Hints on Preservation of Documents

Most paper from the nineteenth and twentieth centuries contains acids that cause deterioration, so you will want to slow down the process by storing your paper documents in buffered folders (i.e., folders with neutral acidity; such paper should be advertised as acid-free and lignin-free). Ordinary manila folders are acidic, and envelopes can cause damage to documents as they are removed and replaced. Folding causes tears at the fold line, so be sure to unfold the documents before placing them in the enclosures. Because staples and paper clips rust, it’s best to remove them unless the paper is so brittle that doing so may irreparably damage it. Never use a staple remover, which will tear the paper; instead, use a pair of tweezers or a thin knife to bend up the edges, after which you can gently pry the staple out. For paper clips, slide a stiff piece of plastic under each side of the clip and then gently slide the clip off the plastic.

Newspaper articles, obituaries, and marriage and birth announcements are among the most common documents that families want to preserve. Unfortunately, newsprint is very acidic and quickly turns so brittle that eventually it crumbles at the slightest touch. The best solution is to photocopy it onto buffered paper that is both acid-and lignin-free. The copies will last far longer than the originals. Printing out a legible image on buffered paper from a scanner or digital camera is another option. (When choosing paper, beware of the word “archival”; many manufacturers use that term to describe paper that in fact doesn’t meet accepted preservation standards. It’s best to purchase photocopying paper from archival suppliers.) If the article is already too fragile for photocopying, carefully place it in a sleeve like those described above for photographs.

Never fold a long or wide newspaper article before storing it; once it becomes brittle, it will simply fall apart at the fold. Since most newspapers print articles in columns, it should be possible for you to carefully cut the article into several pieces—provided it is printed on only one side of the page—and then lay the columns next to one another in a sleeve or use more than one sleeve. If the newsprint is so brittle that even the act of putting it into a sleeve might crumble it, your best bet is to keep it flat in a buffered folder. If a folder is to contain multiple pages, place a sheet of buffered paper between each page to prevent acid migration.

Most people never think to unfold letters or documents before storing them. Over time, the paper becomes brittle, making it impossible to unfold without breaking it along the fold lines. Sometimes you may be able to unfold it but the sheet will not lie flat and may deform other documents stored with it. For documents that can’t be safely unfolded, humidification is the remedy. Humidification is the process by which water vapor enters the fibers of the paper, allowing them to relax. Once that happens, you may be able to open them safely so that they can be flattened for future storage.

Before beginning the actual humidification process, gently and carefully clean the paper as much as possible by wiping off dust and grime, because moisture can cause dirt to become embedded in paper fibers, making it difficult to remove later. Of course, you may not be able to clean the entire document if you can’t unfold it; in that case, just clean the outer areas. A brush with very soft bristles is ideal for this. Next, unfold the document if you can do that without damaging it. Because metal fasteners can rust in humid environments, remove staples and paper clips if you can do so safely. It’s better to separate bundles of paper into separate sheets so that humidification will occur more quickly and efficiently, but if the documents are too brittle you can start humidifying the entire bundle and then separate the pages as they begin to relax. Also, it’s recommended that you start the process early in the day, because it takes several hours and you should never do it overnight.

Get yourself a container made of solid plastic with a tight-fitting lid and no ventilation holes. Storage containers made by Rubbermaid or other manufacturers will serve, and are available in different shapes and sizes to accommodate the type and number of documents to be humidified. Remember that the deeper the container the longer it will take for the air inside it to become saturated, thus extending the humidification process. You’ll also need a light diffuser panel — those plastic grids that cover fluorescent lights in drop-ceilings and that can be found in building supply stores. The panel, which should be at least 3/8 of an inch thick, should be cut to fit flat in the bottom of the container (if you’re cutting it yourself wear protective eye gear, as the plastic is brittle). The grid should be small, about 1/2 inch, to provide even support for the paper.

Take a towel cut slightly smaller than the bottom of the container, soak it with cool or room-temperature water, lightly wring it out, and place it flat in the bottom of the container as the moisture source. Place the diffuser panel on top of the towel, and the documents on top of the panel, making sure the documents touch neither the towel nor the sides of the container. Be certain to leave enough room for a folded or rolled document to relax and open without touching the sides or another document, and make sure a rolled document can’t roll off the panel and touch the towel as it opens. If you have several documents that need attention, you can stack the diffuser panels to create layers by placing something (such as small, clean butter tubs) between the panels at the corners to create layers at least three inches apart (this will allow the air to circulate well).

Place the lid on the container and check every fifteen minutes or so. Taking the lid off allows the humid air to escape, so don’t leave it off for very long. The use of clear containers might allow you to check the progress of the document without having to take the cover off. The length of the process will vary, depending on the document, though you should never humidify paper for more than eight hours. You can speed up the process by gradually unfolding or unrolling the paper as it relaxes, after which you can use weights, such as smooth 2 x 2–inch pieces of glass or Plexiglass, to hold it down (make sure the weights don’t have colors that could transfer to the document in humid conditions, and don’t place them on top of ink or other media). When the document has relaxed completely it will stay unfolded or unrolled on its own and may feel cool and slightly (not thoroughly) damp. A damp document will be fragile, so handle it carefully and avoid touching and smudging ink or other media.

There’s one last step: drying and flattening. Take sheets of medium-weight, 100 percent–cotton blotting paper (available from archival suppliers) and cut them into smaller blotters of uniform size, at least one inch bigger than the largest document to be flattened. Place two blotters on a clean, level surface, lay the document flat on top, add two more blotters, and top it off with a pane of Plexiglass (obtainable from glass supply stores) at least 3/16 of an inch thick, of at least the same size as the blotters and with smooth edges. (Several layers of blotters and documents can be stacked under the Plexiglass if necessary, but include only documents of approximately the same size and position them in the same location on the blotters.) Distribute weights (such as heavy dictionaries or encyclopedias) evenly on top of the Plexiglass to provide moderate pressure — you won’t need too many. Then leave the documents for at least twelve hours and repeat if necessary. Don’t worry if a document isn’t completely flat; your objective is to relax it enough so that it can be used and stored without further damage.

Keep in mind that certain items should be treated only by professional conservators, such as exceptionally important or valuable documents (valid wills or deeds, for example), documents made of parchment or vellum rather than paper, photographs, items that are heavily soiled or moldy, coated or varnished papers, and documents with media that are delicate or can crumble (art works made with charcoal, pastel, and gouache are examples of this). There’s always a small amount of risk when exposing paper to water, but humidification is a common procedure that is relatively safe if you are careful. And, of course, to avoid these problems for future generations, make sure you open any letters or documents you’re planning to hand down to your descendants and store them flat in acid-free folders. Remember, once they’re ruined you can’t get replacements!

Musty Odors
Paper is highly affected by the surrounding environment. It’s happiest living in dust-free rooms that enjoy moderate, steady temperatures and relative humidity, clean air, good air circulation, and little natural or fluorescent light. Unfortunately, most of our letters and other documents have spent their existence in less-than-ideal surroundings and have often suffered as a result. Two common problems are musty odors and folded pages too brittle to open. In most cases it’s possible to solve — or, at least, minimize — these problems with some homemade solutions.

You’ll need two clean containers, one large (with a lid) and one small. Garbage cans are ideal, but make sure they’re new or at least very clean — you don’t want to replace the smell of mold with that of garbage! In the bottom of the larger can, place some type of odor-absorbing material, such as baking soda or clay kitty litter. Put the documents into the smaller can, and place that inside the larger can. Be careful to keep the deodorizing material from touching the book. Then place the lid on the larger can and leave it overnight in a cool place. It may take a number of days before the smell is absorbed, so you will need to check once a day. Also, while you’re at it, check to make sure that no mold is growing; if it is, the surrounding environment is too warm and damp.

Heritage Preservation is a national nonprofit organization dedicated to preserving the cultural heritage of the United States. By identifying risks, developing innovative programs, and providing broad public access to expert advice, Heritage Preservation assists museums, libraries, archives, historic preservation, and other organizations, as well as individuals, in caring for our endangered heritage. 1012 14th St. NW, Suite 1200 Washington, DC 20005 (202) 233-0800

New publication (non-member regular price: $24.95, member regular price: $18.00): A team of top museum professionals, assembled by Heritage Preservation, provide practical advice and easy-to-use guidelines on: how to polish silver and furniture without diminishing their value; how to preserve a wedding dress for future generations; the safest materials and procedures for creating a scrapbook that will last; how to care for a photograph album that is deteriorating; creating safe display conditions for ceramics, dolls, quilts, or other treasured collections; and much more.

Paul Schlotthauer has been an archivist and librarian at the New York Public Library for the Performing Arts, Teachers College at Columbia University, and the Queens Borough Public Library. He is currently the archivist of Pratt Institute and lives in New York City. He will also be providing two short articles for the March issue of the Newsletter: how to relax paper (so that it can be unfolded) and how to remove the musty smell from old books easily and safely.