Libraries in Germany – Conservation

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Paper may be long-lasting, but it is by no means resistant to every threat. The Centre for Book Preservation in Leipzig helps paper in its fight against acid decay and ink corrosion, against mould and insect damage, as well as against disasters of a less everyday nature.

The talk is of a sandwich, of gelatine and of freezer contents, but it is not prowess in the kitchen that is at stake here, but how to save literary treasures. In the Centre for Book Preservation, newspaper pages are filled like sandwiches, paper is smeared with gelatine and books are freeze-dried. The aim of all these measures is to halt the process of decay.

Providing services to libraries, museums and archives

The Centre for Book Preservation was established in 1992 at the German Library –Leipzig German Library to develop mechanized systems by which to treat large quantities of at-risk or damaged books, newspapers and other paper-based documents.

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The Centre for Book Preservation (or ZFB for short) was privatized in 1998. Today, a permanent staff of around 20 – among them restorers, bookbinders and chemists – is dedicated to the care of its paper patients in the Heiterblick business park in Leipzig. The ZFB provides a wide range of book preservation services, extending from the traditional craft of restoration to mass de-acidification using the very latest technologies. The Centre's customers are libraries, museums and archives.

The problem of acid decay

But why does paper require de-acidification or splitting in the first place? This is because paper which was manufactured industrially from the mid 19th century right up to the 1980s contains acid, which causes the paper to deteriorate after around 50 to 100 years.

Acid decay, as this phenomenon is known, is the biggest problem facing paper conservationists, and almost two thirds of all book stocks worldwide are affected. The way the ZFB treats the problem varies depending on the extent to which the decay has already advanced.

Mass de-acidification using the papersave® process

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Providing the paper has not yet become too brittle, it can be treated in a de-acidification system. The books are gently warmed and dried in a vacuum in a steel tube, thereby reducing the water content of the paper from approx. 6 to around 0.5 percent. Next, the books are soaked in an alkaline solution. Though the solution is recovered after this process, one chemical remains in the paper, neutralizing any acids present yet without damaging the covers, seals, inks or dyes.

To provide long-term protection, an alkaline reserve is also introduced at the ZFB; a higher degree of this alkaline reserve is stored in the outer edges of the pages because this is where the books are particularly susceptible to ageing. Before the treated books can be returned to their former place on the shelves, they need to be dried and aired one more time. The ZFB can de-acidify 80 tons of books, newspapers and files each year.

Mechanized paper splitting

If the paper has already deteriorated too far, the staff of the ZFB use a different process: mechanized paper splitting. While mass de-acidification merely halts the process of decay, the paper splitting process developed by the ZFB can permanently restore the sheets of paper.

Paper splitting started to be practised by restorers back in the last century. The brittle sheet is smeared with gelatine and then carefully pulled apart in the middle. To stabilize the paper, a wafer-thin but very strong sheet is glued between the two halves – for decades, this was a job which was done painstakingly by hand.

Now, thanks to the world's first automated splitting machine which was developed at the ZFB, large quantities of paper can be treated every day. During the process, the paper is also permanently de-acidified because the inserted core is attached using an alkaline adhesive.

Help in case of disaster

The fight against acid decay is the bread and butter work of the ZFB, yet the Centre's staff are also familiar with disaster situations. When the River Elbe flooded in the summer of 2002, and following the fire in the Herzogin Anna Amalia Library in Weimar in September 2004, they worked almost day and night.

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After the fire, 30,000 books and documents from the Anna Amalia Library received emergency care at the Leipzig ZFB. The first step was to freeze and freeze-dry them. Following this type of disaster, the most important job initially is to bring to a standstill – as quickly as possible – the reactions set in motion by the fire extinguishing water in the paper. This is the only chance to stop moulds from forming, for example, and to prevent inks and colour from running.

The staff of the ZFB picked up the books in Weimar after the fire, cleaned the soot off them, wrapped them in gauze bandages and froze them. During the drying process, the paper is kept at an atmospheric pressure below 6 mb, that is to say in a vacuum. Under these conditions, the frozen water escapes in gaseous form, without damaging the paper in any way.

Theoretically, the books could remain in the cooling chambers for around ten years. This gains valuable time for customers who have suffered some sort of catastrophe – for example when the financial means are not available to fund restoration immediately. The ZFB in Leipzig, in other words, saves files, magazines and books from certain death – using a process by which instant coffee and food for astronauts are also manufactured.