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Paper deacidification



I am reprinting information on the deacidification and washing of paper
sent to me offline by Rodney Fry of Berkshire in the UK:


Dear Betty,

I have just read your message in my Book_List Digest.  You ask for
comments off list.

I have washed and deacidified quite a number of books at home  prior
to my rebinding of them - it is hobby not a job by the way!

I use Analar quality reagents and in this case saturated calcium
hydroxide solution which I make up with the powder purchased from a
chemical company.  The pages are washed first in tap water which in
my area is high in calcium ion concentration, i.e. hard water.  This
is all described for example in "The Paper Conservator", "The Washing
and Aqueous Deacidification of Paper",Hey, M, Vol 4, 1979.  I have
carried this out on newspaper articles, 1611 & 1800 Bibles ( I don't
think I would want  to do another one there are so many pages!!) and
Tournefort's Herbal, 1719 for example.  The washing must be done
prior to deacidfying (see "Paper Washing", Lienardy,A & van Damme,P,
Vol 14, 1990). Ideally the paper should be pre-wetted in a water/iso-
propanol solution - roughly 20-30% alcohol.  This alcohol mixture
becomes discoloured but it can be used many times as the coloured
constituents are removed in the washing - the alcohol may need
topping up as it evaporates.

A more recent article ["The Use of Chelating Agents in Conservation
Treatments", Burgess,H, Vol 15, 1991] describes removing iron
compounds which includes rust.  This is probably more difficult it
requires a solution of sodium dithionite plus ethylenediaminetetra-
acetic acid.  The article mentions use of oxalic or acetic acid,
e.g.lemon juice, but the author cautions that this may disintegrate
the paper.  Perhaps this doesn't matter too much on the spine if you
intend to guard the fold?

Really the amount of effort depends on the value of your newsletters.
 Perhaps the simplest is to wash and deacidify only as the rust
stains are only visible on the fold and are not in the text block?

Hopes this helps.  You might try trawling through the Book_List
archives also.

Regards
Rodney Fry

And:

Dear Betty

Thank you for your reply.   I have no objection to you using my
comments - the information has come from those authors more
knowledgeable than me in the area of conserving books.

As you suggest 2000+ pages does seem a lot!!  However on reflection I
suppose I must have done something of that order, two Bibles are some
800 leaves or so,  plus the herbal which was about 300 leaves, plus
some other books all over quite a few years.

The washing takes about 15 min changing the water a number of times.
The  deacidifying about the same.   It will tend to wash out the size
and you may find it better to resize after the processing.

It is sensible to check on a page that the ink is not affected by the
washing and that the paper does not disintegrate - one book of 1698
had poor quality paper which did not take to washing too well.

On the subject of effort the herbal took about 100 hours of my spare
time using the bathroom - so I was not too popular with my wife!
However it really depends what sort of space you have to lay-out the
leaves to dry prior to pressing.  A lot of the leaves required
guarding repairs on the spine and also the leaves were lightly
bleached as well as deacidifying, which also doubled the time I
suppose.  They needed to be washed in water and dilute acetic acid,
then deacidified again. The leaves were supported on inert mesh
material 3 or 4 leaves on top of one another and gently manipulated
every so often - photographic developing dishes are quite useful or
plastic trays from garden centres.  At the finish the leaves were
initially placed on clean newsprint to absorb excess water, then kept
in a pile as I worked through them to repair the spine folds.  They
were then laid out to dry and when virtually dry were placed between
clean blotting paper sheets under a light weight for final drying.

The chemical powder should be sufficiently pure to avoid adding
contaminants to the paper.   As I said mine are high quality
reagents, i.e. the impurities which could deposit on the cellulose
are measured in parts per million.  I'm not up to date with the
latest in chemical terms, but broadly speaking there are general
purpose reagents which are the cheapest, high quality reagents and
spectroscopically pure reagents.  Fortunately calcium hydroxide is
not a particularly expensive chemical and it needs only a couple of
teaspoonfuls in a litre of water and left overnight to settle.  This
will last quite some time refilling the bottle each time and keeping
it stoppered.

Probably there are other list readers who will do things differently
or have the facilities of a laboratory.

You say your tap water is acidic? (The PH is about 5. Betty) Will your
local water company supply a chemical analysis as here in the UK to the
user?  The water in my area has 140 parts per million Ca ion concentration
and faint traces of many other things.

Hope that provides a little more background.

Regards
Rodney Fry
Crowthorne,
Berks
UK



Betty Storz   storz@mcn.org
Mendocino, CA

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