Humidification

Diane Banning of the King County Archives asked about
humidification.

My department started a project a few months ago which involves
humidifying and flattening thousands of maps. We converted a small
room, formerly a vault, into a humidification room.  The room is
plastered and painted.  After placing the items on a series of
bakery racks, we turn on 2 electronic humidifiers and shut the
doors.  As materials loosen up, we unroll them to expose other
areas.  Some items are ready at the end of the day, some require
more humidity.  We do not run the humidifiers at night. We generally
humidify Monday through part of Thursday, then air out the room over
the weekend, using an industrial fan to increase circulation and dry
out the plaster. To prevent/kill fungi, we used to clean the room
weekly with bleach water, but found that regimen to be unnecessary.
We normally clean it every other week, normally on Thursday
afternoon, so the room can dry out over the weekend.

Although this method is much faster than a passive system, you do
have to keep closer watch on things.  The heavy sizing on drafting
linen, for instance, can absorb too much water rather quickly,
leaving you with a very limp cloth that will then stick to blotting
paper.

Michael McColgin, Preservation Officer
Arizona State Archives
1700 West Washington
Phoenix, AZ  85007
602-542-4159
Fax: 602-542-4402

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                  Conservation DistList Instance 9:69
                   Distributed: Friday, April 5, 1996
                        Message Id: cdl-9-69-003
                                  ***