Great article, although it doesn't really provide us with a
truly satisfactory solution (...get it? "solution"...?)
But I'm surprised this article doesn't mention the foolproof,
non-water-damage method: Nuclear Irradiation! Sure... why not? Slip
that foxy poster into one of those machines they use to kill cancer
tumors with and I bet those spots would disappear plenty quick! Of
course, Sue would have do develop some new, lead-shielded frames for
displaying these de-foxed mutants, but anything is better than those
pesky little brown spots...
On a serious note, what about the de-acidification solution used
prior to linenbacking? If a restorer used the Chlor-T first to remove
the foxing, rinsed it good, then put the poster through the
de-acidification bath, wouldn't that tend to neutralize any remaining
Chlor-T residue?
Sent:
Thursday, September 15, 2005 10:48
Subject:
[MOPO] Foxing
here's some good reading,
Foxing can be masked with laundry bleach which might look
okay the first couple years, but Chlorox does immediate damage to the
cellulose content of paper, & the residue salts cause increasing
damage in the long run. There are additional chemical means of
neutralizing the residue salts, but those additional chemicals also
have long-term effects.
Foxing can also be masked temporarily with peroxide, but
peroxide damages paper even more quickly than Chlorox. Both methods are
essentially those of the ignorant or the crooked.
Unfortunately foxing is most frequently caused by a living
organism which may or may not continue to grow. In ideal conditions of
temperature & humidity for the book, this fungus either ceases to
grow or develops at a such a low rate that the chemical solution
residues are the more harmful in that chemical residues will hasten
rather than retard the natural break-down of paper but the arrested
fungus may remain only a minor speckling of discoloration.
Some tests on foxing detect no fungus present, so some
archivists posit the possibility of multiple causes, leaving an element
of "mystery" about the cause & nature of foxing. One thing is
fairly standard: foxing occurs best in papers that contain iron
impurities or high acidity. Iron is usually introduced into paper
during manufacture, from water containing iron, from old papers
manufactured with aid of iron machinery & iron beaters. Foxing
caused exclusively by iron, & not by fungus, archivists distinguish
as "dendritic growth stain" & at its ugliest it is a big fan-shaped
discoloration that apparently follows some metalic molecular pattern.
Fungal foxing usually requires paper acidity, acidity being the result
of bonding agents used from the 1890s through 1980s on cheaper papers,
though it's possible the acidity of some foxed books is a byproduct of
the fungus itself. Both forms of foxing are treated the same way, by
washing the paper in an oxidizing agents, which requires submersal in
dilute chemical then rinsing.
Talus, a company in New York, sells powdered Chloramine-T
specifically for use in removing foxing from archival materials,
including books. Unfortunately it requires the powder to be dissolved
in water & the foxed item to be immersed in the water, then
submersed a second time to rinse out the Chlor-T residues. So it treats
one signature-leaf at a time, the book having first to be disbound.
State of the art archival preservationists have found that
even the Chloramine-T leaves a residue after rinsing, & is harmful
over time, but no better option has been proposed. It is restricted to
use on items truly worthy of preservation, & which have egregious
foxing. All de-foxing chemical bleaches have to be rinsed. A book of
considerable age & rarity that is being devoured by fungus, it can
be disbound, each separated signature soaked in dilute Chloramine-T,
then rinsed to remove residues, & rebound. This is not very useful
for entire books of only average value.
There is a very dangerous & impossible to do at home
method of removing foxing from books that used Chloramine gas. I've
seen reports that this is safe for the book & may be the only
method guaranteed not to replace foxing with waterdamage. But the
technique requires resources only the aerospace industry could provide.
The book has to be placed in a riffled-open position so all the pages
can be gassed, & the gas chamber better be air tight. I've never
known of this being done by booksellers, & no standard archival
resource mentions it as a viable option, though the Univeristy of
Washington experimented with it to good results with the assistance of
Boeing Aerospace back in the late 1970s -- I've heard nothing about it
since.
Some archivists claim (hope rather) calcium hypochlorite
leaves less residue even than Chloramine-T soaks, but others have said
calcium hypochlorite clings so well to paper it is extremely hard to
rinse out & so is not preferable to Chlor-T. Again, it's a
submersal technique, hardly practical for books.
One old method is a three-part deal, requiring three
photographic chemical trays. The first tray has potassium permaganate
diluted one to 16 parts water. Each page is submersed for a half-minute
this solution, then moved to a second tray with sodium meta-bisulphite
diluted one to sixteen parts water, again for a half-minute. The third
tray should be a "flushing" tray with water running thrugh it
continuously. This a rinse, to wash out the killed & loosened
foxing, & to remove the chemicals themselves. This elaborate method
has pretty much been displaced by Chloramine-T or by calcium
hyupchlorite which requires only one rather than two distinct baths
before rinse.
Sodium borohydride in a 5% solution is also used. The
majority of archivists don't seem to use it, but a few claim it does
not need to be rinsed, because its residues leave a deposit of
alkalinity that might actually benefit the paper.
Exposure one sheet at a time to UV light (artificially
generated, or mere sunlight exposure) is the only "safe" bleaching
method & even that is not safe for paper containing lignen, which
will rapidly oxidize from ultra violet exposure, with darkening effect
as lousy as the foxing. It works best with slight moistening of the
surface & strong UV radiation. If it's just the random page it
might be a tolerable method, otherwise it takes one hell of a long
time. The moisture-&-UV method is reportedly the least damaging of
all methods (except possibly the unavailable gas-chamber method). The
Paper Conservator #21, 1997, has a lengthy article on the method:
"Aqueous light bleaching of modern rag paper: an effective tool for
stain removal." It is useful for cleaning foxed color plates that have
been removed, treated, & reinserted, but doing it to an entire book
would not be time effective.
All methods requiring water (dampening, or submersive) risk
damage towater soluable inks. Most dyes used in books are color-fast
but very old books with color plates sometimes used indigo in the
inking mix to achieve purple & blue colorations that will bleed
when dampened. Further, rinsing with fresh water (from the tap) risks
introducing iron impurities to the paper, damaging over time, so
dionized or distilled water is sometimes recommended. High quality
papers can sometimes be wetted in a manner that will dry unharmed, but
an awful lot of papers will either change their thickness or wrinkle
before they dry, & that damage is irreversible. Spot-testing helps
in the decision process. By & large it is a trade-off &
defoxing is recommended only when the level of foxing is more
detrimental.
But I'm afraid any bookseller who claims to have a magic
method of foxing removal is likely spraying a mist of dilute Chlorox
that damages the cellulose in the paper & does permanent harm,
though if he can sell the cleaned-up book quickly enough by making it
look momentarily nice & bright, he's probably succeeded at his only
real goal. All functional methods apart from UV exposure require
submersal so one would expect signs of a book having been disbound
& rebound, with some slight evidence of contact with water if not
outright overt water damage.
The bottom line is there is no truly reasonable &
effective way of defoxing a book, perhaps at most these methods are
credible for a single fox-stained illustration plate or a few
gregiously fungally-darkened pages that'll look better slightly
wrinkled than they look all splotchy.
Books stored in temperature controlled rooms (in the 60-67
degrees F range) with no more than 50% humidity will not develop
foxing, & foxing that is established will be retarded in further
growth. If you live in the Philipines or South Carolina or Dallas where
humidity can be 100% then books that have foxing started in them are
pretty much doomed & will infect nearby books as well, unless a
first-rate dehumidifier is in place.
Visit the MoPo Mailing List Web Site at www.filmfan.com
___________________________________________________________________
How to UNSUBSCRIBE from the MoPo Mailing List
Send a message addressed to: [EMAIL PROTECTED]
In the BODY of your message type: SIGNOFF MOPO-L
The author of this message is solely responsible for its
content.
