Freeze Drying Documents
Freeze drying is a process which can be used to preserve and recover valuable documents damaged by water. Freeze drying removes water from documents after they have been frozen, allowing them to maintain their biological structure and preventing further deterioration.
Document Freeze Drying Process
Firstly, the documents are frozen solid in order to maintain their structural form. Next, they are placed in the freeze drying chamber and a high-pressure vacuum is applied to remove any air. When the correct pressure and temperature are achieved, the moisture is converted to vapour. This collects on a condensing surface outside the chamber (typically colder than 40ºC/-40ºF), and turns it back to ice. Finally, a gradual temperature rise completes the process by driving off more vapours and eliminating bound water from the documents.
Freeze drying can typically restore the following documents:
- Books and manuscripts: coated papers, leather, maps, parchment, pulp paper, vellum, drafting linens, text books, reference books, manuals
- Business records and documents: legal files, patient and medical records, x-rays, engineering and architectural plans and drawings, catalogues, reference materials, certificates, contracts, passports, transcripts
- Historical and collectible items: archival documents, rare documents, maps, stamp collections, money collections
- Keepsakes: photographs, leather and hide items, newspaper articles, recipe books, cards, scrapbooks
- Textiles: embroidery and needlework, silks, tapestries
- Artwork: acrylic paintings, linen drawings, water colours
Freeze drying offers a practical and effective solution for water restoration, but the restoration quality depends on the material being freeze dried. Documents made of a variety of materials with different absorption properties may become deformed as expansion occurs at a non-uniform rate. Water can also cause mould to grow or make inks bleed, in which case, freeze drying may not be an effective method for document restoration.
Cuddon Document Freeze Drying Videos
See document freeze drying in action using Cuddon Document Freeze Dryers:
- NZ National Library Video: Freeze drying to restore documents
- Steamatic Australia Video: Cuddon Document Freeze Dryer
Cuddon produces document freeze drying machines for sale worldwide.
View other freeze drying applications.
Freeze drying documents for water damage recovery and restoration.