It's not hard to find out how you should store books. Just Google "how to store books". Metal or sealed wood shelves, 50% humility, 60-75 °F, keep that constant, keep away from light, don't store in bags... But lets assume that some of these aren't obtainable. How, then, would one go about storing books.

Curerently, my climate controls aren't especially good. In the winter the temperature ranges from mid 50's to 70 °F, and in the summer, mid 60's to mid 80's. That's in an 8 hour period The land lord doesn't seem to think there is anything wrong with the HVAC and I can't install a window unit. I don't know what the humidity is, but as I type this, I am not comfortable.

My books include mass market paper backs, text books, hard covered books, collectors edition books (mostly Eston Press), trade paper back American and Japanese comics, and a handful of single issue comics. All of the American comics are of the modern sort, printed on pretty decent paper. I don't own any of the older, cheaper kind.

These are stored on cheap plastic veneered composite board constructed book shelves. These shelves are sufficiently old that I assume any solvents should have mostly dissipated. I have my more expensive books in open zip lock bags. I know that CLOSED zip locked bags are bad due to trapping humidity, and encouraging mold growth, but I also assume that an open bag should slow the rate at which humidity, and to a lesser degree temperature, changes. Even more valuable ones (anything worth more than $100) are also loosely wrapped in bubble wrap. I have a few Easton Press books still in their original manufacture's shrink wrap, which has small holes. my individual issues are bagged and boarded.

So, as for the question in this post:

  • What should I do to help protect these books?
  • Have I made any invalid assumptions? For example, are my book shelves an issue, or the zip locks?
  • Also, what would you guys suggest to help mitigate the potential damage caused from a the inconsistent, and occasionally warm/humid environment where I'm living (second floor)?

So much of what I've found is geared towards what is best, but "best" isn't always an option.
Alternatively, am I already doing everything I should do under my restraints?

PS: I completely forgot that I own a dehumidifier, something which neither the land lord nor neighborhood council will complain about. That's one fewer issue. I just moved here and completely forgot about it. I'll dig it out, but humidity is probably the thing I'll have to worry about most.

  • 3
    My biggest concern would be the "50% humility" requirement. I never get that high. :)
    – James
    May 3, 2017 at 14:07
  • Are you sure you're not overcomplicating things? I've had books and comics for a few decades without any special precautions, and they still look nice...
    – holroy
    May 7, 2017 at 8:49
  • @holroy sometimes, it's not enough to have a lawn, mowing it personally may be a bother not worth a lot of people's whiles, but then there are a few that mow the lawn AND make sure it's getting all the right nutrients, and exact amount of water. Document conservation is a valuable hobby specially considering that we are unwittingly creating an electronic dark age as we speak, since bit-rot and electronic document decay is even worse than regular document decay
    – hlecuanda
    May 10, 2017 at 22:05

2 Answers 2


Know thy enemy

Your books worst enemy is of course, humidity. Humidity is also conditio sine qua non for the dreaded mold that will happily munch on the cellulose leaving behind not much in the way of a cultural legacy for future humans enslaved by Skynet. The details provided on your question indicate that temperature may not be a concern, since it falls within the range recommended by the Northwest Documentation Center, and endorsed by the Library of Congress. These resources also point to an ideal relative air humidity between 30% and 50%.

However, the most important factor is the stability of the environment rather than the actual specs chosen for such environment, as rapid changes in environmental conditions are the main culprit of document deterioration, as the rate of most chemical reactions affecting cellulose substrates is doubled with every 10°C of temperature increase. High temperature combined with a high humidity concentration will encourage insect activity and mold growth, in addition to chemical deterioration.

Chose your battle wisely.

Since the temperature problem appears to be out of your control, and the temperature variations due to seasonal changes fall within the range of the above recommendations, my advice is to focus your efforts on the variable you can control vis-a-vis: humidity.

Size up the monster.

Peace of mind regarding the environmental conditions of your collection can only be achieved by properly measuring this conditions. You may wish to acquire a hygrometer which may not be as expensive an instrument as one may think, (around USD$ 10.00 at the time of writing) and can be considered chump change compared to the value of your collection.

In order for the hygrometer to be effective you may wish to arrange your collection within an enclosed bookshelf, with the books and documents tightly packed as space allows, per the recommendations cited above.

The idea is to avoid controlling the humidity of your entire apartment, and be able to measure humidity conditions within the critical document storage environment. It doesent need to be airtight, just restrict the airflow enough to keep humidity out and optimize the performance of any dissecant or hygroscopic material you choose to control the environment within.

Select your ideal arsenal for battle

To get rid of humidity, and thus making the acquisition of an expensive fungicide a matter of redundancy, enclose a canister of a highly hygroscopic substance along with your dead-tree books collection, once this is done, any humidity within your bookshelf ends up getting sucked and sequestered by such substance, leaving a nice, dry, mold-unfriendly measured environment once you close the lids.

For this purpose, I recommend the use of silica gel packets that come with most electronic device or apparel packaging. However, since your collection seems rather extended, this alternative may prove impractical, unless you've been collecting the silica gel on your purchases for the last few years.

silica gel

These can be purchased in bulk, (around USD$ 5.00 for 100 1g packets on Amazon, at the time of writing) and have the advantage of coming in an unobtrusive, small paper package that will allow moisture in, but won't let the silica gel spread all over.

A cheap alternative is to roll your own. One of the most hygroscopic substances available in the cheap is a mineral called zeolite which is the main ingredient of most brands of commercial non-clumping cat litter sand.

Just build your canister for zeolite using an average coffee filter for the purpose. It's porous enough to keep the zeolite in the envelope while not diminishing it's affinity for water in any discernable way.

Wait!, how can i make sure i don't over-do it?

Glad you asked, since future Skynet enslaved humans will be very disappointed if their hope for cultural legacy turns to dry dust in their hands upon touching it.

The question here is how much desiccant is about right to keep relative humidity between 30% and 50% The quick answer is: trial and error. That's why we're sizing up the monster and measuring the environment with the hygrometer we wisely invested in. Most silica gel manufacturers recommend this approach, but if we're sparing no expense, then purchasing desiccant canisters certified conformant to military spec MIL-D-3464E is the way to go.

Be advised, though, that MIL-SPEC certified materials will cost anywhere between 200% to 500% more than your garden variety non-certified consumer grade materials. What you're buying with that cost difference is the certainty that the material will perform as stated on the specification with minimal deviation (again, as allowed by the same spec)

The specification defines a unit of dissecant, as the amount of material that will absorb 3g of water at 20% Relative humidity and 6g of water at 40% relative humidity, for bulk material; and 2.85g and 5.70g of water respectively for bagged materials.

Thus you can calculate the amount of dissecant units required given your environmental conditions. Note however that how much material is in a unit of dissecant depends on the specific materal, for military grade silica gel, a unit is about 50g in a 4.5" x 3" sealed porous paper bag

Or just use this handy calculator


In short:

  • Get a hygrometer
  • Restrict airflow to your collection (pull a plastic cover over your bookshelf)
  • Place a canister of silica gel or zeolite within the bookshelf
  • Keep books tightly packed
  • Monitor the humidity on the bookshelf, adding silica gel as required
  • Periodically "regenerate" the silica gel per manufacturer instructions
  • Just toss a silica gel baggie on your zip-loc enclosed documents, and change from time to time
  • Don't feed skynet! Stop training it's algorithms by avoiding the use of Facebook like the plague (kidding)
  • 1
    For a closed bag, is there a concern that the zeolate and/or silica may take it TOO far? I also read that too dry and hot will desecate the books, which is almost as bad as they turning into something's dinner.
    – Nero gris
    May 3, 2017 at 19:20
  • @Nero gris, I've amended my answer to address your concern. You're right, it's possible to over-do it, but the most cost-effective solution ends up avoiding zip-locs in order to effectively measure humidity, and trial-and-error on the amount of desiccant used. Even vendors endorse this approach.
    – hlecuanda
    May 4, 2017 at 1:53
  • 1
    Okay. That's a hell of an answer! Kudos! Those humans brave enough to learn to read in the future will thank you for helping me!
    – Nero gris
    May 4, 2017 at 14:22

The novel Lucifer's Hammer by Larry Niven and Jerry Pournelle had a scene where a character "stored" a collection of books that would be important to the future (re)development of an industrial civiliation -- he was concerned about theft, as well as environmental destruction, because of the impending impact of fragments of a comet.

His solution was to spray each book thoroughly with insecticide (to kill bookworms, termites, etc.), bag each book in four layers of zipper bags, then push them down into the contents of a septic tank. After he was done he put the cover back on the tank.

You needn't go so far as the septic tank, but the insecticide and bags aren't a bad idea. The humidity inside the bag won't change after it's sealed, the bug spray will prevent insect depradation, and storing the books in a deep freeze after sealing will prevent mold growth and similar issues that the bug spray won't solve.

This is more of a long term solution -- and, of course, remember to do the spraying/bagging outdoors.

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