Storage of cards & relative humidity

[TipTopBread]

Can someone provide me with the best range of RELATIVE HUMIDITY for the storage of baseball cards? I have been asked by another collector who stores cards in his home, he indicated he has several rooms in the home for storage. However the rooms vary to some degree in the % of RELATIVE HUMIDITY. I quite never thought about it, since my storage is within a safe deposit box at a bank. I just told him that I would not store them in the highest RELATIVE HUMIDITY room, but I was not sure if a LOW RELATIVE HUMIDITY room was the best answer. I had thoughts it may tend to have a drying out effect on such cards. Can anyone respond, it would be greatly appreciated. Thank you!!! P.S. most cards are slabbed.

[drcy]

The lower the humidity the better. Dry is good. I think humidity + heat is only a major concern if you are in South Carolina, Florida or store your items in the boiler room. I assume most people here live in household conditions that are fine for cards.

[Bestdj777]

Here is a note from the Library of Congress:

Treatment: The Top Treasures are stored in a cold storage vault in the Conservation Division. Each treasure is housed in a protective enclosure. The lack of oxygen and the cold temperature and stable humidity inside of the vault extends the life of these documents by several hundred years. The temperature in the vault is 50 degrees F. The relative humidity is 50%. These are ideal conditions for paper documents.

http://www.loc.gov/preservation/conservators/bachbase/bbcmanus/bbcmanus2.html

I am assuming he cannot regulate the temperature that well, and not sure how the humidity correlates. My best advice is to throw some silica packets in with his cards just to be safe. They are available in bulk on eBay and I believe Amazon. I use them in my firesafe just to be cautious.