Digital BW, The Print

----- Original Message -----
From: "Paul Roark" <paul.roark@...>
To: "DigitalB&WPrint" <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Saturday, September 07, 2002 8:43 AM
Subject: Re: [Digital BW] Re: UltraChrome 100 Hr Fade test


> Dan and Martin,
>
> It sounds like Royce was talking about a yellowing that is different than
> the optical brightener yellowing we've become familiar with -- and
> (personally) not much concerned with.  If Royce is correct, then EAM may
> have more problems than I thought.
>
> Do we know where the information on the effect of the slight acidity is
> coming from?  That is, how authoritative is it?  Also, how serious is it?
> If, like the OB yellowing, we're talking about 0.02 units of yellowing and
> then stabilizing, then it may still not be a major issue.

Paul,

I have never seen any measurement of the acidity of EAM other than pH pen
tests which do not have a high degree of accuracy. As I have posted before,
an unbuffered but acid free paper may test "acid" with these pens. The
result is inconclusive as to presence of free acid in EAM. It may or may not
be there. If it was truly yellowing from acid content I would expect it to
be happening much faster than it seems to be the case in these fade tests.

However, I think that it is likely that Epson's "Archival" designation may
be related to image permanence rather than paper permanence and if the image
permanence is not longer as good as initially believed then the name change
is appropriate.
>
> Incidentally, the yellowed 1850's era prints by Gustave Le Gray at the
Getty
> are just spectacular.  (Not that I'm in favor of yellowing, but in those
> photos its very appropriate.)

Are these albumen prints with a gelatin made from egg whites? They are known
to yellow. Even modern albumen prints do the same. Gustave might be very
disappointed if he was still around.

Martin


>
> Original messages:
>
> Dan wrote:
>
> >> The UC inks may last 75-100 years, but the Enhanced Matte paper will
> >> begin to yellow at 30 years, at least according to Royce Bair at
> >> inkjetart.com; I quote him here:
> >
> >> "The Enhanced Matte image permanence drop ...
> >>30 years vs. 75 years (with UltraChrome inks) and the 30 years
> >> vs. 100+ years (with the Archival Inks) is due to paper YELLOWING.
> >> Within about 30 years,...
> >> Enhanced Matte paper will yellow due to the paper's slightly acid
> >> pH.  The image itself, will not start to show noticeable fading
> >> until about 75 years (UltraChrome) or about 100+ years (Archival).
>
> Martin wrote:
>
> >... The yellowing in the Archival Matte and
> >other papers with optical brightening agents is due to the OBA's loosing
> >there ability to fluoresce. Robert Rex of Crane paper posted information
on
> >this quite some time ago. Once the OBA is exhausted and has yellowed it
is
> >stable and does not appear to effect paper life. ... the top silver fiber
> >papers seem to use some OBA's too.
>
>
>
>
>
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