dessicants, photos, and baggies
>From: Michael McColgin <mimccol@...>
>Subject: It is a bad idea
>Content-Type: text/plain; charset="us-ascii"; format=flowed
>I cannot post to this list, so here you go.
>> >DESICCANT PACKAGES TO SOAK UP MOLD SPORES
>> >Here's my genealogy quick tip:
>> >I inherited a treasured box of one-hundred-year old photos.
>> >Unfortunately, they had been stored badly. Rodents had gotten to
>> >them, as well as mold and mildew. I coughed and wheezed whenever I
>> >opened the box to copy these lovely old photographs. I put them
>> >together in bundles according to families, in zip lock plastic bags.
>A few points to consider:
>1. Dessicant packages do not soak up anything except water. Dessicants can
>reduce the RH in an closed environment.
>2. Fungi are rather fussy about their environment. They like a high
>humidity, little if any airflow, little if any light, and to be left
>alone. By reducing the RH in the bag, the dessicant basically causes the
>fungi to go dormant. The fungi will become active again as soon as
>conditions are right.
>3. Zipper-type bags create a stagnant environment which is almost airproof.
>Deterioration byproducts, and there are many, cannot escape, so the
>contents basically stew in their own juices. Items which were originally
>in better shape will soon become "contaminated" and deteriorate faster than
>they would normally.
>4. Light Impressions has a great variety of housings for photos and negs.
>Avoid all types of "plastic" enclosures for this collection. Use paper
>enclosures. If you must use a plastic of some sort, at least enclose
>a piece of MicroChamber paper from Conservation Resources, International.
>This paper absorbs deterioration products, so materials do not stew in
>their own juices.
>Arizona History and Archives Division