Digital BW, The Print

I agree with you that acid-free EEM is worth pursuing. In the best of 
all possible worlds EEM would go back to EAM.

Chris Hargens

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul Roark" 
<paul.roark@v...> wrote:
> Short version:
> 
> The Wei To #12 spray, in initial tests, deacidified the EAM/EEM 
sample
> through the entire paper base.  The sprayed sample is now "acid-
free."
> 
> The long version:
> 
> My favorite paper continues to be EAM/EEM -- if it were only really
> archival.  Unfortunately, it is not because it is acidic.  It is 
made of
> un-buffered wood pulp, which, unlike cotton, has lignin in it that 
turns
> acidic when it is broken down through oxidation.  Unfortunately, 
while the
> lignin content of EAM/EEM appears to be very low, it is apparently
> impossible to totally remove it from wood-based papers.
> 
> The acidity will eventually attack the cellulose and destroy the 
paper, but
> this will take many years.  Epson and others have said that the 
acidity is
> also what causes the paper to turn yellow after a number of years 
(30 - 65
> seems to be the range).
> 
> Lignin by itself, even if buffered, is photo-sensitive and will 
yellow with
> UV exposure.  I have put test strips right next to a UV lamp for 
100 hours
> and observed no yellowing in EAM.  An informal, preliminary test by 
a person
> in the preservation industry also saw no signs of lignin.
> 
> Buffered wood-based papers can be archival.  The buffering simply 
mops up
> the acid's H+ ions before they can do any harm.  If there were no 
acidity in
> EAM/EEM, it might be quite archival.
> 
> I use an Abbey test pen to test for acid.  When it hits acid it 
turns
> yellow.  When there is no acid (H+ ions), it turns purple.  The 
untreated
> EAM/EEM paper base turns yellow.
> 
> Even cheap, wood-based paper is often buffered and turns the test 
pen mark
> purple.  Buffering is cheap, so it is a little surprising that 
Epson did not
> buffer EAM.
> 
> On the other hand, Epson may have chosen not to buffer EAM/EEM for 
some very
> good reasons.  One article I read indicated that a better gamut can 
be
> achieved if there is no buffering.  EAM/EEM's relatively good dmax,
> light-fastness, non-flaking, smoothness, or other performance 
characteristic
> might relate to the acidity or lack of buffering.  I have no idea 
what was
> behind Epson's decision not to buffer the EAM/EEM paper base.
> 
> There is a small "deacidification" industry that caters to 
libraries and
> other conservation and preservation-oriented organizations.  Claims 
of 300%
> longer life for acidic paper documents and artwork are often tossed 
about.
> 
> My thought is to simply buffer the EAM/EEM prints after printing.  
If a
> spray on the back causes the paper to test as non-acidic, and it 
stays that
> way for a reasonable time, we might have the superior performance 
of the
> un-buffered paper with a life-span that is very long indeed.  In 
fact, if
> the print is not dry-mounted or coated on the back, it could be re-
buffered
> if it ever tested as acidic many years down the road.
> 
> I have tried the Preservation Technologies spray.  It deposits a 
buffer on
> the back of the print.  Unfortunately, the buffer does not 
penetrate the
> paper.  As such, the back tests as non-acidic, but when ripped 
open, the
> interior fibers still show yellow with my Abbey test pen.
> 
> I just tried the Wei To spray -- #12.  It appears to soak into the 
paper.
> One slow sweep of the spray across the back is enough so that the 
interior
> fibers are testing non-acidic throughout the paper.
> 
> In the past, I've been able to de-acidify EAM with ammonia.  
However, the
> gas leaves no buffer.  So, those samples turned acidic again in a 
matter of
> days.  The Wei To leaves a buffer that should keep mopping up the 
H+ ions
> for some time.  The question of how long and how much buffer is 
needed in
> the interior for a reasonably long life is unknown.  I'll be 
testing the
> sprayed samples and exploring that issue (among others) in coming
> weeks/months.  The company probably has some information that will 
help.  I
> think the potential user base here is large enough for the company 
to pay
> some attention to the issue.
> 
> Acid-free (cheap) EAM/EEM -- it's worth pursuing.
> 
> Paul
> http://www.PaulRoark.com