-gall ink by its pattern of degradation. Iron-gall ink was typically made from tannin (usually extracted from oak galls), vitriol (iron sulphate), gum Arabic, and water. The two primary degradation mechanisms of iron-gall ink are oxidation and acid hydrolysis, both being autocatalytic which means they interact and increase the reaction rate of the other. Eventually the ink will effectively ‘burn through’ the paper underneath causing loss of the textual information and also of the substrate itself.

Iron gall ink degradation exhibits brown discolouration, haloing, and burn-through of the ink causing loss to the paper

The paper support was made of three separate pieces of handmade laid paper which had been folded in half vertically, twice. The brown paper repair patches on the verso were likely applied when the pedigree was put in boards, but they were crudely applied and had caused distortion to the paper support. Areas of text were difficult to read as a result, and where the ink corrosion was most severe were obscured entirely; leaving the repairs in place would have significantly inhibited my repair.

Treatment Overview

A condition report was written and before treatment photographs were taken to record the state of the genealogy on arrival to the conservation studio. This is an important part of our conservation documentation process and provides a vital record of changes to an object during conservation.

After discussion with the librarian about the different options for treatment, it was decided that the pedigree would be removed from the nineteenth-century binding, as it was not possible to unfold it fully and consult it safely in- situ and the repeated folding was causing damage to the object that was difficult to prevent. By removing the pedigree from the binding, which was a later housing method, it would be possible to make more effective repairs to the damaged areas and store the document flat. The pedigree had been secured within boards by a thick cream-coloured wove paper guard, adhered to the verso of the pedigree. To remove the document, the guard was cut and a thin strip was left adhered to the object.

The remnants of the paper guard which had been used to adhere the pedigree into the binding

Once removed, the pedigree could be fully unfolded and the severity of the iron-gall ink corrosion determined. A light box is an excellent tool when undertaking conservation work on a paper object as it illuminates the cracks and splits in the paper clearly, it was shocking to see the extent of the damage in the heavily inked areas.

The extent of iron-gall ink corrosion and damage to the paper can be seen easier using transmitted light

The brown tape was removed from the verso to facilitate more functional and accurate repair and stabilisation of these damaged areas, but it was vital that non-aqueous methods were used. As high levels of humidity (>70%) cause the migration of soluble components in the ink and accelerate the autocatalytic reaction, avoidance of excess moisture was of primary importance during treatment. Where the tape was brittle, it was removed mechanically with a spatula, applying heat with a tacking iron through a barrier layer proved the most successful method.

In order to minimise the risk of loss to the most vulnerable areas, small splints of Japanese kozo paper were adhered to the recto (avoiding inked areas) with a sieved gelatine adhesive prior to tape removal.  Kozo-fibre paper was used because it is long fibred, lightweight and translucent but very strong.

These splint repairs allowed the tape to be removed with ease using a Teflon folder, spatula and tweezers without damage to the paper support and without causing any loss to the paper or ink, with any fragments at risk of loss being held in place with the repair splints. One of the brown tape patches on the verso had a pencil inscription reading ‘Pedigree of Peter Smale Founder’s Kin Fellow 1597’. As this piece had textual information, and did not seem to be causing distortion to the paper, there was no reason to remove it and it was left in place. It also survives as evidence for the object’s history and its materiality.

Once repaired, I needed to think about its housing. Although the most vulnerable areas had been stabilised, it remained inherently fragile due to the risk of fracture and loss caused by the iron-gall ink corrosion.

As well as exposure to high humidity, handling is another risk factor to items displaying iron gall ink corrosion with the existing cracked and weakened areas of degradation being worsened through flexing, folding and abrasion to the substrate. Therefore a housing solution needed to be found whereby the object could be moved and the textual information accessed, without needing to handle the paper directly. The small amount of textual information on the verso of the pedigree posed a challenge, as repeatedly turning over an object of this size which is so fragile is problematic. A compromise was found by providing a high quality image of the verso kept in a polyester sleeve inside the original binding.

The pedigree was rehoused in a folder made of acid-free archival mount board The item rests on the backboard and is held in place by thin polypropylene straps adhered to the exterior of the folder with double-sided tape, covered with an archival Photokraft paper. There is a 15mm build-up of mount board around the edges of the backboard which prevents the folder from touching the pedigree, which does not lie flat. If it is ever exhibited the folder is designed to open back on itself to enable display, without needing to remove the pedigree from its bespoke housing. The binding will be housed with the pedigree. The poor condition and fragility of this object, alongside the complex chemical activity of the ink, made this a challenging treatment to undertake. Fortunately the brown paper patches were relatively easy to remove once it was found that the heated spatula facilitated mechanical removal with a spatula. The final result of the treatment is a more stable document that can be easily consulted and displayed with minimal handling. The pedigree is now digitised, which further increases access and aids close examination.

New housing solution – pedigree strapped into its mount board folder.

You can read more conservation blog posts on the Oxford Conservation Consortium’s website at Oxford Conservation Consortium – The Chantry Library.

[1] *Founders’ kin was a hereditary privilege at certain colleges of the University of Oxford whereby preference was given to applicants who were kin of, related to or descended from, the founder or founders of that college.

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