Humidity in the 30s - safe for long term storage? 1 1

[jabats]

For those of us in the Midwest or where the winters are cold and dry, our homes may have 3-5 or more months of humidity in the 30-39% range.

I know that humidity >50% is bad for comic storage; what about a space that is consistently dry (30-39%)?

Note: I am mainly concerned with high value, CGC-slabbed books.

[jabats]

I have read on the forums and elsewhere that 40-49% is the optimal RH (not everyone agrees).

but interestingly the ALA recommends 30-40% RH:

http://www.ala.org/alcts/sites/ala.org.alcts/files/content/_MeltzerBkmk16.pdf

[jabats]

Library of Congress recommends 35% RH for comic book storage.

https://www.loc.gov/preservation/care/comics.html

” Good storage is especially critical to the preservation of acidic paper materials. Guidelines for good storage: 

• A cool (room temperature or below), relatively dry (about 35% relative humidity), clean, and stable environment (avoid attics, basements, and other locations with high risk of leaks and environmental extremes) 
• Minimal exposure to all kinds of light; no exposure to direct or intense light
• Distance from radiators and vents
• Supportive protective enclosures*”

[JollyComics]

9 hours ago, jabats said:

A cool (room temperature or below), relatively dry (about 35% relative humidity), clean, and stable environment (avoid attics, basements, and other locations with high risk of leaks and environmental extremes)

Two years ago, I bought about 45 SA books from the estimate sale and asked them where the books were stored. They found them in the attic even the family members didn't know about it.  I assumed those books spent over 40 years inside the attic. That explained why the cover edges were brittle and most spines were completely split even the water damages too. All pages are cream - some light tan.

[newshane]

I think the 30s is probably ideal, actually. 

I would certainly rather the paper be too dry than too damp!

[The Lions Den]

Expansion and contraction are constant factors that need to be reduced as much as possible. Cool, dry, and dark, with relatively low humidity, and stored in archival storage products. I've seen books stored this way for decades that have suffered little to no degradation...