Conservation of the 1641 Depositions
The conservation project aimed to stabilise the media, and repair and rebind the documents to ensure their preservation into the future. The documents varied in condition due to the effects of the aging of the iron gall ink inscriptions, which in some cases had caused staining and perforation of the paper. The 18th-century bindings were in poor condition, and old paper repairs had also contributed to the unstable state of some of the documents. Access to the documents for digitisation was not possible without causing further damage to the paper and the structure.
The treatment methodology was developed taking account of guidelines on the treatment of iron gall ink corrosion established by the Netherlands Institute for Cultural Heritage. This involved pre-treatment assessment of the stage of deterioration, and the use of a calcium phytate/calcium bicarbonate stabilising procedure.