# Iron Gall Ink > Continuing my series on digitising Vatican manuscripts: how iron gall ink corrodes paper from within and threatens texts by Leonardo da Vinci and Bach. - Canonical page: https://shorin.me/en/blog/2024/06/chernila/ - Page language: English - Published: 2024-06-03 - Tags: BibliotecaApostolicaVaticana, Preservation, Library - Russian version: https://shorin.me/blog/2024/06/chernila/index.md I’m continuing my series on the challenges faced by Vatican Library staff when digitising different works. If you’ve only just joined me, here is the previous [post](https://shorin.me/en/blog/2024/05/lightning/index.md) (you’ll find a link to the one before it there, and so on until you’ve followed the entire chain). Another challenge in preserving books is the fact that iron gall ink has been used to create manuscripts since the days of the Roman Empire. This vivid black ink, with its velvety tone, is relatively easy to make. It penetrates deep into the paper and bonds firmly with the cellulose fibres. The great variety of surviving recipes makes it difficult to study. What is particularly interesting about most iron gall ink recipes is that their main ingredient is an oak gall, or gallnut – a spherical abnormal growth found mainly on oak leaves and young shoots. Logwood, indigo and soot were used as colouring agents. From the mid-19th century, acids were added so that the ink could be made as a solution rather than a suspension – first hydrochloric or sulphuric acid, then acetic or tartaric acid. Over time, the ink turns brownish-black, brown or dark brown. The acid it contains damages the cellulose, destroying the paper until the areas bearing lines of text fall away (see the photos). I have already written about how destructive the acid present in [cellulose](https://shorin.me/en/blog/2024/05/book-neutralization/index.md) can be. Now imagine that the ink itself also contains components that only accelerate oxidation. The very nature of iron gall ink therefore makes the long-term preservation of documents written with it impossible. Damage occurs faster or more slowly depending on the proportions of the ingredients and the conditions in which the documents are stored. Restoring such documents is extraordinarily difficult because there are so many recipes for iron gall ink, and each requires its own approach to neutralising acidity. Add the different recipes for producing shades of colour and the different papermaking techniques, and the number of possible combinations becomes enormous. And a great many manuscripts were written with this ink – Leonardo da Vinci’s notebooks, for example, and musical works by J. S. Bach. Sadly, we don’t think several steps ahead 😞 … ## Media ## Original posts - LinkedIn: