Digital BW, The Print

Thad Munnerlyn [thm@...] wrote, in part:

>Light Impressions carries a product ... in their conservation section.

Great, I'm a big fan of Light Impressions.  It's probably made by one of the
leaders in the industry.

>is the back of the paper a different Ph from the coating?

Probably.  It appears one of the challenges is that buffering damages
pigments.  So, neutralizing and buffering the paper must be done in such a
way that the buffering does not reach the coating.  Wei T'o makes different
solutions that penetrate differing amounts.  Choosing the right one and
finding an accurate, repeatable application method are probably critical
pieces of the puzzle.  Hopefully Wei T'o will see the potential of a market
and customer base (maybe even Epson) large enough to get involved directly.
I've e-mailed them.

The problem with the sprays appears to include evenness and accurate
metering of the amount of buffering.  I think a thin transfer sheet that is
immersed, saturated and then used to transfer a repeatable amount of the
solution to the paper might be integrated into my current procedure of
dampening the back of the paper to take the curl out of the 24" rolls I use.

The extent of migration of both the acid and buffering are related issues.
The acid may be no more than a loose proton (hydrogen ion).  It's so small
it can easily migrate through paper.  We know that an acidic cardboard will
attack an adjacent acid-free print.  The good news here is that we can mop
up a lot of this stuff with less than 100% penetration.  Hopefully the
buffering will not migrate so far as to attach the coating if it is held far
enough away.

I'll test the extent to which the deacidifiers attack the pigments.

Ernst Dinkla [E.Dinkla@...] wrote, in part:

>...There's an expensive technic with a kind of gas chamber etc
>where books in batches are deacified. ...

Yes, the big money has gone into "mass deacidification."  It's a huge
field/knowledge base that we can tap into.

Thomas Keesling [tom.keesling@...] wrote, in part:

>What does the Library of Congress do, if anything, re deacidifying paper?

I don't know.  However, it appears everyone is looking at this approach.
Frankly, it's an obvious approach.  I was about to put a calcium carbonate
buffer into my print-flattening distilled water sprayer to see what would
happen when I decided to do a "quickie" internet search to see if anyone
else had thought of this.  Boy, had they ever.  It's huge.  And the rewards
could be huge.  People are talking hundreds of years of life added to cheap
papers.

Note, EAM/EEM is "cheap paper" but it is also the only one that delivers the
image quality I'm looking for.  I love cotton for clothes, but its softness
results in "fluffy" papers that generally don't give me what I'm looking for
in a paper.  This is a stylistic and subjective view that just reflects my
personal preferences.  I can fully understand how others might prefer the
cotton.  For my tastes, PhotoRag may be the best cotton alternative (about
the only acceptable cotton paper I've ever seen), and I am not ignoring it.
However, for me, EAM/EEM still wins by a very large margin.

Nonetheless, my roadmap includes a diverse approach to this problem that
will give me/us the best shot at a solution.  The UltraChrome-compatible
inkset transition is part of that.  The RC papers may be the best answer.
Just seal a buffered paper in a sandwich and coat over it.  This give a
better Dmax and the particles are pre-coated for durability. I'd sure like
to be compatible with this possibly-superior approach.

The coating of our uncoated particles is also related.  The best coated
image I've yet seen was a coated EAM done by Nghi Nguyen.  We are looking at
several application methods.  Immersion may be the easiest.  It coats both
sides, thus encapsulating the entire package.  This might be good or bad.
The Mayer rods that Robert prefers may be the best way to coat only one
side.  However, the airbrushed test print from Nghi is very nice.

I like the immersion method because it might be done with virtually no
preparation or cleanup.  Nghi's initial trials appear to produce superior
results.  Robin Whetton, the proprietor of the European MIS distributor has
in his darkroom company vertical developing trays the might seal well enough
to just open the top, dip, close the top.  All done.  I think I may have
another sealable tray method that is even cheaper and easier.  Robin is
sending us some vertical trays for testing.

Whether to coat one or both sides is also an issue.  If totally
encapsulated, the oxidation may be reduced more.  Also, the print may be
more curl-free, since the coatings offset each other.  Additionally, lignin
(the hard glue that allows trees to get so tall but wrecks old paper) does
not, it appears, initially cause trouble.  It may become a problem only when
airborne substances interact with it.  So encapsulation may help prevent
lignin from doing damage.  On the other hand, since deacidification is a
science that will probably advance substantially, and since some of the
acids are such that they act like gases that migrate -- including out of the
paper to , possibly, an adjacent interleaving that grabs the acid, sealing
the back of the print may be a mistake in the long run.

I don't have good answers yet, and there may not be any for years.  Who
knows, maybe I'll make two copies of my display prints that I offer for sale
and just mount the second version of the print behind the first so that
buyers will be able to do whatever works best, including just trashing one
and displaying the other (possibly second rate but "acid free") image when
the first one self-destructs.

This is going to be a long and complex story, but I think what I've learned
is that acidic paper is not the end of the story at all.

Paul
http://www.PaulRoark.com
_________________________


--- In DigitalBlackandWhiteThePrint@y..., "Paul Roark"
<paul.roark@v...> wrote:
> Does anyone have any experience with or knowledge relating to the
issue of
> deacidifying paper?
>
> There appears to be a large body of information relating to mass
> deacidifying the huge body of old documents that are now self-
destructing
> due to the acid content of the paper used.  A related issue is
deacidifying
> individual papers, posters, etc.  The goal, of course, is to extend
the life
> of these papers.  Numbers like 300 - 500 years are tossed around.
It
> appears to be a big deal with some lofty claims.
>
> The process is to impregnate an acidic paper with acid-neutralizing
> chemicals and buffering.
>
> Two companies have sprays that are said to be ideal for individual
posters,
> etc.  These two products are called "Wei T'o" (the name of a
Chinese god who
> protects books) and Bookkeeper.  The Wei T'o website has substantial
> information on it.  See http://weito.com/intro.htm
>
> A several year old test on a Stanford cite draws into question the
> effectiveness of the Bookkeeper spray product, while indirectly
indicating
> to me that the overall approach does have merit.
>
> The obvious concept:  why not just spray the back of EAM with a Wei
T'o
> spray to deacidify the paper while not touching the surface (where
buffering
> might reduce the light fastness of the pigments).
>
> If we can't find a better-looking paper, maybe we can make the
paper better.

>
> Paul
> http://www.PaulRoark.com