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The following content was provided by the American Institute for Conservation. Objects of beauty and usefulness surround us in our daily
lives. The clothes we wear, the tools we use, and the furnishings and
adornments in our homes are objects of cultural significance. We value
older objects because they form a tangible link to the past. Artifacts
made by people of other cultures provide insights into the lives of their
creators and stimulate connections with our own experiences Over time, all objects change or deteriorate as a result
of environmental conditions, use, accidents, and natural forces of decay.
How an object is handled, displayed, and stored can mean the difference
between preserving it for many years or for only a short time. You can
take an active role in preserving special objects for your own enjoyment
and for future generations to appreciate. This pamphlet gives a brief introduction to the basic principles
of object preservation. Whether your treasured objects are family photographs,
prints by contemporary artists, or Chinese porcelain, these guidelines
will help you begin to learn how to care for them. The Nature Of Things The objects in your collection may be damaged either by
external forces such as mishandling, an unstable environment, or by the
intrinsic nature of the materials used to make them. Some materials are
much more fragile than others and may have special requirements for care.
By becoming familiar with the materials used to create your artifacts
and the hazards that may affect them, you will be better able to care
for them. There are two basic types of materials: inorganic and organic.
Inorganic materials-nonliving substances such as stone, glass, ceramics,
and metals-are generally considered to be very durable and stable but
not immune from damage. Organic materials include those made from animal
products, such as leather, fur, horn, feathers, ivory, or wool, and those
made from plant products, including wood, paper, and fibers. These materials
are more susceptible to environmental damage than their inorganic counterparts.
Colorants and coatings can also be organic materials. Synthetic materials,
such as plastics, are also typically organic. Plastics have been produced
for more than 100 years and are increasingly popular with collectors.
Some synthetic materials tend to be unstable and deteriorate quickly. Inorganic materials may be easily broken, scratched, cracked,
and worn by exposure to harsh weather. You may notice building facades
or garden sculpture worn away by acid rain or stained by the growth of
moss or lichens. Glass may appear cloudy or drizzled (covered by a network
of fine cracks), or it may occasionally even have moisture droplets on
its surface, appearing to "weep." White crystals of salts may
grow on porous ceramics and stone, disrupting their surfaces. Metals may
corrode in contact with acidic materials and excessive moisture. Corrosion
appears as rust on iron, as the uneven green patina on outdoor bronze
sculptures, or as the condition called "bronze disease." You
may also see green corrosion on brass or silver objects, tarnish on silver,
fingerprints, or marks from packing materials etched into metal surfaces. High light levels, drastic humidity fluctuations, and pests
can be especially damaging to organic materials. Excessive light may cause
fading in textiles or in watercolors painted on paper. Pulp paper products
such as mats and cardboard storage boxes may yellow, and their color may
"migrate" into the matted work of art on paper or the stored
textile. Excessive humidity may cause molds and fungi to grow on certain
organic materials. You may see mildew on textiles or baskets stored in
a damp basement or spotting ("foxing") on works of art on paper
hung on a damp exterior wall. On furniture, veneer and joints may loosen
or cracks may develop as adhesives fail or wood expands and contracts.
In a painting hung over a fireplace or next to a heating duct, you may
see surface darkening, color changes, or cracking, buckling, or flaking.
Leather bindings may turn to dust, and the pages of books may become brittle
and yellow. You may see "flyspecs" or holes chewed in objects
made from paper, textiles, or plant fibers. Photographic images such as daguerreotypes may tarnish;
the paper other photographic images are printed on may yellow or imbrittle
due to acidic vapors in the environment. The Environment and Your Collection The major environmental factors that affect the long-term
preservation of objects are light, relative humidity, temperature, air
pollution, pests, and human error. Radiant energy, the most
familiar type of which is visible light, can initiate or accelerate damage
by chemical reaction, especially in organic materials. The three types
of radiant energy most likely to effect objects are: ultraviolet light,
infrared radiation (heat), and visible light. Ultraviolet light is the
most harmful, causing irreversible damage by initiating chemical reactions
on a molecular level. Both fluorescent lamps and daylight may contain
high levels of ultraviolet light. Daylight also contains infrared radiation,
or heat, which can initiate and accelerate damaging chemical reactions.
Visible light includes all the wavelengths of radiant energy that let
us see color. Relative humidity refers
to the amount of moisture in air. It is stated as a percentage, with 100%
being air fully saturated with water vapor. Organic materials absorb or
give off moisture in a continuous attempt to achieve equilibrium with
the atmosphere. These materials tend to be more stable in a moderate relative
humidity (45%-55%), a condition rarely present in normal exterior or interior
environments. Inorganic materials usually are not affected by relative
humidity levels unless they contain salts or are otherwise unstable. Metals,
however, are best preserved at low relative humidity. Serious damage can
occur when materials are subjected to dramatic, sudden changes in relative
humidity over short periods. Prolonged exposure of organic materials to
relative humidity above 60% - 65% will encourage the growth of molds and
fungi. Temperature is significant
because it affects relative humidity. When moist air is heated, the relative
humidity decreases; when it is cooled, the relative humidity increases.
Temperature is also important because deterioration progresses much more
quickly at higher temperatures than at lower ones. Exposure to heat can
drastically accelerate the aging of organic materials and of many modern
synthetics. Air pollution can be generated
inside buildings as well as outside. Its components include acidic gases,
particulate material, and ozone. Many of the chemicals known to cause
human health problems can also harm objects. Indoor sources of air pollution
include smoke, dust, paints, stains, cleaning agents, and new synthetic
materials such as insulation or carpeting. Both inorganic and organic
materials can be damaged by exposure to pollutants. The effects of indoor
pollutants, such as acidic gases from wood products or coatings, may be
intensified when they are allowed to build up inside cabinets or other
closed environments over long periods. Pests found in the home
vary widely in nature and size, from insects to rodents. Wood, textiles,
basketry, paper, photographs, books, leather, feathers, and especially
organic substances with food residues are very attractive to insect populations.
High relative humidity may encourage the propagation of insects. Low temperature
may make them dormant but probably will not kill them. Human error also affects
the long-term preservation of special objects. Mishandling may lead to
irretrievable loss. Breakage is the most obvious form of damage, but you
may also see fingerprints etched into highly polished metal surfaces,
smudged pigments, torn canvases, pulled or torn textile fibers, and accidents
that could have been prevented with forethought. Steps for Preservation Here are some general guidelines to follow to help preserve
your collection: 1. Minimize the effects of light.
2. Provide stable, moderate relative
humidity and temperature. 3. Minimize the effects of air
pollution. 4. Minimize pest activity.
5. Know how to handle your objects.
Lift sculpture and other three-dimensional objects by the
base or body, never by handles or protruding elements such as extended
limbs. Lift furniture by structurally sound elements such as the seat
frame or base, never by appendages such as arms or legs. Move framed works
of art in a vertical position by handling secure areas of the frame, supporting
the bottom and side. Support paper or textile objects from underneath
on a sheet of acid-free white mat board or white blotter paper. Do not touch the front or back surfaces of oil paintings;
touching can cause cracks and other damage. Never apply cleaning solutions,
sprays, alcohol, or insecticides near any work of art. Use a soft natural-bristle
brush to clean objects and paintings when the surfaces are in good condition.
Feather dusters are not recommended, as they can catch in small cracks
and dislodge fragments of paint or surface. Remove jewelry and watches before handling your collection.
Make sure buttons, belt buckles, and other accessories will not contact
the object as you handle it. Avoid the presence of food or drink. Keep
work surfaces clean and free of extraneous objects such as keys, paper
clips, tools, and writing implements. 6. Know how to display your objects.
Locate fragile and breakable objects away from areas of
activity where they may be bumped or knocked over. Protect objects in
vitrines or under glass or acrylic. Avoid the use of sticky substances
other than microcrystalline wax to secure unstable inorganic objects on
shelves or other surfaces. Ask a conservator to help prepare mounts for
objects. 7. Know how to store your objects.
Use archival-quality materials sold by companies recommended
by conservators or museum staff. Have your framer use archival-quality
mat board, and insist that archival framing procedures are followed. House
photographs in archival albums or inside inert plastic envelopes. Make
sure to record the significance of each of your objects. Store three-dimensional objects in labeled boxes that are
sufficiently large. Do not overcrowd the objects in a box. Separate them
with neutral pH tissue or with unbleached cotton muslin that has been
machine-washed in hot water (once with soap and once without) and dried.
Place heavier and less intricate objects on the bottom. If textiles must
be folded, pad the folds with tissue to prevent permanent creasing. Protect large, unboxed objects in storage with soft, prewashed
muslin cloth or neutral pH tissue and drape them loosely with polyethylene
sheeting. Framed paintings and framed works of art on paper can be stored
vertically, edges protected with padding, and protected from one another
with archival cardboard. Store metals under dry conditions. To retard tarnish, store
silver wrapped in Pacific silver cloth (available at jewelry and department
stores) or acidfree buffered tissue. Getting Help Professional conservators are skilled in preservation and
treatment techniques that can prolong the life of objects in your collection.
Combining a knowledge of materials science with artistic ability they
work to repair physical weaknesses, diminish chemical instability, and,
to the extent possible, restore an object to its original appearance. Talk with a professional conservator
Conservators are always glad to give you information about
the care of objects in your collection. The recommendations in this brochure are intended as guidance only, and AIC does not assume responsibility or liability.
The American
Institute for Conservation |
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