Solar radiation...alias: Sunshine...alias: ultra-violet
Direct sunlight is very, very hard on any mat,
but especially non-conservation
matboard. Fading of the mat color can occur extremely
quickly in late spring, summer and early fall when the
sun is high, and is still a major concern at any time
of year. The core of the mat will go pre-maturely brown
with high exposure. The artwork itself is also at risk,
especially lower quality prints. Photos printed by high
volume retailers can fade in a couple of days of strong
sun. Photos from higher quality retail photo finishing
shops are often of much higher quality, but will still
fade with enough exposure to direct sunlight.
The cure is easy. Never allow framed art of any
type to be exposed to direct sun. Period. Unfortunately
florescent lighting has some of the same harmful qualities
of sunlight, though to a lessor extent. If the artwork
will be exposed to high volumes of this type of lighting,
consider purchasing conservation quality glass. It is
available at most glass shops and in custom framing retail
stores. Prepare to be shocked, as the price is very high.
Regular and non-glare glass afford some UV protection,
but not much. Acrylics, (plastic, plexiglass, etc.), have
inherent properties that reduce some ultraviolet light
but cannot be considered conservation quality.
High relative humidity or excess moisture.
Definition of Relative Humidity: The amount of
water vapor in the air relative to the amount of water
vapor the air is capable of holding at a given temperature.
If the temperature goes down, the relative humidity will
go up. If the temperature goes down enough, the air cannot
hold the moisture and condensation occurs.
moisture in the air will penetrate the framing package,
causing condensation. The problem is most apparent when
a slight bit of cooling allows water vapor to condense
on the glass. Any adjacent surface will suffer water damage.
If a mat is present at least the artwork is protected
from direct damage, which is an excellent reason to use
mats. Most artwork will tend to become wavy.
Under normal conditions this should not be a big
problem. If the temperature inside is warmer than outside,
the relative humidity should remain below the danger point.
Unheated areas can sometimes produce relative humidities
at or near 100%, and certainly bathrooms and kitchens
can be a problem. Shipping artwork, or allowing it to
be transported in vehicles during periods of high heat
and humidity can be deadly if care is not taken. Moisture
absorbers can be packed with artwork to help protect it.
Artwork in kitchens and bathrooms can be sealed to some
extent by caulking the edges, but this is only a partial
help. Never hang valuable artwork in a high humidity area.
Most materials shrink or expand with high heat,
and the framing package is no exception. Leave a mat out
in an area of rising temperature and it will cup, sometimes
substantially. The level of relative humidity will also
contribute to this effect. High heat combined with excessive
humidity can cause artwork to become glued to glass, especially
in the case of photos. Once this occurs, the damage is
permanent. Use mats to keep the artwork from touching
Generally, high heat in a home should not be a
big problem, especially in dry areas. Transporting artwork
can be tricky. Never leave it in a trunk during hot or
humid weather, and even the interior of a vehicle can
be much too hot. Get it home to a safe environment as
quickly as possible. When shipping artwork make sure it
will not be subjected to high heat.
Do not get paranoid about exposing framed artwork
in normal settings. Hanging from a wall a few feet from
either the floor or ceiling protects it from extremes
of temperature and humidity within the house. Be sure
the house is never left unheated in cold and damp weather,
and never leave it outside or in vehicles any longer than
possible. Make sure the sun never sees it directly, and
keep your better stuff away from florescent lights. Use
conservation glass or acrylic for especially valuable
or valued pieces.