Nationaal programma voor het behoud van het papieren erfgoed

Paper conservation

Metamorfoze's main concern is preservation of the originals themselves. Therefore Metamorfoze works with two methods of conservation. 

The content of the threatened material is transferred to another storage medium by means of digitization (preservation imaging). The material is treated by means of small repairs, acid-free wrappings and climate controlled storage. If necessary, the material is treated against autonomous decay.


In the mid-nineteenth century, the mechanisation of the printing process gave rise to a rapid increase in the demand for paper. This led to a shortage of rags, the original basic component of paper, so rags were replaced by cheap wood pulp. The combination of wood pulp with the chemical processes applied in paper production considerably shortened the life span of paper. It becomes acidic, turns brown and brittle and finally disintegrates altogether. External influences such as air pollution, climate change and careless treatment of the document also have a harsh impact on paper quality.

Ink corrosion

From the Middle Ages to the twentieth century, documents were written in iron gall ink, an acidic ink that eats its way through paper fibre. The chemical processes to which the ink is subject, along with oxidation, cause the paper fibres to break down further and further. The ink becomes badly discoloured, the written letters drop out of the paper and holes appear in the documents.

Copper corrosion

In the past, verdigris was used as a pigment for colouring maps. Over time, the pigment sinks into the paper and stains the reverse of the page. In the areas where verdigris is applied, brown discoloration and spots occur. As in the case of ink corrosion, the paper in these areas finally becomes so weak that holes appear.