Technique of manual drying
Technique of manual drying
This method is rather laborious, but very effective. Its main advantages are:
- Large formats can be dried
- Before drying, the sorting and shredding is carried out
- After they have been dried, you should clean archival documents that are ready to be stored in the archive – this eliminates the step of conservation
The method of vacuum packing - the treatment step by step
In the case of an acute flood the documentary material should be cleaned from the impurities using clear water and frozen immediately, it should be done no later than 8 hours after flood. The frozen material can be thawed and dried any time, even after several years.
Then the frozen packets are taken out from the freezers one day before the start of the drying procedure, left to defrost slowly at room temperature. After defrosting the curator sorts the defrosted documents (the type of document, its size, its damage ...). This is the moment to choose the best drying procedure (after consultation with a specialist).
If your documentary material has not been too wet yet or you are able to dry the documentary material immediately after flood, no freezing is needed!
Then the smaller material in form of „sandwich“(interleaved with absorbent layers – in order: blotting paper (e.g. newspapers), blank sheet of paper, non-woven textile, documentary material, non-woven textile, blank sheet of paper, newspapers, blank sheet of paper, non-woven textile, documentary material, non-woven textile, blank sheet of paper, newspaper etc.) is placed into a plastic bag (polyethylene) and then it is press-dried in vacuum. After a week, the water is equalized between dried documents and primarily dry layers (newspapers). The packet is then undone and the work process is repeated (with new dry absorbent layers) until the documents are dry (3 – 4 times).
(Notes: In the case of glossy paper the absorbent layer must be inserted behind and in front of each page; The spine of book can be little bit damaged during vacuum-pressing.)
The cleaned photographs are also dried by “sandwich” method. After thawing out the photographs are digitalised immediately. Then (the gelatine layer of photo mustn’t be too wet!) the documents are interleaved with absorbent layers (in order: filtration paper, non-woven textile, photo, non-woven textile, filtration paper, non-woven textile, photo, non-woven textile, filtration paper etc.), are covered by wood board and have been weighted under the open air for 24 hours. Next day, the photos are taken out.
Plans, large documents, tracing-papers, books, common paper up to the A3 format and art papers are dried by “sandwich” method (interleaved with larger absorbent layer in order: filtration paper, non-woven textile, documentary material, non-woven textile, filtration paper, non-woven textile, documentary material, non-woven textile, filtration paper etc.) under the wood board and weight in the open air for 24 hours. Next day, the documents are interleaved again with new dry layers. This workflow is two times repeated. The last procedure is free drying in the open air.
When the material is dry, it is disinfected in an ethylene oxide chamber. Some items must be restored before they are put back in the archive. The above-mentioned process is carried out manually, as decided by specialists, so the material suffers less harm. Given the fact that the archive was flooded by water potentially containing pathogenic microorganisms, strict hygienic rules must be keeping during the entire drying process.
The treatment step by step on the photographs: