Aktuelle Messwerte 02.09.2010

pH-Wert: 8,53
alkalische Reserve: 1,8% CaCo3/kg
Verfestigung: 30%
Single-sheet deacidification
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BCP – the only mechanical single-sheet process which not only deacidifies the paper, but also simultaneously consolidates the paper and sustainably safeguards it from deterioration.

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Bückeburg (BCP) process


  • Fixation of writing materials with Rewin® and Mesitol®
  • Deacidification with magnesium hydroxide carbonate
  • Consolidation of paper with methyl cellulose

 

Zeitungsbestände dauerhaft sichern

Ninety percent of library and archive holdings are threatened with paper deterioration. Nearly all documents, books and newspapers from the last 170 years are affected. When industrial paper production began in the middle of the nineteenth century, demand for raw materials grew. Instead of cloth, wood pulp was used as the basic ingredient, together with a resin sizing which, however, leaves acid-forming substances behind in the paper. Over time, the acid breaks down the cellulose fibres of the paper, causing it to become brittle and fragile. The result is rapid ageing of the paper and eventually decay, which is made worse by mechanical stress and unfavourable storage conditions.

The Bückeburg conservation process

Using the Bückeburg process can successfully bring paper degradation to a stop. It is the only mechanical single-sheet process which not only deacidifies the paper, but also simultaneously stabilises and sustainably safeguards it from deterioration. In the treatment process a mixture of magnesium hydrogen carbonate, methyl cellulose and a fixative in an aqueous solution works its way deep into the paper. The result: Any acids present are neutralised and the alkaline reserve extends the treatment’s long-term effectiveness. At the same time the paper becomes more flexible and is sustainably strengthened by the sizing.

11 million sheets a year

Each year, GSK conserves around 11 million sheets using a total of three large-scale units at sites in Brauweiler and Berlin. The agent solution used in BCP to enable complete treatment in a single operation is constantly being further developed and improved. Regular measurements and laboratory evaluations document the success of the process. This work demands a high degree of care and discretion. Prior to conservation documents are first separated into single sheets which involves removal of bindings and metal parts and, if necessary, cleaning. Then they are foliated, meaning they are marked with a consecutive alphanumeric code so that they can be later sorted correctly and returned to the archive. Accompanying documentation of all the individual work steps guarantees safety and quality.

 

The single-sheet deacidification workflow

 

  • Determining treatment criteria
    A questionnaire is used to establish the criteria for treating the archival materials, and all steps that need to be carried out are determined in accordance with the customer’s wishes. Gentle treatment is guaranteed in all cases.

  • Preparation
    Documents are cleaned and separated, during which bindings, metal parts and adhesions are removed and, if necessary, small tears repaired.

  • Mechanical foliation
    Foliation is carried out by means of a non-contact inkjet printer. The sheets receive an optically uniform consecutive code using an archive-secure age-resistant ink, and sorted according to conservation type.

  • Conservation

  • Mechanical conservation
    Nearly all sheets can be conserved by machine using the BCP process. In the process they pass through a conservation tank and are subsequently dried.

    Manual conservation
    Highly sensitive or severely damaged sheets are conserved manually.

  • Manual restoration
    Minor restoration work such as closing up tears and repair of damaged spots is carried out on severely damaged sheets. Severely damaged single sheets can be stabilised with special padded foil (e.g., Archibond) or Japanese paper.

  • Flattening/packing
    Papers which have been conserved manually or mechanically are collated again sorted in the right order. The extra volume caused by the aqueous solution is reduced by flattening. After this all documents are checked again and packed.

    Accompanying documentation of all the individual work steps guarantees safety and quality.