- Take necessary human safety* precautions
- Stop the flow of water
- If water is dripping, cover collections with plastic sheeting and place buckets under the leak
- If water is on the floor, contain further spread
- If possible, move nearby, but still dry collections to an unaffected space
- Keep the affected space cool (below 65 degrees F if possible)
- Reduce the humidity (below 40% if possible) by circulating air, turning on air conditioning, removing water from the floors, etc.
* Human safety threats include: mold; biological or chemical contaminated water; electric shock; etc. In some cases, personal protective equipment (e.g., waterproof gloves and boots; coveralls; face masks; respirators) may be sufficient, but when in doubt, always put human safety first.
Air drying is practical if there is convenient access to sufficient work space with a controlled environment (below room temperature and 30-50% RH) and the number of wet materials is small enough so that setting up items to dry can be completed within 24-48 hours.
Note: Air drying can be accomplished with everyday supplies and therefore does not necessarily require an outlay of money (it requires labor and time), but even when done correctly does not provide the best results compared with other drying options (Disaster Recovery: Salvaging Books, Conservation Center for Art and Historic Artifacts [PDF: 267 KB / 6 pp.]).
Supplies needed: clean towels; unprinted paper towels; fans, if available.
Set up work space: Keep temperature cool and humidity low. Lay out clean towels on clean, stable, flat work surfaces OR set up clean, rigid, plastic screens (if possible, elevate screens on blocks for increased air circulation). Use fans to increase air circulation, but do not aim fans directly at the drying collections.
Precautions: Wet paper is heavy and very weak and therefore will tear easily. Handle gingerly and support the full surface area at all times whenever possible.
- Lay items flat on clean absorbent towels/unprinted paper; change absorbent towels regularly until item is just damp
- Do not attempt to separate soaking or very wet sheets; leave in 1/4” thick stacks and separate when just damp
- If media is not water soluble, blot excess water off the surface
- When items are just damp, sandwich between new paper towels and lightly weight overall to flatten
- Do not air-dry glossy (coated) paper, parchment; immediately freeze
- For normal sized, hardcover books in good condition without bleeding media: Follow appropriate drying procedures according to how wet the book is ("Procedures for air drying wet books and records," Cornell University Library)
- Using paper towels or other interleaving that is larger than the book and therefore protrudes will accelerate drying
- Check drying books frequently to ensure no mold is growing, especially between the leaves and in the gutter of the book
- Large, heavy, fragile/damaged, or soft covered books: Follow instructions above, but keep flat
- Do not air-dry books with glossy (coated) paper, leather, parchment, rare books; immediately freeze
Photographs and Negatives:
- Prioritize drying prints before films
- Do not allow prints or films to partially dry before setting up to air-dry; if necessary, keep waiting items in clean, cold water
- Separate prints from frames, storage enclosures, or each other and lay out emulsion* side up; avoid touching emulsion
- Remove films from storage enclosures and clip (along edges) to drying lines
- If items are stuck to glass or to each other, freeze
- If items are soiled with wet mud, gently rinse in clean, cold water, before setting up to air-dry or freeze
- Items will curl upon drying; leave flattening to a conservator
*On negatives and color slides, the emulsion side is usually less glossy.
Note: Some photographic materials (e.g., wet collodion, ambrotypes, tintypes) are very sensitive to water damage and may not be recoverable.
- Emergency Salvage Procedures for Wet Items (Minnesota Historical Society). Covers archaeological items, decorative objects made of organic and inorganic materials, magnetic media, grooved records, and textiles.
- Emergency Treatment For Water-Soaked Furniture And Wooden Objects (National Park Service [PDF: 281 KB / 2 pp.])
- Emergency Salvage of Wet Books and Records (Northeast Document Conservation Center). Includes optical discs (e.g., CDs, DVDs) and magnetic tape (e.g., videotape, cassettes).
- Hard drives: Remove from computer shell, place in zip plastic bag or plastic container, and send to a recovery company
1. Freezing buys time when the number of wet items makes it impossible to air dry within 48 hours. Frozen items can be thawed and set up for air drying in more manageable batches.
2. For certain types of materials (see list below), immediate freezing is the only option available to prevent total loss.
What to freeze:
- Immediately freeze glossy (coated) papers and items with thinly applied soluble (bleeding) media to prepare for vacuum freeze drying (Freezing and Drying of Book, Paper and Photographic Materials, Conservation Center for Art and Historic Artifacts [PDF: 130 KB / 4 pp.])
- Freezing also recommended for leather, parchment, and rare books
Freezing in a household freezer is an option, but adjust to the coldest possible setting. Note: household freezers may not reach cold enough temperatures to prevent the formation of large ice crystals in the items, which can cause damage.
A freezer with a "frost-free" setting can, over months, dry out items ("freeze-drying"), which can be preferable to air drying.
Disaster recovery vendors (New York State Archives) can provide the best options when a large number of items are wet or when more advanced, industrial equipment is otherwise needed. Vendors can provide regular freezing followed by air drying, blast freezing (which helps minimize the formation of large ice crystals), freeze drying, and vacuum freeze drying.
Guidelines for packing books for freezing (University of California, San Diego)
Note: Recovering collections from a mold outbreak is time consuming and costly. Furthermore, despite best efforts, results after the collection item is stabilized and cleaned may be still considered unsatisfactory for a variety of reasons. If the mold-affected collection item is considered a replacable item, replacement often requires the least labor, resources, and time.
- Active/growing mold looks fuzzy or slimy; do not disturb active mold; first stop mold growth by controlling the environment
- Dormant mold is dry and powdery; follow appropriate human safety precautions when dealing with dormant mold
Mould Outbreak — An Immediate Response (Canadian Conservation Institute)
Smoke and Soot
- Wear latex or nitrile gloves before handling items covered in smoke or soot; hand oils will drive smoke and soot particles into items and cause more damage
- Blot (do not rub) smoke/soot off with a vulcanized rubber sponge
- Always put human safety first
- Wear personal protective equipment if items must be handled
- Consider whether the contaminated items must be saved or whether disposing and replacing is a better option
- If the item must be saved and can tolerate water exposure, carefully rinse in cold, clean water until contaminant is washed away
The preservation procedures described here have been used by the Library of Congress in the care of its collections and are considered suitable by the Library as described; however, the Library will not be responsible for damage to your collection should damage result from the use of these procedures.