In Archives, the temperature and relative humidity required for air-conditioning purposes are within the range of

The Correct answer is  20°C ± 25°C and 45 - 55%.

Key Points

• For archival preservation, maintaining an optimal environment is crucial to prevent deterioration of documents, manuscripts, and records.
  • Temperature: 20°C ± 25°C is the ideal range as lower temperatures slow down the degradation of paper, ink, and photographic materials.
  • Relative Humidity (RH): 45 - 55% is maintained to prevent mold growth and paper brittleness. High humidity encourages mold and pests, while low humidity can cause materials to become brittle and crack.
• Importance of Climate Control in Archives:
  • Paper materials require stable conditions to prevent ink fading and acidification.
  • Photographs and microfilms are highly sensitive to temperature fluctuations.
  • Metallic components (such as bindings and fasteners) corrode faster in high humidity.

Additional InformationSome of the Recommendations for libraries to prevent Deterioration of Library Materials:

• Paper-Based Library Material:
  • ​Alkaline substances preserve and strengthen paper.
  • Acid-free materials have a PH of 7.0 or higher.
  • Magnesium carbonate and calcium carbonates are the most common alkaline buffers used to strengthen paper. 
• ​Film Based Media:
  • ​Libraries should isolate and store such material in specially designed storage areas.
  • It is recommended that cellulose nitrate-based films be duplicated onto polyester-based films, which are known as safety films.
• ​Magnetic Media:
  • ​Handle tapes and diskettes minimally, ensuring cleanliness and prompt return to their boxes after use.
  • Maintain equipment as per manufacturer's guidelines, clean tape paths regularly, and protect from dust.
  • Creating backup copies is advised for safeguarding valuable data.
• Optical Media:
  • ​Handle CDs with care, avoiding bending or touching the surface with sharp objects.
  • Refrain from leaving them in disk drives or applying labels, as these may cause damage.
  • Use non-abrasive methods for dust removal and store in acrylic cases or closed storage for protection from scratches, light, and humidity changes.
• Heat, Temperature, and Relative Humidity:
  • ​ It is recommended to maintain a constant room temperature of 20- 25 degrees Celsius and relative humidity of 45-55%
• ​Light:
  • ​Do not expose the material to direct sunlight. Keep the lights switched off in the storage area, when not in use.
  • The light must be kept as low as possible in storage, reading, and display areas.
  • Fluorescent tubes, which emit ultraviolet rays, should be fitted with UV filters.
  • Use window blinds and heavy curtains to control direct sunlight from outside.