Basic Instructions For Drying Books

Reprinted with permission from the Northeast Document Conservation Center

Last updated June 2003

Drying Soaked and Dripping Books with Covers Intact

Stand the closed book upright on the top end. Do not fan leaves to make the volume stand up; merely open the covers slightly and let stand while draining. To proide further support during draining, use Styrofoam or similar (non-absorbent) material cut 3/16″ wide and slightly longer than the thickness of the text block (pages without covers). Place a piece under the opening edge of each book to keep it balanced upright and tilted slightly backward. A toothpick placed under each cover about midway from front to back will keep the covers in position while water is draining.

Books should be stood on several sheets of absorbent paper cut the approximate size of each book. Unprinted newsprint stock is cheap and will work well for this purpose. It is important that these sheets be replaced frequently as they absorb water, and the wet sheets should be removed from the working area. The covers of books are usually the last parts to dry out, and the area between the board papers and flyleaves will be the first attacked by mold. Place a sheet of aluminum foil, polyester, or polyethylene film between the covers and the leaves of the book. The inner portion of the book will dry first, and the foil or plastic sheet will prevent the water held in the covers from migrating to the inside of the book. Circulating air using fans and frequently changing the absorbent paper under each book will dry the books to the point at which, with care, they can be opened with little damage.

Proceed with great caution when first attempting to open a book which has been drying. Keep the opening shallow and do not open the covers to more than a 30-degree angle at the first attempt. As soon as the book can be opened safely, begin interleaving with sheets of unprinted newsprint or strong paper towels at intervals of 25 leaves (50 pages), starting from the back fo the book. Keep books in the upright position during this interleaving/drying stage.

Change interleaves frequently. Be careful not to interleave too much, or the spine will become concave and the volume distorted. Interleaving should not exceed 1/3 the total thickness of the volume. If drying conditions are unfavorable because of high humidity, it may be necessary to interleave every 5 leaves, and to change sheets ever 2 or 3 hours to dry the book with reasonable speed. Under these conditions, a distorted book is preferable to a moldy book. As the book becomes drier it can be opened flat on the spine and boards and interleaved more closely.

Some further tips:

  • Used and damp interleaving sheets should not be reused
  • Frequent changes of interleaving material is much more effective than allowing large numbers of sheets to remain in place for extended periods
  • Newsprint should not be left in books after drying is complete. A good grade of paper toweling is more effective than newsprint, but the cost is significantly greater, especially for a large collection.

Drying Partially Dry (Not Soaked and Dripping) Distorted Books on Lines

Books become distorted by water swelling the leaves and by interleaving. In such cases, the spine forms a concave shape when the book is closed. Hanging partially dry volumes across 3 or more lines will help the spine return to its original shape as it dries. Such lines should be monofilament nylon, not more than 1/32″ in diameter not more than 5 – 6′ long, and approximately 1/2″ apart – three lines are enough for a volume of ordinary thickness; up to 1″. Books are hung with the spine parallel to the lines which are in the gutter Be sure the weight is not supported by less than three lines. Thicker volumes will require more lines, but no volume should be hung up if it weighs more than 6 pounds (because) the inner folds of books sections are often thin and certainly fragile when wet. Ranging a heavy book in this condition will cause the folds to fracture. Do not hang books saturated with water water under any circumstances. In addition to the danger of mechanical danger, some spine adhesives will migrate through a suspended wet book and cause staining and/or adhesion of pages.

Drying Wet Books with Soft Covers

The technique of wedging a wet book with pieces of Styrofoam to enable it to stand upright for draining is not applicable for books with paper covers or those with covers missing. Such books may be stood on either head or tail. If they will not stand alone, they may be allowed to support each other, with cardboard spacers placed between them. Experience on the site will suggest the best method.

Drying Books with Wet Edges Only

When only the edges are wet omit the drainage procedure. Interleave from the back of the book, turning pages carefuly. Complete the interleaving by placing clean bloter paper inside the front and back covers. Shut the book and placeit on several sheets of absorbent paper without a weight. (Change interleaving as necessary.) As drying proceeds, the einterleaving sheets bcan be removed from the book to expose dry section. Turn the book over ech time it is interleaved. When the leaves are almost dry, a light weight may be placed on the book.

If the edges are only slightly wet, a book may be stood on tis top and fanned open slightly in the page of a flow of air (e.g. a fan). Alternatively, lightweight books may be hung to dry. To minimize distortion of the edges, volumes should be laid flat under light pressure (e.g. paper-covered bricks) just before drying is complete.

If you can establish an air-conditioned room capable of maintaining a constant relative humidity of 25 to 35% humidity and temperatures between 50 and 60 F, books with only wet edges can be dried successfully in approximately 2 weeks without interleaving. Do not try to dry books printed on coated paper by this method. In nearly every case, the only chance of saving such material is to freeze them while wet and dry by vacuum freeze drying.

Final Stages of Conventional Drying

When books are dry but still cool to the touch they should be closed and laid flat on a table or other horizontal surface, gently formed into the normal shape, with convex spine and concave front edge, and held in place with a light weight. Do not stack drying books on top of each other. In no case should books be returned to shelves until thoroughly dry; otherwise mold may develop, particularly among the inner margins.

Dampness will persist for some time in the inner margins, along the spine, and between boards and flyleaves. This is particularly true of volumes sewn on oversewing machines Check often for mold growth.