Digital BW, The Print

I don't have a 100% solution to this problem yet, but there is some news to
report.

First, the Bookkeeper spray on the back has not raised the pH of the
interior fibers enough to see a difference with an acid test pen.  It may
never, but that may be more about the limited test abilities of the pen than
the effectiveness of Bookkeeper deacidification spray.

The maker of Bookkeeper has not tested EAM yet.  They have purchased some
and will get to it when time permits.  Hopefully their tests will tell us
more about whether the acidity can be lowered enough to stop the yellowing.

Ammonia does deacidify EAM.  Ammonia is a gas -- NH3 -- that is usually
dissolved in water for household use.  It is an effective deacidification
agent.  Not only does a weak liquid solution totally deacidify the entire
EAM, but the fumes alone do it.  I put an open cap-full of household ammonia
and an EAM sample in a zip lock bag overnight.  By morning, the entire
EAM -- surfaces and interior fibers -- tested as acid-free with the test
pen.

So, I've found an easy way to deacidify EAM.  However, there are at least 2
caveats.  First, ammonia gas does not leave a buffer.  So, while the EAM may
be "acid free" today, whatever it is in the EAM that is causing the acidity
may re-acidify the paper quickly.  Second, the de-acidification may affect
printing -- lowering the dMax among other things.  I'll test this soon.

On the back of one of the ammonia-deacidified test strips I've sprayed
Bookkeeper, which will add a buffer at least to the back of the paper.  My
testing ability with the pen limits the extent that I can measure the change
in pH of the interior fibers.  That plus uncertainty as to what pH level
causes the yellowing may stop us from ever having hard information on the
long run effectiveness of deacidification procedures.  However, these easy
procedures may do enough to put the yellowing problem off so many years that
it is a moot issue.

Speaking of yellowing, my fade testing suggests that the new batches of EAM
may have fewer optical brighteners.  At least the yellowing I see in my fade
tests appears to have been reduced.  I think that Epson changed the coating
formula to lessen the yellowing -- with the unfortunate lessening of the
dMax.  Perhaps they (also?) put (more?) buffers in the coating. (The coating
has never tested as acidic the way the paper base does.)

Paul
http://www.PaulRoark.com