Humidity And Your Documents

The most frequent question I get is: How can I preserve and save my family documents.  I will often ask questions to try and figure out the current condition to make recommendations.  My basic recommendations are:  1. Unfold the documents and store flat.  Documents tear along fold lines.  Unfolding these documents, will take the stress off of the fold.  2. Do not store archival material in direct sunlight.  The UV light will cause the documents and photographs to fade.  3.  Do not store artwork, documents or photographs on outside walls.  Outside walls have the most contact with outdoor temperature fluctuations and will expand and contract depending on the weather conditions, causing your material to expand and contract.   4.  Do not store your documents in attics or basements, because of the lack of control over temperature and humidity and risk of flooding.  Too much humidity can cause mold growth and too little humidity can make archival material brittle.  Both accelerate the deterioration of archival material.   5.  If your documents are rolled and maintain their tube-like shape, do not unroll them.  Unrolling them will cause them to break at stress points along the roll.  The documents will need to be humidified and once relaxed, can then be viewed.

Rolled Document
This is a rolled document before humidification.  You can see where the document has started to tear along the roll.  You can also see where the donor, at one point, tried to tape the tears to keep the document from breaking.  Please do not tape your documents.  The adhesive will add to the deterioration of the document.
Broken Photograph
This photograph has broken apart along the fold and is now in multiple pieces.  Curiosity got the best of the donor of this image.  When the first section broke off, he continued to unroll the image to see it in its entirety.  As a result, the image is in multiple pieces and cannot be put back together.

 

 

 

 

 

 

 

 

 

 

When I started working here, I made the recommendation that documents could be humidified in a steamy bathroom.  After a couple of long hot showers, the documents would begin to relax and then could be better handled.  I made that recommendation, because I had tested it in my bathroom when I was living in New York.  It worked great; until this past winter.  The Henry Janssen Library is climate controlled, up to a certain point.  During the winter the boiler is turned on and, in theory, I should be able to build up humidity in our humidifier.  We use the double garbage can method, with distilled water.  However, this past winter, nothing I did could get enough humidity into the chamber to humidify some tightly rolled documents.  As a last resort, I took them home to use my trusty bathroom method.  The bathroom humidification chamber didn’t work and I ended up bring the HJL’s humidification system home and finished the project.

I learned that the effectiveness of building up enough humidity in a bathroom, in order to hydrate documents is determined by the size of the bathroom.  My bathroom in Gibraltar is twice the size of my old one in New York and has a window.  Since the room is larger, it takes more steam to fill and less time for that steam to dissipate than in a smaller more compact space.   The documents were not getting enough time to soak in the moisture.   I forgot history preservation is also about physics.

In an ideal setting, including the Henry Janssen Library, all archival material would be stored in an area lower than 68 degrees Fahrenheit with humidity between 30-50% with very little fluctuation.  Unfortunately, the recommended storage conditions are not the ideal living (or researching) conditions.  Fortunately for the “Do-It-Yourselfers” following the recommendations above will set you on the track toward preservation.

For more information on how you can humidify your documents, please check out this article “Practical Considerations for Humidifying and Flattening Paper” by Stephanie Watkins, found at: http://cool.conservation-us.org/coolaic/sg/bpg/annual/v21/bp21-15.pdf, or other resources through Google.

The Northeast Document Conservation Center states that temperature and humidity control is vital to the preservation of archival material because unacceptable levels cause the deterioration of the material.… Heat accelerates deterioration: the rate of most chemical reactions, including deterioration, is approximately doubled with each increase in temperature of 18°F (10°C). High relative humidity provides the moisture necessary to promote harmful chemical reactions in materials and, in combination with high temperature, encourages mold growth and insect activity. Extremely low relative humidity, which can occur in winter in centrally heated buildings, may lead to desiccation and embrittlement of some materials.  …Fluctuations in temperature and relative humidity are also damaging [because] …they respond to diurnal and seasonal changes…by expanding and contracting. Dimensional changes accelerate deterioration and lead to such visible damage as cockling paper, flaking ink, warped covers on books, and cracked emulsion on photographs. – www.nedcc.org/free-resources/preservation-leaflets/2.-the-environment/2.1-temperature,-relative-humidity,-light,-and-air-quality-basic-guidelines-for-preservation
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