I am interested in knowing the acidity of common wallpaper, 
and also, specifically, of the plain (undecorated) surface 
when watercolor or gouache paint is applied,
and if there is a product that can be applied to the surface 
to lower its acidity without damaging the paper or reducing its durability.

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Clarification of Question by veronika-ga on 24 Jan 2003 08:32 PST

am interested in using wallpaper for another purpose -- to paint on
the blank surface...as question indicates.   So if the acid content of
the paper is high, I would like to know what antacid substances are
available and where.  Thanks.

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Clarification of Question by veronika-ga on 24 Jan 2003 09:04 PST

I found some substances for deacidification of paper, but the method
is not permanent.  I'm interested in knowing if there is a substance
that works permanently, is relatively easy to apply, and is reasonably
priced.

Hello and thank you for your interesting question.

The substance you are looking for is a deacidification agent, which
will raise the pH of the wallpaper either by alkalisation (that is, by
applying a high-pH compound to the acid surface) or by buffering (that
is, by applying a buffering chemical that will release OH- ions to
pair with and neutralize the acid components of the paper.

The Talas Company sells several formulations of Bookkeepers
Deacidification Spray, in which a buffering agent, magnesium oxide, is
delivered by aerosol or by brush. Formulations #4 and #12 are said to
be specially suited for penetrating thicker boards and papers.
They also offer an isopropoxy magnesium isopropyl carbonate
deacidification agent. "This formulation will have the advantages of
improved stability, ... improved ability to penetrate and deacidify
thick paper and paperboard, and much lower potential to affect
sensitive inks."
http://nt.bnt.com/talas/menu.html?category=124

This approach is specifically referenced as as an appropriate, but
expensive, approach to using wallpaper samples as 'scrapbooking'
material, although the results will not necessarily be permanent if
the paper is too high in lignin:
"Most wallpaper is acidic and some contains vinyl. There are many
scrapbookers on the Internet who are well-intentioned and have posted
information about using wallpaper to save money but there is no way
for you to know if it is safe. Even if you use a pH pen to check the
acidity most wallpaper probably contains lignin which in time will
breakdown and BECOME acidic. If you REALLY want to use wallpaper, you
could spray it with Archival Mist but at $50 per bottle that makes
your wallpaper an expensive addition to your scrapbookers AND the
wallpaper may still turn brown even after being sprayed with Archival
Mist."
http://scrapbooking.com/mag/information_and_answers.htm

If you find the pricing of the Talas company products prohibitive, the
alkalisation appoach has been used successfully, and most likely at
lower cost. The restoration of antique and highly acid wallpaper was
achieved by a two-step process:
"The sheets of wallpaper were placed on damp capillary matting and
sprayed repeatedly with a very dilute CMC (sodium carboxymethyl
cellulose) solution. This not only further consolidated the paint
layer but drew out much of the acidic pollution. The wallpaper was
lined with a medium-weight oriental tissue, using a wheat starch
paste. Tear repairs and patches were incorporated during this process.
Alkalisation was carried out during lining using calcium hydroxide
solution."
http://www.ihbc.org.uk/context_archive/74/wallpaper/wallpaper.html

Have you considered obtaining lignin-free and/or acid-free wallpaper
to begin with? Here are some sources to consider, if the sizes they
offer are sufficient for your use:

The Library Binding. Service, P0 Box 1413, Des Moines IA 50305
(800/247-5323 except in Iowa furnishes acid-free, lignin-free board
with a pH of 8.3 and calcium carbonate content of 3-4%. The board
comes in different sizes and is .055" thick.
http://palimpsest.stanford.edu/byorg/abbey/an/an08/an08-1a/an08-a110.html

"12x12 minigraphics papers"
http://membks.bravepages.com/HTMLpages/MGpaperlist.html


Search terms used:
wallpaper acidic
"deacidification agent" application  paper
wallpaper acidic conservation
wallpaper "lignin-free"

Thank you again for giving me the opportunity to answer your question.
 If any of the above is unclear or insufficient for your needs, I
would appreciate it if you would hold off on rating my answer until I
have an opportunity to provide further clarification.

Sincerely,
Google Researcher Richard-ga

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Request for Answer Clarification by veronika-ga on 26 Jan 2003 12:04 PST

thanks for your thorough work...but could you clarify a few things? 
first, are you saying that all treatment processes are impermanent? 
and second -- the source you mentioned for acid free paper seems to
apply to "boards."  If you could find a source or sources for acid
free wallpaper -- it is lots of length to the roll, canvas-like
qualities, and relative inexpensiveness that I am looking for -- you
would rate a mega honors.

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Clarification of Answer by richard-ga on 27 Jan 2003 07:54 PST

Hello again.

The reason that the anti-acid treatments don't guarantee permanent
results is that they cannot remove all of the lignin from the product,
and over time the lignin will generate new acidity (lignin reacts with
light, which is why papers are best stored in the dark).

I mentioned the acid-free board in my answer because I thought it
might give you the size you needed.

I've looked further in response to your request for clarification, and
although I didn't find a wallpaper product that's lignin free, I did
find a 28 inch x 5 foot roll of lignin-free paper.
Island Blue
http://shopping.islandblue.com/catalog.cfm?mcata_id=3&scata_id=18&product_id=1212

If this is a sufficient length (and if you can live with the price)
I'd suggest you consider using it.  If there's no lignin or other
acid-maker in the product to begin with, it should stay acid-free
forever.

Search term used:
 wallpaper "lignin free" -paste

Regards,
richard-ga

There's a chemical that conservators and preservation experts used to
deacidify acid paper.  But am not sure you want to spend that kind of
money to protect simple wall papers (i.e. might be cheaper to replace
them). Also it does not work on all instances as sometimes the ink
used on the papers are susceptible to the basic solution used for
neutralization.