19th century treatments of palimpsests with chemicals

The British Library assigns its Syriac manuscripts to the “Asian and African Studies” department.  The people there are far easier to deal with than the people in Western Manuscripts.  They also run a blog which from time to time contains frankly wonderful material.

One such post was made back in September 2013, and I have written about it before.  It’s titled Some Syriac Manichean Treasures in the British Library, by Ursula Sims-Williams, and includes a picture of a page from BL Additional 12150:

Final page of Titus of Bostra, Against the Manichaeans. BL Add.12150, f.156r. Ms made in 411 AD!
Final page of Titus of Bostra, Against the Manichaeans. BL Add.12150, f.156r. Ms made in 411 AD!

What caught my eye today was a postscript by Christina Duffy, which must have been added subsequently.  It concerns palimpsests, those manuscripts where, in ancient times, the text was washed off the parchment, and a new text written on top.  Sometimes the lower text was dimly visible, even so.

In the 19th century, scholars discovered that the under text could be made very clear by painting the page with “reagents” – chemicals, usually acids of one sort or another.  This allowed the under-text to be transcribed, but also frequently damaged the manuscript.  However what was done precisely, and why it worked, has never been clear to me.

Christina Duffy’s statement is the clearest explanation of the subject that I have ever seen, and I’m going to give it here, word for word.

Sadly the result of chemicals used to make indecipherable script legible is seen in many of our manuscripts here at the BL. While the treatments initially enhanced the faded text greatly it was only a matter of time before the entire passage was left in a much worse state!

In 1969 Restaurator reprinted a report of the St Gallen Conference on the Conservation of Manuscripts from 1898 which listed gallic acid, thiocyanate, ammonium sulphide, sodium sulphide, potassium ferrocyanide and tannin solution as chemicals used to recover text. Essentially the reagents were attempting to balance the ink formulation. By “reagent” we mean a substance or compound used to bring about a chemical reaction.

There is mention of the use of chemical reinforcements as early as the 17th century but it wasn’t until the 19th century when chemistry was more understood that lots of reactions were tried out. For iron-gall ink, a good stable black ink is formed by a black iron-gall ink complex. If the ink production for whatever reason is imperfect, ink can become illegible overtime i.e. fade. Imperfect ink is generally missing one of the essential compounds in the ink ingredient list (such as iron sulphide or gallic acid) so it makes sense that applying these missing chemicals will allow the reaction to take place and the text to become clear again! Which is what they did, but alas the aftermath was less pleasing!

The oldest known recipe for text recovery uses gallic acid. One article suggests making an extract of gall-nuts in white wine and wetting the missing text with a sponge to recover the text. However it isn’t mentioned that the gall-nut extract goes brown itself after a few years and wherever the liquid was applied turns dark brown so nothing is legible!

Other treatments include hepar suplhuris, toning letters blue by reacting iron ions with potassium hexacyanoferrates or placing the text briefly in hydrochloric acid. Some manuscripts treated in this way are now covered in blue dye and completely illegible…which is why using imaging techniques is a much better idea!

There is a good article explaining all this including the chemical formulas by Robert Fuchs, “The history of chemical reinforcement of texts in manuscripts – What should we do now?” in Care and Conservation of Manuscripts 7 (2003): 159–170.

I wonder if multi-spectral imaging would give us something, even now?

7 thoughts on “19th century treatments of palimpsests with chemicals

  1. Sickening. And honestly, they should have known that oak gall makes things brown. That is the whole point.

    But I agree that both texts are clearly still there, even if a bit flooded out. So it is a good thing that they have kept the ruined texts.

  2. When I studied some archaeology as part of my undergraduate History major (many a year ago, now), I had it impressed upon me that ‘excavation is destruction’, and that, where possible, it is preferable not to try to excavate too extensively but to leave something intact in situ for future archaeologists who are almost certain to have new technical advantages which will discover things that simply cannot yet be discovered.

    And, more recently, I talked with someone who restores paintings, and he told me he carefully documents everything he does, and everything done is very deliberately done so as to be reversible.

    If only our palaeographical forebears had been more circumspect and less ambitious!

  3. All sadly true. But I think we have to remember that every advance is made by taking risks and making mistakes. We stand on the shoulders of those who realised what was possible. The recovery of material from palimpsests starts in the 1820s, when people had very different attitudes.

  4. To be fair, a lot of folks back then operated under the fear that if you didn’t do stuff now, the stuff might not exist later to be played with. Estates and museums were subject to fire, damp, war, terrorism, etc. The same is true today, of course (except our climate control is better), but we are gambling on the long view.

  5. We do take a lot for granted. I wish, how I wish, that I had not got sick in 2010, 10 days before I was due to take a tour of Syria. I was sad; but it never occurred to me that much of what I wanted to see might not be there next time!

  6. Thankfully, the Islamist terrorists do not seem to have done as much damage in Palmyra as they might have done. I spent a memorable month in Syria in July 1991, shortly after the end of the Gulf War (Syria was one of the Coalition members back then), and have never seen anything quite as impressive as the ruins of Palmyra. With luck, much of what has been blown up has simply been knocked down, and can be put back together again. I don’t know how bad the damage has been at Hatra and Nimrud in Iraq. Two Christian monasteries (the Syrian Catholic monastery of Mar Behnam and the Chaldean monastery of Mar Eliya) have been knocked about too, and they have destroyed the Muslim shrine of Jonah (Nebi Yunas) in Mosul. The coffin containing the supposed remains of Jonah, which was presumably blown sky high along with the rest of the shrine, in fact used to enclose the corpse of the Nestorian patriarch Hnanisho I (died around 700 but body miraculously preserved and displayed around 1348 to admiring Christian crowds in Mosul). I am glad I took hundreds of photos of Roman antiquities and Christian churches in Syria back then …

  7. Once the fighting stops it will all get clearer, I think. But make copies of those pics! They’re now historically important!!

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