Successful long-term and short-term paper storage depends on a stable environment with little or no fluctuation in temperature or humidity. Without this paper can be susceptible to deterioration. High temperatures can cause mould, discolouration and moisture-loss leading to curling. Low relative humidity can cause static build up, sticking and print distortion. Whether storing stacks of unopened paper or important handwritten or print documents, creating the right environment could significantly improve paper preservation.
An temperature of between 18 to 22 degrees Celsius (64 to 72 Fahrenheit) is ideal for paper-storage. Temperatures both lower and higher than this can cause significant and irreparable damage. Do not store paper near to such sources of heat as fireplaces, heaters, heating pipes or in direct sunlight. Sunlight can also cause fading and colour deterioration. Storing paper in basements or attics is not ideal as temperature can fluctuate greatly in outer areas of a building. If possible, store paper near the centre of a building where the temperature remains more stable.
Relative humidity range
The optimum range of relative humidity for paper preservation is 45 to 60 per cent. Humidity is relative as air can hold varying levels of water at different temperatures. Relative humidity is the percentage of water in the air at a specified temperature. Paper responds to the amount of moisture in the air so it is important to get this right to avoid damage.
If the air is too dry, moisture will be drawn from the surfaces, causing the paper to curl. When humidity is low, a build up of static can occur, causing papers to stick together. Achieving this range of humidity can be difficult, however. Relative humidity can be monitored with a hand-held hygrometer, a device that detects the amount of moisture in the air. Dehumidifying machines can help to regulate and stabilise humidity. Do not store paper in areas in which moisture is present, such as bathrooms, kitchens or cellars.
- Relative humidity re-examined; David Erhardt and Marion Meckenburg; 1995
- Canada Mortgage and Housing Corporation: Measuring humidity in your home
- Getty Images