Digital BW, The Print

From: "Paul Roark" <paul.roark@...>
To: "DigitalB&WPrint" <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Monday, September 23, 2002 8:35 AM
Subject: [Digital BW] Deacidification -- It's not just for EAM


> There is an excellent and reasonable current summary of information
related
> to paper preservation at:
>
> http://www.clir.org/pubs/reports/pub95/contents.html
>
> The article is called, "Preservation Science Survey --
> An Overview of Recent Developments in Research on the Conservation of
> Selected Analog Library and Archival Materials" written is December 2000
and
> published in cooperation with the European Commission on Preservation and
> Access.  Chapter 2 is devoted to paper.
>
> One interesting note seems to say that even "acid free" paper will not
stay
> that way long. The article notes, in part:
>
> "Formation of acids"
>
> "While it is well known that papers become more acid with age, it is
> generally assumed that this declining pH does not significantly contribute
> to the degradation of paper. It is often presumed that only the acids
> introduced in the manufacture of paper and those absorbed from the
> environment are responsible for the deterioration of paper. In this
context,
> the term "acid-free," which in effect equates neutral and alkaline papers,
> is often used to imply permanence. However, the spontaneous formation of
> acids in cellulose during aging cannot be overlooked as a cause of paper
> degradation."

Paul,

A good link to have. As you may have noticed they have not mentioned lignon
anywhere. It is the lignin in cellulose derived papers that decomposes to
produce weak acids. That is why it is important that un-buffer papers be
both acid free and lignin free with as little sulpher content as possible.
For more in depth information check out the Stanford site:

http://palimpsest.stanford.edu/
http://palimpsest.stanford.edu/byauth/misc/dirsci.html#lc
>
> ...
>
> "[N]eutral papers cannot remain acid-free for long. Weak acids formed in
the
> degradation of cellulose and hemicelluloses have generally been considered
> not to pose as significant a threat as do stronger acids introduced from
> acidic alum-rosin size or those formed by absorption of oxides of nitrogen
> and sulfur from the environment. However, the present findings suggest
that
> these weak acids accumulate at a sufficiently high rate to contribute
> significantly to the increasing acidity in paper as it ages. Alkaline
papers
> showed appreciably higher [Is this a typo?-PR] rates of accumulation than
> did other papers, since the acids formed are immediately neutralized and
> cannot enter into other reactions or dissipate.

Sort of. Chemical weak reactions such as this are often bidirectional and if
the reaction products are being removed then the reaction will continue
rather than stabilizing. It might be more appropriate to substitute
"generation" or "formation" for "accumulation". Since the acids are removed
they cannot harm the paper.

> It was also shown that these
> weak acids attach themselves strongly enough to paper, probably by
hydrogen
> bonding, that they are not easily dislodged from the paper matrix, even
upon
> airing. Because of this tenacity and because they catalyze their own
> formation, these acids present a constantly escalating source of damage
that
> can be dealt with only through deacidification."

Good un-buffered papers need to be made from quality alpha cellulose, and be
both acid-free and lignin-free. Paper permanence is not image permanence.
You have often seen in your fade tests that EAM did better than other
papers. Most recently on the PiezoTone tests compared to Photo Rag which is
alkaline buffered. While alkaline buffering is good for paper life, we don't
know if it is good for ink life.

Martin Wesley

http://www.borderless-photos.de/guests.html

From: "Paul Roark" <paul.roark@...>
To: "DigitalB&WPrint" <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Monday, September 23, 2002 5:08 PM
Subject: [Digital BW] Deacidification -- It's not just for EAM


> Martin,
>
> >> ... "Preservation Science Survey --
> > >... the spontaneous formation of
> > >acids in cellulose during aging cannot be overlooked as a cause of
paper
> > >degradation."
>
> > As you may have noticed they have not mentioned lignin
> >anywhere. It is the lignin in cellulose derived papers that decomposes to
> >produce weak acids.
>
> Clearly lignin is a problem.  However, to a lesser degree, it appears
that,
> except in a vacuum or encapsulated with argon gas, cellulose itself is
> attacked by oxygen and other airborne substances.  Among the byproducts of
> these attacks are acids that then launch their own attacks.  These
reactions
> appear to cascade at accelerating rates.

Paul,

I think that there is not even consistent agreement among the
conservationists on the matter. I have read articles that say that some
lignin is desirable or necessary for mechanical strength and stability. Some
feel that acid-free, lignin-free alpha cellulose is superior to rag papers.
All of these modern papers are far above the quality of papers which created
the paper disaster that ran from roughly 1850 to 1950. Even photographs from
that period are still with us. I have century old photographs in antique
albums that are holding their own.
>
> > ...
>
> > often seen in your fade tests that EAM did better than other
> >papers. Most recently on the PiezoTone tests compared to Photo
> >Rag which is alkaline buffered. While alkaline buffering is good
> >for paper life, we don't know if it is good for ink life.
>
> There are quite a few articles that indicate strongly that buffering
> accelerates the oxidation of pigments.

This is a good indication of how "archival madness" is pushing things around
without any good thought. Buffered papers have been known to be the
preferred choice for books for decades, probably half a century. So buffered
papers become the standard for "archival" use. Paper companies then use
buffering in fine art papers for inkjet use without any real assessment
being done if this is the proper choice or not.
>
> One of the fascinating possibilities coming out of the mass
deacidification
> experience is that the clay coatings on papers can act as barriers to the
> buffering molecules.  While the acids (positive hydrogen ions) migrate to
> the buffers, the buffers/bases do not appear to migrate.  So, the inkjet
> coatings might actually protect the pigments from buffering that is on the
> back paper only.  Of course, if the manufacturer did this, they'd probably
> have to put interleaving between each sheet, because there buffering
agents
> are generally particles and rub off as a residue to a certain degree.
Thus,
> the back of a buffered paper would "pollute" the front of the next piece
of
> inkjet paper.

Both sides and the middle of all the buffered papers I have checked with the
pH pens test out basic.
>
> I received a very nice response from the founder & principal of Wei T'o.
To
> his credit, he honestly said that his deacidification product would
probably
> not be a good one to use.  Consistent with my research, the magnesium
> compound they use is too basic and would probably affect the pigments.
(The
> existing sprays, including the one sold by Light Impressions, do not
appear
> to be the answer.)

I am not surprised and it is nice to see someone being so honest about their
product.
>
> It appears calcium carbonate is a more appropriate buffer, if it can be
kept
> from the surface.  It's probably easy enough to work with in an aqueous
> solution that I might just give it a try to see what happens.
>
> Along those lines, I have now been led to a researcher who is having
success
> with a deacidification substance that is a dry powder.  This might be
ideal,
> since it would almost certainly not penetrate the coating and ever touch
the
> surface and pigments.

I would strongly discourage you from doing anything to the prints you have
made. The odds of you doing more harm than good seem very high to me. An I
frankly see no reason.
>
> In the meantime, I just took delivery of some Eclipse Satine.  I think I
> might prefer it to Legion Photo Matte due to the LPM over-OB'd coating.
>
> By the way, with LPM (and I'm guessing with Eclipse Satine, both of which
> appear to have [second-rate] coatings that can't take the ink load of EAM)
> I've found using the Epson driver setting of "Photo Quality Ink Jet" paper
> holds back the ink enough to avoid the slick, uneven look on the 100%
patch.
> LPM actually delivers a higher Dmax with less ink.

Eclipse has a weak Dmax with all the inks and I don't think that will change
unless they change the coating which they have done at least once. The
original batches I got had even worse Dmax and mottled. It is a wonderful
paper for its incredible bright and neutral base. It is the most revealing
of ink color of any paper I have tried. Nice texture as well. I personally
do not like LPM because the OBA's give it a bluish look. I would ecpect it
to suffer badly as the OBA's turn yellow. Worse than EAM.

Stick with EAM if that is what you like. I have not seen any data to suggest
that it offers less image permanence than any other paper. In fact your own
data suggests that it may be superior. What data do you have that says your
prints will last longer on LPM or Eclipse? Or which paper will outlast the
others?

For myself I really like the Photo Rag and the German Etching and plan to
use them. If it turns out that they are not the last word in "archival," I
don't care. As more information and newer products come along, then we can
make more intelligent decisions. The bottom line is that is paper
impermanent and is not going to last forever no matter what we do. Right now
it is nothing more than a guessing game, so why not "guess" on the paper you
find most appealing?

Martin