Glycerin Chamber
Definition
Sealed humidification chamber held at 60 to 80 percent relative humidity using glycerin-water solutions to restore flexibility to charred or brittle paper before unfolding and imaging.
- Humidity range
- 60 to 80 percent relative humidity
- Solution used
- Glycerin-water solution
- Purpose
- Restore flexibility to charred or brittle paper
- Application stage
- Before unfolding and imaging the document
Common questions
Why can't a charred document simply be unfolded without humidification?+
Charred paper is extremely brittle and fragments or crumbles under mechanical stress, so unfolding it dry risks destroying text and structure; controlled humidification softens the fibres enough to allow careful separation without loss.
How long does a document typically stay in a glycerin chamber?+
Exposure time varies with the degree of charring and paper thickness, examiners monitor the document and remove it once it becomes pliable enough to handle, since over-humidifying risks further damage or mould growth.
What happens to the document after it leaves the glycerin chamber?+
Once flexible, it is carefully unfolded or separated under magnification, photographed or scanned, often with oblique or infrared imaging to enhance faint text, and then stabilised or encapsulated for long-term preservation.
Related terms
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