Conserving, Preserving, and Restoring Your Heritage. Kennis Kim

      A sheet of paper can be printed on both sides and then folded one or more times. The folded form is called a signature or gathering.

      • One sheet, folded once = 2 leaves = 4 pages

      • One sheet, folded twice = 4 leaves = 8 pages

      • One sheet, folded three times = 8 leaves = 16 pages.This is the most common format and it is called an octavo.

      Diagram 3: Folds and leaves in an octavo

      Folded signatures are bound together either by sewing a continuous thread along the inside of the fold that comes out as a chain stitch on the spine or by a thread coming out of the fold and wrapping around a cord or tape placed perpendicular to the spine. Sewing causes a slightly thicker block at the spine.

      Bound pages are called a text block. Once the end sheet or end paper is added the text block becomes a book block. Adhesive is applied to the spine to help with alignment and the block is trimmed to open all the folds in the sheets.

      The spine is shaped with a slight curve away from the text to help reduce the bulge at the spine caused by sewing. The spine is then lined with cloth and, sometimes, additional reinforcements.

      Diagram 4: Curved shape of a book spine

      In early bindings and in some hand bindings today, the boards are laced onto the book block and then covered with leather or fabric. In most bindings today, the cover boards and cloth or leather are put together first then adhered to the book block. This is called case binding.

      In a paperback book, the folded edges of the spine are usually not sewn but are ground away, adhesive is applied, and the soft cover is glued on. The glue used for older paperbacks is prone to drying out, leading to loose pages.

       Preservation Concerns

      Books are sensitive to all the environmental factors already considered: light, temperature,relative humidity, and infestation (mould, insects, or rodents). One important factor in the deterioration of leather bindings is air pollution. The absorption of chemical air pollutants, especially sulphur dioxide from car exhaust, accelerates the breakdown of the natural oils and fats in leather, causing bindings to crack with normal handling. There are many abrasive particles present in the air; these particles land on the books causing deterioration of the exposed edges of the paper and bindings, staining, and abrasion.

      It is easy to damage a bound volume through poor handling. Removing a book from the shelf by pulling at the top of the spine (head cap) results in damage and tearing of the binding. Books with damaged spines or failing bindings need adequate support when being handled to prevent separation of the book block from the binding. Additional handling recommendations can be found in Appendix 4: General Rules for Handling and Moving Artifacts and Works of Art.

      The information in books may need to be shared among several people, but photocopying a book is discouraged. Most photocopiers require that a book be open to lay flat at 180 degrees. This can fracture the spine of the book, crack older or desiccated (dried out) adhesives, and break the stitching of older bindings, causing pages to loosen or fall out. If you have to make photocopies, it is important to make one copy onto a permanent durable paper using an electrostatic copier with edge platens that allow books to be copied at 90 instead of 180 degrees. Additional copies can be made from this high quality master.

       Preventative Conservation of Books

      The first step is always to thoroughly examine your book to check for damage, potential problems, and the overall structural stability of the work. One of the most helpful things that can be done at home is good housekeeping. Thoroughly dust the books and storage area and inspect for mould and insect infestation at least once every 12 months.

      Surface dirt should be removed not only to improve the aesthetics of the book but also to eliminate a hazard. Dirt is abrasive, it may be acidic, and it holds moisture that promotes the growth of mould spores. A very light, dry surface cleaning will reduce the amount of dust, fibres, and other foreign materials that may have collected on the surface of the books.

      Diagram 5: Dust removal

      Wearing white cotton gloves, begin by gently blowing away any loose surface dirt with an air bulb. Then brush lightly with a soft natural bristle brush or a soft, lint free cloth. (Old shaving brushes are great for this. Just make sure they are clean and dry.) Holding the book firmly closed, begin brushing from the spine of the book in a downward motion toward and off the open edge of the book block. Use very light pressure; the pages should not move with your brush strokes.

      Another way to remove accumulated dust is with a vacuum cleaner. Using the brush attachment, place a piece of cheesecloth between the brush attachment and the hose to prevent pieces of lose binding or paper from being sucked into the vacuum. With the same motion as used with a brush, clean the book block moving away from the spine. If small pieces are caught in the cheesecloth they should be saved in a small Melinex envelope for structural conservation in the future.

      After brushing and vacuuming to remove loose dust and debris, additional cleaning with a combination of erasers and eraser powders can reduce any remaining surface dirt and grime (see Appendix 6: Surface Cleaning Books). Once the surface dirt has been reduced, the book can be prepared for storage or display.

       Storage and Display of Books

      Storage and display of books are often one and the same. When choosing shelving for books, you should avoid uncoated wood since it emits acid gases that damage bindings and paper. Wooden shelves should be sealed with paint. Do not use Varathane or other oil-modified polyurethane varnishes or oil paint. These products release corrosive materials as they dry and age. Other products to be avoided are alkyd paints, varnishes, one-compound epoxy esters, anti-corrosive paints, alkyd baking enamels, and most wood stains. If transparency is not an issue, coat wood with acrylic or vinyl acrylic latex after sealing any knots with shellac. Allow shelving to dry for at least one month before storing books. If you desire transparency, you could line the shelves with either Melinex polyester laminate or Plexiglas acrylic sheets that may reduce acid transfer. However, there has been no long-term testing of these methods to determine if they do act as a sufficient barrier.

      Teak shelving has two drawbacks as a support for paper and other acid deteriorated artifacts.

      1. It contains Tectoquinone (ß-methyl-antraquinone), a volatile crystal that gives off tectonic acid.

      2. The same oily feel and residue that make teak a durable and long-lasting wood for outdoor use can migrate and cause staining and increased rapid deterioration of cellulose-based artifacts.