2. Agents of Deterioration
High
Temperature
Humidity
Light
Pests and Fungi
Handling
Air Pollution
3. Temperature and Humidity
Traditionally, museum climate control
has been based on human comfort, the
capacity of the heating and air
conditioning system, and the limitations
of the building.
4. High Temperature
High temperatures may Causes cross-linking
damage artifacts in (makes materials become
several ways brittle)
Causes chain scission
(makes materials weaker)
Makes materials expand
(causes splitting and
delamination)
Lowers relative humidity
(causes shrinkage and
splitting)
5. High Humidity
Excessive humidity is Accelerates chemical
damaging to art and damage
historic artifacts Promotes swelling,
distortions, and
delamination
Encourages mold growth
Increases insect activity
(especially combined with
high temperature)
Warped floor tiles
6. Measurement Tools
Handheld Recording
Thermohygrometer Hygrothermograph
Thermometer and Electronic Data loggers
Psychrometer Temperature and
Humidity Indicator
Cards
7. Handheld
Thermohygrometer
Advantages
•Displays relative humidity
•Displays temperature
•Portable
•Easy to use
•Does not require additional
equipment or supplies
•Inexpensive
8. Handheld
Thermohygrometer
Disadvantages
•Does not record over
time
•Does not store readings
•May be inaccurate, and
difficult to calibrate
•User must purchase
batteries
9. Aspirating Psychrometer
•Compares wet bulb
and dry bulb
temperature to find
dew point and relative
humidity
•Contains light to
make thermometers
easier to read
10. Aspirating Psychrometer
Uses a fan to evaporate
moisture from cloth on wet
bulb
Can assist in calibrating
Wet bulb other instruments
More reliable and easier to
use than sling
psychrometer
11. Aspirating Psychrometer
• Does not record over
time
• Requires slide rule or
mathematical
calculations
• Does not generate
documentation
15. Data logger
Advantages Records over time
Small enough to fit into
exhibit case or packing
crate
Data can be loaded into
standard spreadsheet
software to generate
reports
May be less expensive
than hygrothermograph
16. Data logger
Disadvantages
Requires batteries
Inexpensive models
cannot be read without
computer
Inexpensive models
must be downloaded
individually, by hand
17. Humidity Card
Advantages
• Small enough to fit into frame,
exhibit case, or shipping crate
•Inexpensive unit cost
•Does not require batteries
•Does not require computer or
slide rule
18. Humidity Card
Disadvantages
• Imprecise
•Not durable
•Does not record over time
•Cobalt blue salt is toxic (orange
humidity cards are non-toxic)
21. Effects of Light
Light is necessary for exhibits, but excess
exposure can lead to many problems
Fading
Yellowing
Weakening and breakage of fibers and
polymers
23. Blue wool
Advantages
•Blue wool swatches provide a qualitative
assessment of fading.
•They are compact and portable enough to use in
frames or exhibit cases.
•A spectrophotometer or colorimeter may be used
to detect blue dye fading before it becomes visible
to the human eye.
24. Blue wool
Disadvantages
•Blue wool standard swatches only show
fading; they cannot indicate future fading or
other types of damage.
•The extent and rate of fading vary depending
on the spectrum of the light source. Blue wool
standards were designed for use with sunlight,
not artificial lights.
25. Light Meter
Advantages
•Can measure output from
windows and lamps
•Can measure incident
light falling on surface of
object
•Portable
•Can be read instantly
•Can show lux or foot-
candles
(1 foot-candle~ 10 lux)
27. Ultraviolet Meter
Ultraviolet radiation is expressed relative to the overall light level in
lux. The maximum recommended amount of UV is 0.375
microwatts per square centimeter, measured at a light level of 50
lux (about 5 foot-candles).
Ultraviolet (UV) meter
showing 9 microwatts per
square centimeter, a rather
high level.
28. UV-filtering materials
Ultraviolet filtering materials
can be used in windows, light
fixtures, exhibit cases, and/or
frames
•Acrylic (Plexiglas UF, Acrylite
OP, TrueVue Optium)
•Polycarbonate (Lexan)
•Laminated Glass (Schott
Amiran)
•Filtering window films
•Fluorescent tube sleeves
29. Mitigation Strategies
Store collections in closed boxes and
cabinets, rather than open shelves
Close shutters (in historic buildings),
shades, or blinds
Use UV-filtering glazing in frames
and exhibit cases and UV-filtering
sleeves on lights
Hang curtains in front of vulnerable
artwork or drape cloth over exhibit
cases when museum is closed
Use motion detector switches for
gallery lighting
31. Mold Safety
Always wear personal protective
equipment: N95 respirator, gloves,
goggles
Use a HEPA vacuum and a soft brush
( a HEPA or ULPA filter prevents the
vacuum cleaner from filling the air
with microscopic mold spores)
Create a work area separate from
collections storage to avoid cross-
contamination
32. Insects
Many insects are
attracted to food Some insects eat only
eaten by humans one type of material, so
Insects seek shelter it is useful to consult an
in human identification chart
habitations,
especially during
inclement weather
Many insects feed on
starches and
proteins in museum
artifacts
33. Rodents
Rodents are attracted
to food eaten by
humans
Rodents seek shelter in
human habitations,
especially during
inclement weather
Rodents feed on
starches and proteins
in museum artifacts
34. Pest Control Methods
Seal entry points (caulk,
weather-strip, etc.)
Remove food sources and
breeding places
Use outdoor bait stations
to control rodents before
they enter the building
Monitor insect activity
with sticky traps and
pheromone lures
35. Pest Control Methods
Lower temperatures,
possibly to freezing point
Reduce relative humidity
Remove sources of oxygen
(nitrogen or argon chamber,
Ageless™ oxygen absorber)
36. Air Pollutants
Soot and smoke
Outdoor pollutants
Volatile organic compounds
Off-gassing from collections and exhibit
materials
Ozone
37. Open Flames
•Candles generate soot
•Flames in generate
very high heat
•Genuine candles,
working fireplaces, and
cigarette smoking may
lead to fires
Use electric or battery-operated candles and fireplace inserts to
avoid unnecessary risks to your collection
44. Hidden dangers
Ozone
Photocopiers and laser
printers emit ozone. Keep
such machines in office
spaces separate from
from collections storage
areas.
45. Protective Housing Materials
Absorb or adsorb
chemical pollutants
from the air
Thin sheets can be
incorporated into
frames and exhibit
cases
May act as mechanical
barriers to pollutants Plastic films and bags with
Easy to use Intercept ™ technology (finely
divided copper)
46. Protective Housing Materials
Microchamber ™ paper
Bainbridge Alpharag
Artcare ™
Scavengel ™ cloth
Activated charcoal
cloth
Corrosion Intercept ™
films and bags (plastic
impregnated with
finely divided copper)
48. Protective Housing Materials
Capacity to counteract
pollutants not easily
determined
Shelf life not easily
determined
More expensive than
traditional housing
materials