The Prize Papers is a vast collection of seized papers and goods from enemy ships captured by the British in wartime, (around 1652–1856). It is being digitised in partnership with Oldenburg University. Un-opened, sealed letters are often found within the Prize Papers collection.
Very few of the closed letters seized in these ship captures, perhaps as little as 5%, have identifying information on the outside – such as the name of the ship that carried them or information on their country of origin. This means that the only way to discover this important information is to open the letters and read them. As a digitisation conservator working on this project, this is what I was asked to do for 200 closed letters so that researchers could determine their provenance.
The closed letters I was asked to look at in HCA 32/111E could have come from either the Fort de Nantes, captured in 1747, or the Atrevida, captured in 1779. Photos were taken beforehand to document their appearance. The aim with any treatment to open these letters was to cause minimal alteration to their aesthetics.
The closed letters were held shut with seals. I identified three potential groups of seal materials: Shellac seals, brown wafer seals and, pink or red wafer seals. This blog focuses solely on the opening of the wafer seals. Letters with shellac seals were carefully cut open using a scalpel, preserving as much of the physical materiality of both the seal and the letter as possible.
I analysed the seals of four letters using ATR-FTIR spectroscopy. This is a sampling technique that uses the absorption of infrared light to analyse material properties. This test found that, regardless of seal colour, all the wafer seals were starch based.
Taking this into consideration, as well as the fact that most of these letters were written in iron gall ink and often had additional letters inside them, I decided the safest way to separate the starch wafer from the letter wrapper was to use an agar gel impregnated with an alpha amylase enzyme. Using a gel allowed me to keep the amount of moisture needed to open the letters to a minimum. This reduced the likelihood of the paper distorting during treatment or tidelines occurring and protected the iron gall ink from possible corrosion.
I experimented with different concentrations of the agar gel and alpha amylase enzyme to find a solution that caused as little visible change as possible. The colour and thickness of the seals affected how they reacted to the gel and how quickly they opened, so there were lots of factors to take into consideration.
By using this approach, I was able to open the letters without causing any physical damage, allowing them to be read safely.
Details about the letters can be found in Discovery, our online catalogue.
Read more about the Prize Papers Project