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Collection care: environmental factors


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  • 1. Collection Care:Environmental Factors Valinda S. Carroll
  • 2. Agents of Deterioration High Temperature Humidity Light Pests and Fungi Handling Air Pollution
  • 3. Temperature and HumidityTraditionally, museum climate controlhas been based on human comfort, thecapacity of the heating and airconditioning system, and the limitationsof the building.
  • 4. High TemperatureHigh temperatures may  Causes cross-linkingdamage artifacts in (makes materials becomeseveral ways brittle)  Causes chain scission (makes materials weaker)  Makes materials expand (causes splitting and delamination)  Lowers relative humidity (causes shrinkage and splitting)
  • 5. High HumidityExcessive humidity is  Accelerates chemicaldamaging to art and damagehistoric 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 ThermohygrometerAdvantages•Displays relative humidity•Displays temperature•Portable•Easy to use•Does not require additionalequipment or supplies•Inexpensive
  • 8. Handheld ThermohygrometerDisadvantages•Does not record overtime•Does not store readings•May be inaccurate, anddifficult to calibrate•User must purchasebatteries
  • 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 calibratingWet 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
  • 12. Recording Hygrothermograph
  • 13. Recording hygrothermograph Advantages •Shows temperatureRedtemperatureline
  • 14. Recording hygrothermograph Advantages•Shows temperature•Shows humidityBlue humidityline
  • 15. Data loggerAdvantages  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 loggerDisadvantages  Requires batteries  Inexpensive models cannot be read without computer  Inexpensive models must be downloaded individually, by hand
  • 17. Humidity CardAdvantages • 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 CardDisadvantages • Imprecise •Not durable •Does not record over time •Cobalt blue salt is toxic (orange humidity cards are non-toxic)
  • 19. Temperature CardAdvantages•Inexpensive•Easy to use•Portable•Small enough to fit into frame,exhibit case, or shipping crate
  • 20. Temperature CardDisadvantages•Imprecise•Does not record over time•Does not generate permanentdocumentation•Not durable
  • 21. Effects of LightLight is necessary for exhibits, but excess exposure can lead to many problems Fading Yellowing Weakening and breakage of fibers and polymers
  • 22. Light Monitoring Tools Blue Wool standard Light meter UV meter Light data logger
  • 23. Blue woolAdvantages•Blue wool swatches provide a qualitativeassessment of fading.•They are compact and portable enough to use inframes or exhibit cases.•A spectrophotometer or colorimeter may be usedto detect blue dye fading before it becomes visibleto the human eye.
  • 24. Blue woolDisadvantages•Blue wool standard swatches only showfading; they cannot indicate future fading orother types of damage.•The extent and rate of fading vary dependingon the spectrum of the light source. Blue woolstandards were designed for use with sunlight,not artificial lights.
  • 25. Light MeterAdvantages•Can measure output fromwindows and lamps•Can measure incidentlight falling on surface ofobject•Portable•Can be read instantly•Can show lux or foot-candles(1 foot-candle~ 10 lux)
  • 26. Light MeterDisadvantages•Does not generatepermanent record•Requires batteries
  • 27. Ultraviolet MeterUltraviolet radiation is expressed relative to the overall light level inlux. The maximum recommended amount of UV is 0.375microwatts per square centimeter, measured at a light level of 50lux (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
  • 30. Biological Agents  Fungi  Insects  Rodents
  • 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 firesUse electric or battery-operated candles and fireplace inserts to avoid unnecessary risks to your collection
  • 38. Outdoor Pollutants  Car exhaust  Factories  Forest fires
  • 39. Outdoor Pollutants  Keep windows and doors closed  Change filters in HVAC system  Store artifacts in protective enclosures
  • 40. Volatile Organic CompoundsRegular Paint Low VOC Paint
  • 41. Off-gassingProtect artifacts fromcontact with materials  Unstable plasticsknown to release harmful (cellulose acetate,gasses cellulose nitrate, etc.)  Unsealed wood (interior grade plywood, oak, etc.)  Paints or cleaning materials of unknown or untested composition
  • 42. Volatile acetic acid (cellulose acetate film deterioration) moderate severe severe slightControls
  • 43. Oddy Test
  • 44. Hidden dangers Ozone Photocopiers and laserprinters emit ozone. Keepsuch machines in officespaces separate fromfrom collections storageareas.
  • 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)
  • 47. Protective Housing Materials Activated charcoal and Zeolite-containingpotassium permanganate alkaline rag board sheets
  • 48. Protective Housing Materials Capacity to counteract pollutants not easily determined Shelf life not easily determined More expensive than traditional housing materials
  • 49. END