Libraries are as the shrines where all the relics of the ancient saints, full of true virtue, and that without delusion or imposture, are preserved and reposed.
Sir Francis Bacon (1591-1626)
What is conservation and preservation?
In the past, conservation and preservation were associated with large university libraries, special collections and archives and referred to practices reserved for rare materials. Today, preservation and routine conservation are, or should be, concerns of every staff member regardless of the size of the library. Replacing books is a drain on new acquisitions budgets and destruction of a book no longer in print is a loss of valuable information or enjoyable literature.
The broader term preservation refers to actions taken to anticipate, prevent, retard, or stop the deterioration of library materials by providing proper storage environments, policies for handling and use, conservation treatment for damaged or deteriorating items, and selective practices employed to maintain as much as possible or feasible the original physical integrity of the physical item. Preservation includes conservation, but also encompasses techniques of partial preservation of the physical object (e.g. a new binding or mending), as well as procedures for the substitution of the original item by conversion. Conversion includes such things as microfilming, digitization, and photocopying. These procedures will not conserve the original physical item but will preserve the intellectual content of the item.
Each library has a wide range of type of materials in its collection including: books, microfilms, photographs, records, compact disks, maps, newspapers, and periodicals. All of these materials are in various stages of deterioration. Most libraries are not so much concerned with preserving and conserving rare materials as they are by dealing with the wear and tear that collections experience through use. Not every item is worth retaining and weeding or purchasing replacement copies is an important part of maintaining collections.
In addition to simply preserving collections from day-to-day wear and tear most libraries have their own treasures, special items that will require preservation. Some items may be of great commercial value. Rare first editions or early newspapers are examples of items that are not only worth preserving for their intellectual content but are considered valuable by collectors. Other items may not have commercial value but will be very important to a community. Photographs, rural newspapers, oral history tapes, and works by local authors are just some examples. The library will be responsible for the preservation of these materials including: ensuring that they are housed under the best possible conditions; determining what materials may require special treatment or facilities to prevent or retard deterioration, and establishing which items merit restoration.
There are many causes of deterioration of library materials including:
- changes in papermaking and binding practices
- insect pests
- use and abuse by people
Some of these problems have various solutions and the challenge to the library is matching preservation needs with the available personnel and fiscal resources.
Impact of changes in papermaking and binding practices
Written material has been produced for several thousand years. Before the 6th century the most common materials used for recording information in the western world were parchment or vellum. Parchment is made of the skin of calf; vellum from the skin of a sheep. This material was extremely durable and many manuscripts have survived to the present time with only moderate deterioration.
In the 6th century, papermaking was introduced to the west from China through the silk trade. Early papermills in Spain (in 1150) and England (in 1495) made paper more widely available. Before 1850, paper was produced from the long, sturdy fibres of cotton and linen rags. Because cellulose fiber, the main component of paper, acts like a blotter and absorbs water readily, paper production requires the addition of a “size” to keep ink from feathering on the paper. Early papermakers used animal or gelatin sizes. In the 17th century alum was added to help the fibres absorb the size more readily. Paper made prior to 150 was very durable and of excellent quality with additives that had no impact on its long-term life. Books produced before 1850 if kept under proper environmental conditions continue to be in excellent condition.
In the mid-1800s the supply of rags dwindled and by 1866, wood pulp became the primary raw material for paper making. Because wood pulp contains varying degrees of impurities and very short fibers, it deteriorates more rapidly than cotton or rag paper. In addition to changing the content of paper, manufacturers switched from animal or gelatin sizes to rosin. Alum was still added to help the rosin absorb. While alum and rosin produced a cost-effective product, they also produced sulfuric acid. The result has been disastrous. Sulfuric acid eventually deteriorates paper and causes it to become brittle. Books produced after 1866 are literally falling to pieces.
Changes in papermaking were followed with changes in bookbinding. Early bookbinding was done by hand. For hundreds of years, beautiful handmade books were produced using various kinds of leather. In the 19th century, bookbinding became an automated process and books were mass-produced. This made them more accessible and affordable for most people, however the result was an inferior product. Inexpensive cloth bindings replaced leather and adhesives were used for page attachment instead of sewing.
These papermaking and binding changes will have a long-term impact on the ability of libraries to preserve information. Over six million volumes in the Library of Congress in the United States are presently so brittle from acidity that their survival is unlikely. At least one third of the material in North American research libraries is brittle. Every year, the National Library of Canada receives hundreds of thousands of items for its collections which are acidic. In fact, it is estimated that 97 percent of the library’s collections are acidic.
Acidic conditions are extremely harmful to cellulose, the primary component of paper. Acid accelerates the breakdown of the cellulose fiber causing it to turn yellow and become brittle.
Paper can develop an acidic nature because of:
- alum rosin size used in papermaking
- atmospheric conditions (e.g. sulfuric acid)
- storage next to other acidic materials (e.g. cardboard, wood)
Solutions to the acid destruction of books include:
|Enclosure||Type of material||Description|
|Phase boxes||Three dimensional materials|
* Worn and damaged materials
* Sets of pamphlets or loose issues of journals
* Music scores and parts used separately but should be housed together
* Books with accompanying maps or charts
* Diskettes, cassettes, and a variety of other materials which are difficult to protect and shelve.
|Two custom-cut strips of alkaline buffered board crossed and adhered to form a two-ply rear board and four Velcro flaps.|
Closures can be buttons and string, Velcrodots, or magnetic strips. They protect materials from light, dust, and mechanical damage as well as radial fluctuations in temperature and humidity.
|Double tray boxes||Two and three-dimensional materials and works of art (e.g. prints, watercolours, plates, photographic prints)|
* More dimensionally stable
* Seal contents more completely
* Easier to open and close.
Disadvantage over phase boxes:
* More difficult to construct
* More expensive than phase boxes
|Two cloth-covered, paper-lined trays, one slightly larger than the other. When closed, one tray fits tightly inside the other. They protect materials from light, dust and mechanical damage as well as radiation fluctuations in temperature and humidity.|
|Acid-free folders||Two dimensional materials. Folders take up more space than encapsulated items.||Made from acid-free and lignin-free board. The board must be strong and stiff enough to protect the item from abrasion and accidental creasing or folding (e.g. light weight Bristol board, two-ply mat board). Folders are joined only on one side. This allows easy access but mean an item can be damaged moving around inside the folder.|
|Encapsulation||Two dimensional materials.|
* Documents, maps, posters, prints.
* Items with printing on both sides.
* Large items that would be awkward to laminate.
* Damaged, brittle, or in need of protection from frequent use.
|Item is sandwiched between two sheets of polyester film. Edges are sealed using double-sided tape, a heat, or an ultrasonic welder.|
|Lamination||Two dimensional materials|
* Documents, maps, posters, prints
* Items with printing on both sides
* Damaged, brittle, or in need of protection from frequent use.
Unlike encapsulation, lamination is irreversible.
|Clear adhesive film is fused to both sides of an item by means of pressure and heat.|
Deacidification is a process that neutralizes acidic components in paper and deposits alkaline compounds into it, providing an alkaline buffer to counteract acidic build-up in the future. Although this process increases the chemical stability of paper, it does not restore strength or flexibility to brittle items.
There are three basic types of deacidification processes:
* Aqueous – involves immersion of paper, sheet by sheet or in batches, in an aqueous solution, or brushing the sheet with an alkaline compound dissolved in water. This process can only be used with items that can withstand contact with water and thus should not be used on watercolours or pencil, charcoal, or ink drawings. The process is very expensive but very effective.
* Non-aqueous – involves brushing or spraying paper with an alkaline compound dissolved in an organic solvent other than water. The process can be used on items that cannot come into contact with water and is a faster process.
* Gaseous or vapour – involves an alkaline compound in the gas phase being forced into the paper. Large quantities of paper can be handled relatively inexpensively in a vacuum chamber.
While deacidification imparts chemical stability to paper, it does not make brittle paper strong again. Commercially available paper strengthening processes are often used in conjunction with, or subsequent to mass deacidification processes.
Because acidic paper is so widespread, only a small percentage of brittle books and papers can be conserved in their original format. Microfilming and photocopying are practical alternatives for retaining the intellectual content of deteriorating books.
* Microfilming – reproduces the image of the original copy exactly. Many libraries replace serial titles (e.g. newspapers and periodicals) with a microfilm edition. Copies can be made from a master copy that should be preserved in a separate location. Microforms are durable, have a long life span, save space, and are relatively inexpensive. They will decay if not stored properly. A number of vendors provide microfilming services.
* Photocopying – is an alternative to microfilming. Readers prefer paper copies to microforms. However, photocopying does not capture detail as well as microfilming. As well, a master copy is not produced from which successive copies can be made. Photocopying must be done on a good machine in excellent working order and on paper that meets the American National Standards Institute Standard for Permanence of Paper for Printed Library Materials (i.e. the paper should be alkaline permanent).
Digitization involves scanning images and storing them in computer databases or on CD-ROMs where they can be easily indexed and retrieved. However, both magnetic tape and CD-ROMs are not permanent materials. Magnetic tapes and discs are made with organic resins that breakdown in approximately ten to fifteen years. CD-ROMs have problems with dust and with plastic coatings bending and deteriorating. Finally, digital mediums are in flux and standards are difficult to apply in fast evolving technologies.
Alkaline paper is made in a neutral or slightly alkaline system that contains calcium carbonate as a filler. The calcium carbonate acts as a buffer, neutralizing any acid that may develop over time. Alkaline “permanent” paper is paper stock that meets the American National Standards Institute (ANSI) Standard. Meeting this standard allows the publisher to use the internationally recognized permanent paper infinity symbol on the flyleaf of the publication. The ANSI states that:
* The minimum pH should be between 7.0 and 7.5
* The quantity of lignin in the paper should be no more than 1% by weight.
* The minimum alkaline reserve should be equivalent to 2% calcium carbonate.
Alkaline “permanent” paper has a number of advantages:
* Paper should have the ability to last several hundred years without significant deterioration under normal library use and storage conditions. Acidic paper has a lifespan of 50-75 years.
* The manufacturing process used for alkaline paper is less polluting than that for acidic paper production. It uses less water to flush out the wood pulp, resulting in less effluent.
* Alkaline paper is slightly less expensive to produce because it requires less fiber per page due to the presence of calcium carbonate as a buffering agent.
* Alkaline permanent paper is recyclable.
All of the fine paper manufacturers in Canada have built new plants or converted old plants In order to produce alkaline paper for all portions of their product lines. Libraries making new acquisitions that they would like to last for a long time, should try to purchase books that have been printed on alkaline permanent paper.
Metal shelves are preferable to wooden shelves. The acidity of wood can hasten book deterioration. As well, varnishes, stains, and paints used on wood can damage bindings. If wood shelves are properly treated they may be acceptable. They must be sealed with an inert sealer and the library materials should be insulated by lining the shelves with a non harmful material (e.g. buffered paperboard). Metal shelves can also be a problem if they are painted with paints that give off fumes indefinitely.
Other causes of book deterioration
The most important step that can be taken to lengthen the life of library materials is to provide a proper physical environment for their storage. All materials need a stable environment and to be protected from insect pests, rodents, fungus, and people.
Paper is an organic substance and the environment has a big impact on the life of paper. Fluctuations in environmental conditions activate properties of acid in the paper’s fibers.
Environmental factors that can affect books include:
- Air quality – air pollution poses a threat to library materials. Sulfur dioxide, nitrogen oxide, and ozone are very harmful. They can cause cellulose to deteriorate by combining with moisture in the air and in the books themselves. The most effective way of providing satisfactory air quality is to have a climate-controlled environment where air intake is regulated and pollutants are filtered out. Since this is not financially possible for many institutions, another option is to have a climate-controlled storage area.
- Light - although all wavelengths of light are damaging to library materials, by far the most harmful light is ultraviolet light. Ultraviolet light degrades cellulose and fades pigments and dyes. Libraries usually have light from the following sources:
o incandescent bulbs
o fluorescent bulbs
o direct sunlight
These light sources have been listed from the least to the most damaging. To combat the damage from light, libraries can:
o turn off lights when not in use
o install ultraviolet sleeves on fluorescent light bulbs
o install blinds or UV filters over windows and skylights
o place valuable materials in a folder or mat and store in a box so that light cannot harm the item.
- Temperature – heat makes printed and other materials brittle. Also, when books are stored in cold places, condensation will form when they are moved to warmer temperatures. The speed of chemical reactions doubles with every increase of temperature of 10 degrees. At 80 degrees Fahrenheit (28 degrees Celsius) books will deteriorate twice as fast as those stored at 70°F (22°C). Most people find 70°F (22°C) to be too cool for prolonged sedentary activity. There has to be a compromise between the conditions for housing the material and conditions for people to sit and work with materials. Library temperatures should be kept at 68°F (20°C) and should not fluctuate more than 3 degrees in either direction.
Solutions to temperature control include:
o keeping books away from radiators
o installing air conditioning
o use of ultraviolet filters to stabilize temperatures and prevent great fluctuations
- Humidity – too much causes books to swell and foster the growth of mould and fungi. A relative humidity of 50 percent (plus or minus 5 percent is optimum for paper). It is a good idea to keep relative humidity below 70 percent and above 40 percent. Mould grows at 80°F (28°C) and 70 percent relative humidity in stagnant air. So air also needs to be kept moving. Fluctuations are especially harmful since shrinking and swelling put stress on the fibers in paper and hasten deterioration.
Solutions to humidity control include:
o installing air conditions
o use of dehumidifiers and fans in summer
o use of humidifiers in winter
- Dust – particles are abrasive and contribute to moisture retention. Solutions to dust management include:
o proper ventilation and air filters
o simple housekeeping routines including:
§ vacuuming books at regular intervals with a cheesecloth filter and a soft brush
§ dusting shelves periodically
§ cleaning floors and furniture regularly
2. Insect pests
There are numerous insects that find book collections a delicious source of nutrition. Food and drink brought in by patrons can also attract insects.
The biggest problems for libraries are:
Insects can be very damaging. A regular program of building maintenance and good housekeeping will keep infestations down. Eliminate food and drink from the library. A professional exterminator will have the expertise to eliminate many insect pests.
Rodents attack paper and food residues. They are very much a seasonal problem In Canada. As winter approaches, rodents seek shelter from the cold and crawl into warm buildings. Solutions to rodent problems include:
- Plugging holes in foundation walls especially around water, sewer, and gas mains
- Eliminating accumulations of waste and debris and food particles
- Using non-chemical means of control (e.g. sticky traps)
- Hiring a professional exterminator.
Spores of various fungi are found everywhere. However they require the proper conditions (moisture and high temperature) to proliferate. A purple-brown stain on paper is often evidence of serious mould growth. Mould weakens paper and eventually destroys it. High concentrations of fungi are also a health hazard and can cause serious allergic reactions and illness.
Solutions to fungi include:
- Good air filtering systems that will help control spore levels
- Maintenance of proper temperature and humidity
- Good housekeeping and sanitary practices
- Isolation of infected items
- Cleansing and sterilization of infected areas
Use and abuse of library materials by people can often cause the most damage. Library patrons are careless about the way in which they handle materials and may:
- Crush the spines of books under photocopy machines
- Crease the corner of a page to mark their place
- Use paper clips or post-it notes for bookmarks
- Underline parts of a book with pen or highlighter
- Squash books onto shelves
- Bring food and drink into the library
- Eat food while handling materials
Libraries need to try to develop a few rules for patrons and enforce them as much as possible through education, signage, and fines. Library staff can also have a big impact on the preservation of library materials. Proper handling of materials in the various areas of the library ensures that collections do not suffer needless damage.
Books spend most of their lives on shelves, so shelf conditions have a great impact on life expectancy.
Library disasters – prevention and preparedness
The slow deterioration of materials can become rapid deterioration when disaster strikes the library. Libraries have been struck by fires, earthquakes, cyclones, dust storms, and civil unrest. However, the most common risk to collection from all types of disaster is water damage. Water may enter the library from floods, broken water pipes, sprinkler systems, leaky roofs, air conditioning equipment, and sewer drains. Water damage can be devastating to a collection.
Libraries need to be prepared for the worst. A disaster plan is a document which describes the procedures devised to prevent and prepare for disasters, and those proposed to respond to and recover from disasters when they occur. The responsibility for performing these tasks is allocated to various staff members who comprise “the disaster team”.
Every disaster has three phases: before, during, and after. A variety of plans help with each of these phases. The ‘before phase’ corresponds to everyday routine operations and includes two types of plans: preventive and preparedness.
1. Preventive plans recommend actions that will prevent most disasters. Repair of leaking roofs and the improvement and upgrading of security are some examples.
2. Preparedness plans are designed to ensure that identified disasters can be managed. They recommend such actions as the identification of important items in the collection, the purchase of plastic sheeting, the provision of freezing facilities and the training of staff to enable them to respond to a variety of disasters.
In the ‘during phase’ a response to the disaster must be made. The effectiveness of this response is governed by the preparedness plan. In the “after phase” recovery plans are implemented. Because every disaster is unique, a detailed recovery plan cannot be made. However, since so many library disasters involve water, be familiar with salvage methods for wet library and archival materials.
A phased approach can be applied to disaster preparedness (as it can to preservation activities in general). Thus, it is acceptable, as a first phase, to begin with a few sections (even in outline form), particularly if the institution focuses on those issues that are of greatest concern. In a subsequent phase, the planners can add more detail and other sections as they become better educated, have time to pursue the plan, and are able to develop consensus on how the institution should organize its preparedness activities.
Cunha, George Daniel Martin and Cunha, Dorothy Grant. Conservation of library materials : manual and bibliography on the care, repair, and restoration of library materials.
Metuchen, N. J. : Scarecrow Press, 1971.
Fortson, Judith. Disaster planning and recovery : a how-to-do-it manual for librarians and archivists. New York : Neal-Schumann Publishers Inc., 1992.
George, Susan C. Emergency planning and management in college libraries. Chicago : Association of College and Research Libraries, 1994.
Lowry, Marcia Duncan. Preservation and conservation in the small library. Chicago : American Library Association, 1989.
Merrill-Oldham, Jan and Smith, Merrily. Library preservation program : models, priorities, possibilities. Chicago : American Library Association, 1985.
Morrow, Carolyn Clark. Dyal, Caroe. Conservation treatment procedures : manual of step-by-step procedures for the maintenance and repair of library materials. Littleton, Colo. : Libraries Unlimited, Inc., 1986.
Swartzburg, Susan Garretson. Conservation in the library: handbook of use and care of traditional and nontraditional materials. Westport, Conn. : Greenwood Press, 1983
Waters, Peter. Procedures for salvage of water-damaged library materials. Washington : Library of Congress, 1975.
WWW site on conservation and preservation
Preservation Department. Stanford University. CoOL : Conservation Online.
A full text library of conservation information, covering a wide spectrum of topics of interest to those involved with the conservation of library, archives and museum materials.