Paper is a fascinating material. A favourite material used by artists, it can endure for centuries if properly made, handled and preserved. It can also be quickly destroyed by accident or through carelessness.
The process of making paper today is remarkably similar to methods used seven hundred years ago. Of course, modern machinery has increased manufacturing capacity and technology allows us to control quality, cost, longevity and other characteristics. Consistency and variety are our modern advantages but paper is still much the same as it has been all along.
A well-trained and experienced custom picture framer can help you preserve as well as present valuable paper items. However, some picture framers are not qualified in matters of preservation and may unwittingly cause damage or destruction. You must learn enough to judge the skill, knowledge, and integrity of your framer and others who handle your paper treasures. We, at Atelier Daniel, have over 30 years of experience with paper and have followed several courses on paper handling and conservation.
If your valuable paper item is already damaged, perhaps it can be repaired. Bring it to us and we will consult a qualified paper conservator (an educated specialist who knows the chemistry of papers, inks, and other related substances) to see what can be done to restore the work to its original condition .
Most of us handle paper every day, but know relatively little about its care and preservation. Paper has more "enemies" now than at any time in history. This brief overview is intended to improve your awareness of potential hazards and help you prevent their harmful effects.
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.
THE ENEMIES :
HOW TO MINIMIZE THEM :
INHERENT FAULTS
Stray pieces of fibre or metal in the paper.
Marks from hasty drying, curing.
Alum content (sizing) which will eventually destroy the paper from within.
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.
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.
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 colour), mat board, wood frame mouldings.
Store in acid free packaging that provides a barrier against acid migration.
Frame with non-acidic materials. NOTE: Standard mat board 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.
HUMIDITY
High humidity causes expansion of paper's fibres, making it more susceptible to surface abrasion and shredding. Also, the higher moisture content encourages insects, mildew and mould.
Low humidity causes contraction of paper's fibres, making it more brittle and susceptible to tearing.
Frequent or rapid changes in humidity stress the fibres. If the paper is mounted, it can actually tear itself from its mounts, due to radical expansion and contraction.
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).
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 mould and insect growth.
Low temperatures are generally not a problem.
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).
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 fibres, 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.
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 and in 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.
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.
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.
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:
Sulphur - From combustion of fossil fuels such as coal, natural gas, and oil.
Chlorides - "Salt air" - can come from evaporation of perspiration or steam of cooking.
Nitrogen Oxides - From traffic exhausts and deterioration of photographic films.
Keep out of garage, furnace room and other areas where combustion and its by-products exist.
Keep in a properly-closed picture frame.
Keep in tight packaging of acid-free material.
Encapsulate.
Use filtered air
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.
MOLD
Mould (fungus) spores are ever-present in airborne particles. They settle and germinate into tiny plants where conditions are favourable.
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 favourable conditions.
Avoid by keeping temperature and relative humidity under control, and keep air circulating.
Avoid dust and dirty areas.
If mould 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 mould killers.
PHYSICAL DAMAGE
Creases, folds, wrinkles, rips, cockling, marks, punctures, and cuts are usually irreversible.
Prevent. Prevent. Prevent.
Handle as little as possible.
If you must handle paper, use both hands, and use supports over and under the sheet.
Rolling is somewhat harmful, but it is better than attempting to transport flat and unsupported.
Frame it or store it as soon as possible.
Most physical damage is permanent. However, some harm can be repaired and /or cosmetic treatment can help and can prevent further damage. Consult a qualified paper conservator.
Atelier
Daniel – your specialised custom
framing store in Montreal.
