TREATING DAMAGED ARTWORK
Here are some of the ways your artwork might become
damaged and some advice on how to treat these issues.
All light causes irreversible damage to artworks. The extent of
the deterioration depends on the type of light source, its
intensity and the length of exposure. Light damage is
Natural light is an extremely intense source of energy and
contains ultra-violet (UV) radiation. Most artworks are composed of
organic materials making them especially vulnerable to UV
wavelengths which cause embrittlement and discolouration.
However the visible light spectrum is the main cause of fading to
colours rather than UV.
The effect of artificial light is less acute, although
fluorescent tubes do emit substantial amounts of UV. Incandescent
light sources are the least harmful, but the heat they generate can
still, like sunlight, impair an artwork.
Usually the most obvious effect on a picture exposed to too much
light is the change that occurs to its colour.
Varnishes on paintings can darken altering tonal values.
Watercolour pigments may fade dramatically in a very short
period of time.
The canvas or paper support can become increasingly discoloured
and brittle as the light chemically changes the structure, making
it weak and inflexible. Light damage is not limited to 'old'
artworks. Modern pigments, canvas, colour and black and white
photographs can fade or change just as quickly.
What to do
- Restrict the amount of light and the length of exposure time
for any artwork.
- Keep all artworks away from direct or strongly reflected light.
If sunlight is falling on the picture, the picture should be
- Reduce the light levels by closing the curtains. Windows can be
coated with a clear UV film.
- Use low-wattage incandescent bulbs in preference to the
- Never spot-light a picture with a bright light source.
- Glazing will provide some protection against UV.
- Consider having a copy made and hang in place of the original
if the picture is particularly vulnerable, especially in the case
Relative humidity and
Most organic materials used to make pictures are hygroscopic,
meaning they will absorb or release moisture in response to changes
in the environment.
Relative humidity is a measurement of the amount of moisture in
the air. As the temperature changes, so does the amount of moisture
the air can hold. Extremes and fluctuations of temperature and
humidity are the most damaging, since they set up a cycle of rapid
expansion and contraction, which places the artwork under stress.
It is important to control both in order to minimise the
Mould growth will flourish in high levels of temperature and
humidity. It creates disfiguring, sometimes permanent stains,
attacks the surface of the work, and can digest paper, canvas and
As artworks expand and contract in response to the amount of
moisture in the air, internal stresses are created. This can lead
to flaking and cracking in paint layers and photographic emulsions,
distortions and even splitting and tearing of support material.
High levels of humidity and temperature can increase the rate of
chemical reaction, effectively speeding up the rate of
deterioration of any artwork. Conversely, in very low levels of
humidity, paint layers and support materials can become
Insects and rodents flourish in a warm, damp climate and enjoy
nothing more than chewing their way through your valued
watercolours and photographs.
What to do
- Avoid hanging pictures in damp rooms, on outside walls, or near
water sources, such as bathrooms and kitchens.
- Never display pictures above or near electrical equipment,
heaters, radiators and fires. Some types of gas heaters will
generate moisture and form damaging condensation.
- Do not leave artworks in unventilated areas such as
- Check artworks regularly for any sign of mould growth.
- Use dehumidifiers to stabilise/lower humidity levels.
Dust, dirt and
The mild, wet climate in New Zealand provides the perfect
breeding ground for insects and mould.
Insects will attack artworks in a variety of ways, resulting in
a range of damage. This may be visible as small holes restricted to
a frame or stretcher or spot stains on the surface of an artwork.
In the case of artworks on paper or photographs, however, extensive
losses to the image and support are quite common.
While insects and rodents will thrive in an undisturbed dark,
dusty environment, mould requires a damp atmosphere.
Dust is always present in the air. In direct contact with the
surface of artworks, it is not only disfiguring, but also
Silverfish will eat paper and, in the case of photographs, the
gelatine layer which comprises the image.
Borer can destroy frames and stretchers on paintings internally.
As a result the damage is not often recognised until too late.
Flyspots, commonly seen on the surface of paintings, are small
dark deposits left by flies. The can etch into paint and varnish
layers, permanently disfiguring the image.
The brown spot stains on watercolours are known as 'foxing'.
They are usually caused by metallic impurities in the support paper
or backboard, and are often associated with surface mould
What to do
- Keep the artwork in a clean environment. Handle as little as
possible, always with clean hands.
- Ensure the artwork is correctly framed.
- Maintain a reasonable air circulation around the artwork -
avoid hanging pictures on damp walls or storing in closed
- Inspect the front and back of an artwork regularly to check for
any insect infestation or mould growth.
It pays to have artworks correctly framed. Framing reduces the
possibility of damage from handling and provides protection against
the environment. Because an artist will often choose the original
frame to complement the artwork, the aesthetic impact of
alterations should be carefully considered.
Acids damage paper. When cheap boards, glues and tapes are used
in direct contact with paper, they can make it acidic, discoloured
and unstable. Such materials are often very difficult to remove,
leaving the artwork severely damaged and permanently stained.
If paintings on canvas lack a backboard, they may suffer from
impact damage and an accumulation of dirt on the reverse.
Glazing is useful protection for both paintings and works of art
on paper, but can adhere to artworks if in direct contact.
What to do
- Use perspex or glass as glazing to protect the artwork. Matt
glass does not have any special light filtering properties. Frames
should always have a backboard.
- Separate the artwork from the glazing by either a window mount
or spacer. Never adhere anything to the front or back of the
- Always insist that the framer uses acid-free, conservation
standard materials (e.g. conservation board which is buffered with
calcium carbonate and is alkaline).
- Ensure the framer secures the painting firmly in the frame with
brackets. Never use nails.
- Strong hanging fixtures are essentials. Hang the painting with
thick nylon cord.
- Never attempt to 'clean' or 'repair' a picture. There is
nothing you can safely do - often the worst type of damage results
from the best of intentions.
- If in doubt, consult a conservator, registered with the New Zealand Conservators of
Cultural Materials, who will be only too happy to provide a
Why do artworks
Regardless of the value of an artwork, it is often irreplaceable
to its owner. It is vital that paintings, works of art on paper and
photographs be cared for if they are to last. Many factors
influence the permanence of artworks.
Sometimes there are inherent problems due to the quality of the
paint, canvas or paper used; alternatively a combination of
incompatible materials in the artwork may promote instability. More
often, careless handling, poor framing and inappropriate methods of
display and storage contribute the most damage.
It is important to consider the environment in which you keep
your artworks. Our everyday climate has levels of light, heat,
moisture and pollutants which can produce destructive chemical and
physical reactions within works of art.
Although it is not usually possible to prevent deterioration
completely, modifying the environment will help to slow down the
process of decay. This is good conservation. By taking a few simple
steps now, you can significantly aid the preservation of your art
works. Remember, not all damage is reversible - prevention is
always better than cure.
Conservation Services at the Auckland Art Gallery offer advice
and practical treatment for paintings and works on paper. Trained
conservators are also available to survey both private and