What is the best combination of temperature and humidity for storing library books?

What is the best combination of temperature and humidity for storing library books?

• A. 40-50 degrees; 20-30%
• B. 60-70 degrees; 50-60%
• C. 70-80 degrees; 70-80%
• D. 50-60 degrees; 30-40%

Answer: (B)

Maintaining stable environmental conditions is crucial for preserving books. Paper moisture content follows the surrounding humidity: too much moisture lets fibers swell, promotes mold and pests, and can warp bindings; too little moisture makes paper brittle and prone to cracking. Temperature also matters because warmer conditions accelerate deterioration and microbial growth, while very cold conditions can create condensation problems if humidity isn’t controlled. The best pairing among the options is a moderate temperature of 60-70°F with relative humidity around 50-60%. This balance slows chemical deterioration and mold activity, while keeping humidity high enough to avoid excessive drying but not so high that mold and pests become easily active. The other options push toward conditions that increase brittleness (too dry) or encourage mold and pests (too warm and too humid) or are risky for moisture-related condensation.

Maintaining stable environmental conditions is crucial for preserving books. Paper moisture content follows the surrounding humidity: too much moisture lets fibers swell, promotes mold and pests, and can warp bindings; too little moisture makes paper brittle and prone to cracking. Temperature also matters because warmer conditions accelerate deterioration and microbial growth, while very cold conditions can create condensation problems if humidity isn’t controlled.

The best pairing among the options is a moderate temperature of 60-70°F with relative humidity around 50-60%. This balance slows chemical deterioration and mold activity, while keeping humidity high enough to avoid excessive drying but not so high that mold and pests become easily active. The other options push toward conditions that increase brittleness (too dry) or encourage mold and pests (too warm and too humid) or are risky for moisture-related condensation.