Digital BW, The Print

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.

> ...

> 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.

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.

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.)

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.

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.

Paul
http://www.PaulRoark.com