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[BKARTS] Deacidification, etc.



This is a complex question, requiring more than one answer.

Deacidification is a fairly common adjunct to acqueous treatment
of paper.  Buffering is not always part of such treatment.

The measure of acid/base is a log scale measurement of ions, 7 pH being
neutral. (Don't ask me what this means; look it up and learn.)

So.  Paper treated to make it pH neutral works best within the first
seven years.

Gelatine, a product of animal skin, etc. has a pH of approx. 5.5, and
is very stable at that pH.

Linen and hemp fibers have a pH of 6, or thereabouts.  Wood pulp paper
has a pH somewhat higher (or lower), in general.  Depending on the
chemistry used to reduce the fiber to a state suitable for the manufacture
of paper.

There are no simple/easy treatments.

Jack

>While not directly faulting Ms. Lightcap, I am curious if the procedure
>of deacidifying text (paper) as old as 1572 is a common practice amongst
>bookbinders/restorers.  The first and most obvious question would be to
>ask, why was it felt that paper that old needed to be buffered against
>acidic development/degradation, when it presumably has 'lived' just fine
>for over 400 years.  There has been quite a lot of research about acids
>in paper, and different rates of oxidation of different types of
>furnish.  Linen, the common paper fiber used in Europe in the 16th
>century, ages quite well.  Also, gelatine used as a size at that time
>has also been observed to aid in paper permanence.  There is some reason
>to believe that in washing papers of this age, we may be washing out
>some of the gelatin, leaving the paper more open to future attack.
>
>Generally, the process of deacidification (or alkalization) is used to
>slow down the rate of oxidation in the future. One cannot reverse time
>with this process.  Deacidification is generally reserved for papers of
>the 19th and 20th centuries, which for various reasons contain many
>constituents that lead to brittleness and oxidation.
>
>Doug Sanders
>
>> -----Original Message-----
>> From: Susan Lightcap [mailto:slightcap@xxxxxxxxxxxxxx]
>> Sent: Tuesday, January 21, 2003 10:50 PM
>> To: BOOK_ARTS-L@xxxxxxxxxxxxxxxx
>> Subject: Re: odd things that one finds in a book
>>
>> When I was deacidifying text from a 1572 French medical book bound in
>> limp vellum in Basil, Switzerland (snip)

Thompson Conservation Lab.
7549 N. Fenwick
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USA

503/735-3942  (ph/fax)

http://home.teleport.com/~tcl

"The lyfe so short; the craft so long to lerne."
Chaucer  _Parlement of Foules_ 1386

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