Freeze-Drying (Vacuum Lyophilisation)
Definition
A drying technique in which water is first frozen and then sublimed under reduced pressure (below 611 Pa), bypassing the liquid phase. Used for sodden bound volumes because it removes moisture without the capillary action and surface tension that cause adhesion, cockling, and dimensional distortion during conventional drying.
Related terms
- Cockling
- The wavy planar distortion of a paper sheet caused by differential shrinkage between areas that dried at different rates, typically visible as...
- Controlled Air Drying
- Drying of a wet document flat on acid-free blotter at controlled temperature (18-20°C) and relative humidity (45-55%), separated from adjacent pages, with...
- HPMC (Hydroxypropyl Methylcellulose)
- A water-reversible cellulose ether polymer used in dilute aqueous solution as an ink fixative; applied by atomiser to wet document surfaces to...
- Ink-Fixative Pretreatment
- Application of a dilute reversible polymer solution (HPMC, Cellugel) to the surface of a still-wet document before drying, forming a gel film...
- Mould Remediation
- The physical removal of established mould colonies from a document surface, typically by soft-bristle brush under HEPA-filtered vacuum; carried out when mould...
- Multispectral Imaging
- Photography or remote sensing in multiple wavelength bands beyond the visible spectrum, including near-infrared and short-wave infrared. Drone-mounted multispectral cameras are used...
- Saponin Treatment
- Application of a dilute aqueous saponin solution (a plant-derived surfactant) to a bloodstained document surface to reduce visible haemoglobin staining without significantly...
- Sequential Examination Protocol
- A formally agreed, documented inter-discipline sequence for examining a document that carries both handwriting or text evidence and biological evidence; the sequence...
- Tideline
- A concentrated deposit of dissolved ink chromophores, sizing agents, and mineral salts left at the advancing edge of a receding water front...
Explained in
- Water-Damaged, Wet and Stained Document RestorationA drying technique in which water is first frozen and then sublimed under reduced pressure (below 611 Pa), bypassing the liquid phase. Used for sodden bound vo...