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Re: Acid Free



On Fri, 22 Aug 1997, Jason Thompson wrote:

> Hello,=20
>
> We're looking to educate ourselves more on the issue of what the term "Acid=
>  Free Paper" translates to in real world use books.=20

Truly, "acid-free" is a buzzword, and papers can be acid free, but still
have a high enough groundwood content to become acidic over time.
"Permanent paper" is a more descriptive term.

The best place to find information about permanent papers is Abbey
Publications in Austin, Texas. Ellen McCrady publishes both the Abbey
Newsletter and the Alkaline Paper Advocate. In addition, she published a
book titled "North American Permanent Papers" in 1994. The book lists
permanent papers (which meet the ANSI/NISO standard, cf below) by type,
manufacturer, and name, produced in North America.

The permanent papers book has a section on standards and testing, and to
make a long story short, the American National Standards Institute
(ANSI), and the National Information Standards
Organization (NISO), have developed a standard which calls for a pH of
7.5-10 for uncoated paper and 7.0-10 for coated paper core, provided the
paper as a whole meets the alkaline reserve requirements; a 2% minimum
alkaline reserve; tear resistance as measured by tear index: 5.25
mNm-squared / g for uncoated papers and 3.50 mNm-squared / g for coated
papers; and maximum lignin content 1%. (lignin being the stuff in groundwood
which creates acid in paper).

(This information is taken directly from McCrady's book, page 35.)

The ANSI/NISO standard, Z39.48-1992,
describes "permanent" as paper able to last several hundred years under
normal storage conditions in libraries and archives. McCrady, in the
October 1989 issue of the Alkaline Paper Advocate, published "six
definitions of permanence, six of durability, and three of the
relationship between them"!!!! (McCrady, p 23)

A link to Abbey Publications is available in CoOL, which is also where
this list is archived. (http://palimpsest.stanford.edu)

If what you are looking for is a way to assure your customers their
photos are safe, "acid-free" or "archival" makes a much better marketing
concept. (I would be inclined to think the buffered papers would be
better because of the kinds of things people put into albums, such as
newspaper clippings, old ticket-stubs, and so on. These materials are
HIGHLY acidic, and the acid certainly migrates. If you have ever stuck a
newspaper clipping into a book you have seen the effects of this--the
area in contact with the clipping has developed a yellowish-brown stain
the exact size and shape of the clipping. That is acid migration. The
buffering provides a sort of barrier against acid migration.)

That's all I can manage on a Friday afternoon, but I strongly recommend
the Abbey publications!!!
Clara Keyes


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