Struggling against the invisible

An intricate procedure for rescuing manuscripts

You can’t see it, smell it or feel it – but wherever there’s old paper, it’s often a problem: acidic content resulting from the industrial production of paper, which over the course of time can lead to yellowing and even complete disintegration.

The German Literature Archive (DLA) in Marbach, whose vast collections contain important literary sources dating back to the Enlightenment, employs a technically sophisticated process in the struggle against these harmful substances. Many people are familiar with the problem from their own bookshelves. The paper of a much-loved old book or their great-grandmother’s diary is getting steadily darker and increasingly unsightly, even threatening to fall apart. “What’s to blame for this,” explains Melanie Kubitza, who works in the Conservation department at DLA, “are the acids contained in industrially produced paper since the mid-19th century.” After many years, this can lead to yellowing and even cause the paper to disintegrate, and with it, whatever was printed or written on it.

Preserving precious originals

For Kubitza, a university-trained specialist in the restoration and conservation of written materials, graphics, and book illustrations, this is nothing short of tragic: even in the digital age, important historical documents in Marbach are at risk. Viewing a digital reproduction or a mere transcript simply can’t compare to the experience of looking at an actual letter that the poet Heinrich Heine wrote to his publisher.

An optimized process

In order to physically preserve Germany’s literary heritage, the DLA uses the Papersave process to deacidify paper, a technique developed by Nitrochemie Wimmis AG of Switzerland. A member of the Rheinmetall Group, the company initially employed the so-called Battelle process for paper deacidification with two processing chambers in Switzerland. But Nitrochemie soon optimized the process, because the original Battelle method had many side effects, including magnesium buildup and spilled stamping and printing ink, which detracted from the results of deacidification. In 2015, the company established the world’s largest facility for paper deacidification at Aschau am Inn, which features three additional processing chambers. Thus far, over 1,800 tons of books and archive materials have been deacidified. Since last year, works from the Marbach archives have also been processed at the Aschau plant. Doing this requires special chemicals based (among other things) on magnesium, which the company produces on site.

Financed through charitable contributions

For DLA, deacidification is familiar territory. As early as the 1990s, various methods available on the market were thoroughly checked and tested until the company finally settled on the nonaqueous Papersave method.


Since 2014, Melanie Kubitza has organized the deacidification of DLA’s endangered literary treasures. Every year, more than 10,000 books and manuscripts by famous authors are deacidified. The project is primarily financed through charitable contributions.

First comes the test

When it comes to conservation, Kubitza takes a very systematic approach: “We evaluate every book and every archived item in order to determine if it is suitable for deacidification. For instance, historical leather-bound volumes or parchment are taken out, because the Papersave process would leave them brittle.” Furthermore, certain writing media and printer’s inks bleed out and leave unwelcome traces. Additional indications regarding the acidity of the basic material can be obtained with the help of a pH pen. Each manuscript or book is subsequently recorded with a printout featuring a barcode. Only then – after being transported to Aschau am Inn – do they undergo deacidification packed in meshed containers. A further advantage: deacidification in accordance with German DIN norms makes it possible to apply an alkaline buffer to the material, which protects the paper from future damage from acidity. Great care is also taken following the de-acidification process. As Kubitza explains: “Each de-acidified book or document is individually inspected for possible damage. This goes to show just how important preselection is, because fewer than 5% of the items display evidence of side effects, which is a very good proportion.”

250 years of literary history

In Marbach, where it all began with the acquisition of items from Friedrich Schiller’s estate, the DLA safeguards a vast collection of historical literary and philosophical documents covering the period from 1750 to the present, making it one of the world’s most important cultural archives. In addition to the papers and personal effects of over 1,400 famous authors, among them Hermann Hesse and Franz Kafka, the collection encompasses the archives of several publishing houses, including Cotta and Siegfried Unseld (Suhrkamp). Manuscripts, pictures, and other objects belonging to DLA are on permanent display at the National Schiller Museum as well as the Museum of Modern Literature, both of which form part of DLA.

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