A Conservation perspective (from Kat Saunt)
Heritage Open Days 2021 theme was Edible England and as part of my conservation workshop tours on Saturday the 11th of September I was able to talk about how many of the materials I use to conserve archive documents could – at a push- be described as edible.
To repair damaged parchment I turn to adhesives and surface consolidants made from gelatine, or sometimes isinglass, also referred to as ‘fish glue’, which is made by cooking sturgeon’s bladder. To repair tears or fill holes I might use what is called goldbeaters skin, which is actually intestine membrane – basically sausage casing!
To repair paper I often use a substance called methyl cellulose which you can also find in the ingredients list of many foods, sometimes used as an egg-replacement. And the most commonly used substance in paper conservation is our indispensable hero ingredient – Japanese wheat-starch paste. A traditional adhesive simply made of wheat starch cooked in water.
After those examples of protein and carbohydrates, we also have vegetables represented by agar and funori seaweeds from which we can make a consolidant for flaking pigments. Agar is often used as a food ingredient.
So that’s the menu of “edible” ingredients we keep in the conservation workshop.
Although modern conservation science gives us a lot of indispensable techniques and materials to preserve historic documents, there is a benefit to using natural and traditional materials. Unlike more modern synthetic materials (which are often less stable) we know how these materials age and behave over centuries, and they are usually the same type of materials and even tools that were used when the document was created. Also, these traditional materials are also less hazardous and don’t require use of a fume cupboard or hard to recycle single-use personal protective equipment.
So that’s the menu of “edible” ingredients we keep in the conservation workshop. It’s not exactly Bakeoff but I hope that it’s an interesting insight into what it takes to conserve 800 years of historic documents.
By Kat Saunt