blogis librorum. A blog about books. Rare books.

Regardless of where you live, maintaining the ideal environmental conditions in your personal library presents specific challenges. Conservation of rare books requires keeping your library at a certain temperature and humidity.

Paper products are hygroscopic, meaning that they easily absorb and release moisture. This means that your rare books respond to even the most minute variations in temperature and humidity by contracting and expanding. If temperature and humidity aren't controlled over time, visible damage like warped covers and flaking ink can occur. The paper itself also begins to break down more rapidly.

While institutions may have the budget for expensive HVAC systems and other equipment, there are several simple, cost effective methods that you can use at home.

• Keep your AC set to a consistent temperature. Fluctuations in temperature can accelerate deterioration. Consider keeping your home at a temperature where you'll be relatively comfortable throughout the year.

• During the winter, resist the urge to turn up the heat. You'll save money on utilities and protect your rare books. Excess heat can be destructive and it can raise humidity beyond acceptable levels.

• Store your books in a room without doors that open to the outside. Outside air not only contributes to temperature and humidity changes; it is also more likely to contain dirt and dust, which can damage your books.

• Don't open windows in your personal library. It may be tempting to do this if a room gets too warm in the winter, but you'll reduce the humidity of the room—already difficult to maintain during colder months.

• Remove books from direct sunlight. While short-term exposure isn't the end of the world, long-term UV exposure will fade the dust jackets and covers of rare books and accelerate decomposition.

• Place your books well away from radiators, vents, and other areas that may be subject to exceptionally high or low temperatures. You can block heat from radiators by placing an aluminum-covered wallboard in front of the radiator.

• Know your materials. Parchment and vellum, for instance, require different environmental conditions. Group items that contain similar materials together and place them in locations that have conditions closest to their ideal.