THE air is heady with the smell of cheap wine. I’m down on my knees smashing a pile of “gall nuts” into dust with a hammer. There’s a heap of green “cave scrapings” and tree sap by my side. But this isn’t a witches’ coven and I’m not casting spells. It’s the British Library, and I’m making ink.
The recipe we’re using, ripped from the pages of a how-to book from the 1500s, is remarkably simple, and in about 20 minutes a cluster of wannabe medievalists and I have a dozen pots of “iron gall” ink ready for writing with. Despite the bizarre ingredients, it all seems as innocent and harmless as a kid’s craft fair. You’d never suspect that the blue-black liquid pouring from our hands has caused so much pain and anguish.
Anguish in the world of modern librarians, that is. Leave this ink on paper for a few centuries, and it will literally eat its way through the page. Right now, in the heart of every archive, reams and reams of paper are falling to bits. The most popular ink for almost a thousand years is rusting its way through wedding certificates, medieval poems and history books. It’s making spiderweb cracks that will eventually crumble the American Constitution, rip Bach’s manuscripts to shreds, and turn Rembrandt’s sketches into a mess of puzzle pieces. Open an old book and disconnected letters can fall into your lap, the paper a lace doily with a mass of sentence-shaped holes.
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The scale of the decay is a disaster. But there is hope. Han Neevel and Birgit Reissland, a chemist and a conservator from the Netherlands Institute for Cultural Heritage in Amsterdam, have come to the British Library to teach a lab stuffed with conservators how to stop the rot in its tracks. Neevel and Reissland have developed a chemical solution that promises to keep history going a little longer. Already it has some thanking their lucky stars. “It’s the only thing that seems to work,” says David Jacobs, a senior conservator at the British Library.
Neevel and Reissland’s first mission is to get us to understand the ink – which is why we’re down on our knees making the stuff. The spiky, green “gall nuts” we’re pulverising are the remains of an oak tree’s inflammatory response to a wasp sting. Gall wasps inject their eggs into the tree’s buds, and their larvae grow in this odd cankerous growth. Some of the galls on our table today have tiny drill holes where the larvae have corkscrewed their way out. The ones without holes are considered to be of higher quality, since the dead grubs inside contain even more tannins, the chemicals these nuts are harvested for. In medieval times, Neevel tells us, scoundrels would fill up the holes in their catch so they could sell the nuts at a higher price.
We throw our nut powder into heated white wine, which turns a murky brown. The warm alcohol starts to extract the tannins, which break down and leak gallic acid into the mix. Next we smash up amber-coloured glassy chunks of gum arabic, which thickens up the ink. Finally we pound up green vitriol, or iron sulphate, a green crystalline powder that was traditionally scraped off the stalagmites of a cave or the walls of a mine. We’re not obsessive about authenticity, though: ours was bought from a catalogue, and we’re mixing it in with a glass rod instead of the “wooden sticke” we’re supposed to use (see “A booke of secrets, 1596”). The wine suddenly goes from brown to inky blue. The black magic, as Neevel calls it, has begun.
People have known since antiquity that these ingredients would produce this colour. Loggers noticed that oak trees chopped down with an iron axe would turn black at the stump, and some ancient texts even describe a “cure” for baldness that calls for a close shave with a rusty razor followed by a paint job with tannins. The colour comes from a blue-black precipitate of iron pyrogallate, formed when gallic acid, iron sulphate, oxygen and water react together. In the ink, the reaction goes on producing the precipitate for a long time because most of the gallic acid stays dissolved and will soak well into paper when used. Only then will it react with the air and turn black. When we write with our iron-gall ink, we watch our names darken on the page.
This habit of the ink to “bite” into the page is why iron gall became so popular by the 12th century. Unlike carbon-based inks, which leave powdered charcoal sitting loosely on top of the paper and smudge instantly in the wet, you can’t wash iron gall off, making it the best way to stop people from mucking about with official documents. But by favouring an ink that was permanent, in the short term at least, those scribes created a monster that would wreak a slow havoc on everything – from love letters to grocery lists – that we are seeking to preserve.
It’s not a new problem: scholars started to notice that iron-gall documents weren’t faring too well after just a few hundred years. At first they thought the problem was acid. One of the by-products of the gallic acid reaction is sulphuric acid, which can hydrolyse cellulose, effectively breaking up paper into crumbly bits of sugar. Conservators struggled to find ways to de-acidify documents by bathing them in bases like barium hydroxide or magnesium bicarbonate, which act as a chemical buffer and neutralise the acid in the paper even as the chemical reactions keep producing it over the years.
But the acid theory didn’t explain why there was such a huge range in the state of old documents. While some crumbled, others were as solid as the day they were made. The answer, as conservators finally established in the 1980s, is that the iron is actually doing the most harm. Free iron lurking in the ink reacts with air to form oxygen radicals – single molecules of oxygen with a lone electron hungry to react with anything it touches. That initiates a chain reaction that also breaks cellulose down into smaller molecules, yellowing the paper and making it brittle. The more iron sulphate an ink maker threw into his mix, the faster the paper now disintegrates.
Neevel’s solution is tailor-made to beat that problem. His inspiration came when he stumbled across a food researcher’s work on a natural antioxidant found in seeds that is now used to treat colon cancer. This chemical, called phytate, preferentially reacts with molecules that would otherwise react with oxygen in the air. That stops free radicals from being formed, and chokes off the kinds of destructive reactions that can rust nails or make our bodies age. Maybe, thought Neevel, phytate would stop paper from oxidising too.
Ironed out
Indeed it did. Neevel found that phytate rapidly attached itself to free iron in the ink, sucking it out of the page and stopping the first step of the radical reactions. Unlike most iron salts, these complexes are white, and camouflage nicely on a white page. “It’s a very elegant method. It doesn’t make a coloured solution itself, it doesn’t attack the ink itself – it has a lot going for it,” says Elmer Eusman, senior paper conservator for the US Library of Congress in Washington DC.
Use calcium phytate followed by a basic bath of calcium bicarbonate, and you can solve the acidity problem too, says Neevel. A quick dip, and a document should be preserved for centuries more – hopefully forever.
Archivists are getting excited. “So far we can’t see any side effects. It’s the first breakthrough in this area for years,” says Jana Kolar, chemist and head of the only EU-funded project on stabilising gall inks, based in the National and University Library in Slovenia.
But the method still isn’t perfect. Phytate is organic, and can be a tasty meal for mould if the books are stored in damp dungeons. And since the whole treatment is in water any water-soluble inks on the page, such as carbon-based inks, will wash away. Not forgetting that a really delicate document will fall apart if you do anything so drastic as washing it.
Neevel is working on a way to get water out of his system, perhaps by using alcohol instead, which should eliminate most of those problems. And others are hot on the trail of alternative methods. Kolar is pursuing another antioxidant that can deal with both iron and other metals in the ink that might catalyse ageing. The project is scheduled to finish in three years, but a deal with a private company prevents her from saying more about what it is or how it will work. Other groups are keen on simply submerging documents in boiling water, which seems to get out most of the iron and the acid, cleans the dirt away, and has the bonus of rehydrating the paper and making it more flexible.
“The first reactions from conservators is Ôgasp – what are you doing?'” says Julie Biggs, formerly the senior paper conservator for the Folger Shakespeare Library in Washington DC and now a freelance conservator. Going anywhere near boiling water seems like a brutally harsh treatment for such flimsy sheets of ancient paper. But research shows it works. Unlike phytate, though, it doesn’t lock up iron for good. The ink can continue to spit out free iron over the years, meaning you’d have to keep washing it.
Despite all the research, it will probably take years for anyone to adopt a radically new treatment. “Conservators are conservative,” laughs Biggs. And there’s good reason to be cautious. Many “protective” procedures have turned out to be hugely problematic. It’s easy to see why anyone would be hesitant, Eusman says. “A lot of the work we do is undoing previous efforts. At the beginning of the 20th century we had no idea what we were doing.”
Conservators used to focus on propping up the physical structure of a piece of paper – for example, gluing scaffolding to it – instead of treating the source of the problem. Bits of silk that were stuck onto paper in the early 1900s often made things worse, since the silk turned acidic over the years and the watery glues helped to spread free iron around the entire page. Reissland remembers when a team once systematically erased an entire book by washing the pages, not realising that the ink was unusually soluble. And some of Bach’s manuscripts were recently given a high-tech treatment where every page was split in two and a support stuck in the middle.
With the foreign material invading it like a disease, some say the documents have been ruined – all in the attempt to save them. “It’s a bit like leaving the facade of a famous building but completely ripping out the inside,” says Reissland. Even de-acidification schemes already in use, like commercial products of magnesium salts, can cause more yellowing of the page and ink discoloration than if nothing was done at all, according to Neevel. At the extreme end of caution, some say the best idea is to stick documents in an air-free box in sub-zero darkness, leave them undisturbed and cross your fingers; maybe it’s better to do nothing at all than to make a horrible mistake.
You might ask why they don’t just photograph the lot and forget about it. But an enormous amount of precious information about these documents would be lost this way: the thickness of the paper, the feel of it, the traces of other inks below the visible, the number of inks used and the order things were written, and innumerable other chemical hints that lie hidden on the pages. Newton’s notebooks have drips of chemicals on the page like splatters of sauce in a cookbook – information that would be forever lost in a photo. But, perhaps less obviously, photographs are harder to preserve than the paper documents, most lasting no more than a couple of centuries. The same goes for digital reproductions. If you can’t get a computer today to read a disc from 20 years ago, how on earth do you hope to preserve something for millennia? Despite its problems, pen and paper is still the king of long-term storage.
If Neevel’s phytate treatment is the answer to the ravages of iron gall, then it might be the way to turn long-term storage into permanent. Neevel has been working hard through conferences, papers and workshops to spread the word about phytate, and institutions around the world are starting their own investigations to check it out. At the Library of Congress, Eusman says he’d be more than happy to find better ways to keep documents there in pristine condition. “One of our divisions is completely overloaded with documents in iron gall. They’re not all in bad shape, but they’re a potential threat. You see these things rotting away and you feel you can’t wait 10 years.”
But Eusman still has his reservations, because phytate hasn’t yet been tested by time. “You don’t know what’s going to happen after you treat it,” he says. How can you know what’s going to happen to a document in a thousand years? To compare all these treatments, researchers put paper through “artificial ageing” tests, cranking the temperature up and down in quick succession, altering the humidity and flashing light at it. It definitely stresses the paper, but does it really “age” it? And if so, by how much? No one really knows. At the Library of Congress, they’re working through those tests and others to compare Neevel’s method with their current de-acidification schemes. So far, the phytate treatment looks promising. But ultimately the only way to really know what will happen is to wait a thousand years and see. By then, of course, it really will be too late.
A booke of secrets, 1596
Create the same as in this treatise you shal read. To make inke to write upon paper. Take a quart of strong wine, put it into a new pot, and set it on a soft fire till it be hote, but let it not seeth, then put into it foure ounces of gauls, two ounces and a half of gum Arabike, and two ounces of vitriall, al beaten into smal pouder, and sifted through a sive, stirre it with a wooden sticke, and it will be good inke.