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THE ENEMIES OF PAPER AND HOW TO MINIMIZE THEM James A. Miller, Certified Picture Framer 1698 Hill Road N. Pickerington, Ohio 43147 614-868-5554 / FAX 614-868-0440
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the ENEMIES INHERENT FAULTS
Newsprint, for example, will be in durable condition for no more than a couple of decades, perhaps less. That is its nature by design. It is not intended to endure, and contains inherent faults. Note that even the best papers may have imperfections, but if these will not affect the longevity of the sheet or its suitability for the intended use, they are generally acceptable. ACID Acids are inherent to the manufacturing process of many papers. Lignin, a component of wood (and its pulp) makes acid as it degrades. Alum, a popular sizing, destroys paper in a few years, from within. Many of the books in our libraries, printed this century, will be lost to acid destruction within fifty years. Acid can migrate from its "host" material (wood, wood pulp paper) into paper that was originally acid free, causing the tell-tale acid burn we often see in framed pieces. Some of the worst common offenders are corrugated cardboard, Kraft papers (brown or colored), matboard, wood frame mouldings. HUMIDITY High humidity causes expansion of paper's fibers, making it more susceptible to surface abrasion and shredding. Also, the higher moisture content encourages insects, mildew and mold. Low humidity causes contraction of paper's fibers, making it more brittle and susceptible to tearing. Frequent or rapid changes in humidity stress the fibers. If the paper is mounted, it can actually tear itself from its mounts, due to radical expansion and contraction. See also: Temperature TEMPERATURE High temperatures increase molecular activity and organic reactions, which accelerate aging. Temperature and relative humidity changes are directly related. Warm air can hold more moisture than cool air. In winter, for example, RH levels are much lower than in summer. High temperatures and high humidity often go together, which compounds the effects of each. Above all, this condition of high temperature and high humidity encourages mold and insect growth. Low temperatures are generally not a problem. See also: Humidity LIGHT Sunlight is most harmful because it is most intense and contains the full spectrum of light. Ultraviolet (UV) light is on the high-frequency end of the light spectrum. It is responsible for fading, and is common to sunlight, fluorescent and some other artificial light sources. Infrared (IR) light is on the low-frequency end of the light spectrum. It is responsible for generating heat (increasing molecular activity), accelerated aging, brittleness, weakening of fibers, and discoloration. It is common to sunlight. Most artificial light sources also emit IR, but it is considered relatively low-intensity and slow to cause damage. Note that light damage of any kind is cumulative - depending on duration and intensity, and is irreversible. PESTS Mice, carpet beetles, clothes moths, powder post beetles, furniture beetles, flies, silverfish, cockroaches, book lice all feed on paper's components; mainly starch and cellulose. Damage can be done by the pests themselves, their larvae, eggs, excrement, and carcasses. AIRBORNE POLLUTANTS Chemicals and particles in the air we breathe can destroy paper. They are usually unseen, and difficult to identify until damage shows. Here are some common ones and their sources:
MOLD Mold (fungus) spores are ever-present in airborne particles. They settle and germinate into tiny plants where conditions are favorable. Germination is common where there is poor air circulation, RH over 70%, and temperatures over 70 degrees F. However, once germinated, growth can continue in less favorable conditions. PHYSICAL DAMAGE Creases, folds, wrinkles, rips, cockling, marks, punctures, cuts are usually irreversible. |
How to Minimize Them Choose good quality paper. Paper made of 100% rag is intended for permanence and is recommended for artworks. Good quality alpha-cellulose papers, with chemical buffers against acids, are also suitable. Avoid most copier papers, Kraft papers, newsprint, construction papers, recycled papers, and others of questionable content and longevity. Generally, inherent faults cannot be corrected, although the effects of acid can be slowed by addition of chemical buffers during manufacture, or later by a qualified conservator. Store in acid free packaging that provides a barrier against acid migration. Frame with non-acidic materials. NOTE: Standard matboard available today is called "acid-free" by virtue of calcium carbonate or other chemical buffers. It is still wood pulp paper and will eventually turn acidic when the buffer is exhausted. If acidic materials must be used for framing or storage, provide a barrier of at least two-ply 100% rag or alpha-cellulose paper; four-ply is preferred. The acid content of most papers can be neutralized even after manufacture by addition of chemical buffers (usually applied by soaking) by a qualified conservator. Acid damage is irreversible. Generally, 50% relative humidity is considered ideal, regardless of temperature. Paper is hygroscopic - that is, it absorbs moisture like a sponge. When humidity changes, it tries to maintain its equilibrium moisture content (EMC). The slower the rate of change, the better. Slow down the rate-of-change of humidity by insulating the paper in proper framing or other packaging. Keep in an area of constant humidity, if possible. Keep in a closed container with silica gel, an inert desiccant material that can be conditioned to maintain a certain range of relative humidity (RH). Cold storage is best (with 50% RH); organic reactions are slower, and insects are less likely to invade. Keep temperatures stable; avoid rapid changes, such as might occur during transport in seasonal extremes. "Insulate" with proper framing or packaging, to slow the rate of change (especially during transportation). Store or display in dark or low-light conditions. Avoid sunlight, fluorescent light, and other artificial light of high intensity. Usually, five foot-candles is enough for viewing or reading comfortably. UV damage (fading) can be slowed or nearly stopped by the use of UV-filtering glass or acrylic in framing, window coverings, light fixture lenses. Note that even minimal light levels are harmful over long periods of time. The only way to completely stop light damage is to keep your paper in the dark. See also: Pests Prevention is best, since damage is usually well underway before the pests are discovered. Keep in a clean, dry (50% RH ideal) area with good air circulation, in tight packaging. Inspect often. Avoid dark, damp, warm areas. Also avoid areas near food, food waste, or other pest attractions. Note that most pests prefer the dark, but light is harmful to paper, too. This paradox should be handled according to the situation, to minimize exposure to harmful elements. There is no perfect answer. Minimize exposure to possible pollutants:
Airborne pollutants go where the air goes, generally. Filtering is an obvious advantage, but equipment must be maintained. Also, some pollutants will probably get through. Display or storage in a closed room with filtered, conditioned air is better than exposure to outdoor air. Damage from pollutants can continue after exposure is stopped. Conservators can clean away most of these, halting damage. However, damage done is usually irreversible. Avoid by keeping temperature and relative humidity under control, and keep air circulating. Avoid dust and dirty areas. If mold occurs, it can usually be killed and residue removed by a qualified paper conservator. However, some discoloration may remain. UV light and alcohol are effective mold killers.
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What's in a Frame?/Price vs. Preservation/Design Considerations/MYTHunderstandings/Framing for Exhibition/Enemies of Paper
614.868.5554
FAX 614.868.0440
Hunters Run Center
1698 Hill Road North
Pickerington, OH 43147
15 minutes from downtown Columbus, OH
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