Digital BW, The Print

The ammonia deacidification does not affect the printing at all from what I
can tell.  The dMax, etc. is the same as with a non-treated EAM.

Paul
http://www.PaulRoark.com
_________________________________
  -----Original Message-----
  From: Paul Roark [mailto:paul.roark@...]
  Sent: Tuesday, October 29, 2002 8:40 AM
  To: DigitalB&WPrint
  Subject: [Digital BW] EAM Deacidification


  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



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