StaffGuide: Preservation

Preservation information and resources


books with damaged spines, lined up on shelf

There are numerous ways collection materials are damaged. Sometimes it's the result of poor handling, other times the result of inherent vice (for example, paper breaks down over time or adhesives used to attach a cover deteriorate into a powdery mess). Often this type of damage can be treated and repaired. Water damage, mold, and pest damage may not be treatable.

Help us treat our collections by bringing damaged items to Preservation using the guidelines below and in the Workflows section. Damage is labeled below with the level of impact on the collections: HIGH, MEDIUM, LOW. These levels correspond with the Workflow charts and need for attention.



If an active water leak is discovered, immediately notify Circulation, Preservation, and the building manager (Deb Cheval for Mullins Library).

If an item is wet/damp when returned, put inside a bin, print a bib record and attach to bin, and immediately deliver to Preservation.

If an item is dry but rippled or warped due to water damage (as in the photo below), deliver to the incoming damage shelf in the Preservation. If mold is present, follow instructions for mold; if you're unsure if there is mold, act as if it is present.

book with rippled pages from water damage



Mold may result from a combination of water damage and high humidity, or water damage only (mold can start growing after 72 hours of items being wet). Mold is either:

  • inactive - dry, powdery, often black or white clusters of spores on a surface
  • active - looks fuzzy, smears, may be slimy, clusters of spores in a variety of colors

If you find an item with INACTIVE mold, put it in a sealed Ziploc bag, print a bib record and attach to bag, and bring to Preservation.

If you find an item with ACTIVE mold:

  • If items are on a shelf, do not remove from shelf, and immediately notify Preservation and Circulation
  • If item comes from book return or patron, put it in a sealed Ziploc bag, print a bib record and attach to bag, and bring to Preservation


Examples of inactive mold:

inactive black mold spores on book page

inactive black and white mold spores on book cover

mold on edges of papers that were in a file folder


Example of active mold:

fuzzy mold in black, olive green, and yellow on edges of books stacked on top of each other


Audiovisual materials are susceptible to mold (visible as white spots on this reel). Whether the mold is active or inactive, put item in a sealed Ziploc bag and bring to Preservation.

white mold spots on film reel



Pests--insects and rodents--can cause permanent damage to paper-based items.

If you find an ACTIVE pest infestation, immediately notify the building manager (Deb Cheval for Mullins Library) and Preservation. Do not move any items from the impacted area.

If you find evidence of pests in items on shelves, do not move items on shelves, and immediately notify Circulation and Preservation.

If you find evidence of pest damage to an item, put item in a sealable Ziploc bag, print a bib record and attach to bag, and bring to Preservation.


Images of pests can help you identify any you might find in the building.

Silverfish eat paper and can leave behind extensive damage:

silverfish damage to inside pages of book; parts of pages have been eaten away and look like a reverse contour map

Smoke/Other Odor


While smoke (either from a fire or tobacco/related products) may not necessarily damage the exterior of a book, it can cause a book to smell. Other odors may be picked up by materials depending where they have been kept.

If you find a book that smells like smoke or has an odor, put item in a sealable Ziploc bag, print a bib record and attach to bag, and bring to Preservation.


These books are interleaved with microchamber paper which contains molecular traps to absorb pollutant and acidic particles; treatment may take longer than a month depending on the damage. The books may be reshelved after treatment.

books interleaved with microchamber paper to absorb the smell of smoke


Foxing in paper shows as spots of reddish-brown discoloration, much like the color of a fox. Commonly found in items from the 18th and 19th centuries, the spots may be a fungus or a result of ferrous oxide (iron) deposits from water that was part of the paper making process. Higher levels of relative humidity can contribute to the development of foxing; keeping paper-based items in 30%-50% relative humidity will slow the growth.

Items with foxing will not damage other books and do not need Preservation review. However, if you are unsure if you are seeing foxing or mold, bring any items to Preservation for review.

rust colored spots of various sizes covering the title pages of open book

Detached or Separated


Book spines may become detached, and the book's textblock (all the pages that make up the book) may become separated from book covers.

If you see an item with book parts detached or separated, do not attempt to repair; bring it to Preservation and place on the incoming damage shelf.

textblock separated from covers

books with damaged and loose spines on a book truck

Brittle Paper


Brittle paper is the result of acid and lignin in the wood pulp used to make paper, and is often present in materials from the late 1800s through the early 1900s. The paper breaks easily, meaning items are extremely fragile. Books with brittle paper are housed in boxes to protect them and prevent damage to edges.

Brittle newspaper is very common due to the acid and lignin in the wood pulp of the paper:

brittle pages, edges are frayed and broken

Bound books with brittle paper exhibit breakage, on the page edges and sometimes along the gutter of the binding:

Tape and Adhesives


Regular tapes (cellophane, masking, duct, etc.) and adhesives (glue, rubber cement, etc.) damage paper and are difficult to remove. They can dry out over time and discolor the areas they once covered. They can also leave sticky residue behind.

If you find an item with tape or adhesive damage, do not attempt removal; bring it to Preservation and place on the incoming damage shelf.


Examples of tape damage due to improper repair attempts:

book page with yellowed cellophane tape      tape on page in book

poor repair to hinge; white tape on marbled endsheets


Red Rot


Leather deteriorates over time, and this breakdown results in the leather leaving behind a reddish powdery substance on whatever it touches. From the SAA Dictionary, red rot is most commonly found on vegetable-tanned leathers from the later 1800s and early 1900s. As a result of the tanning process, the leather is naturally acidic. Prolonged storage in or exposure to high relative humidity, environmental pollution, and high temperature affects the fibrous structure of the leather leading to the hardening and embrittling of leather and eventual disintegration into red powder if left untreated.

Examples of red rot:

old leather book covers with dried covers exhibiting red rot

books on book truck, red rot visible on spines