Digital BW, The Print

----- Original Message -----
From: "Martin Wesley" <mwesley250@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Saturday, September 07, 2002 7:15 PM
Subject: Re: [Digital BW] Re: UltraChrome 100 Hr Fade test


> ----- 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.

I have seen that comment on acidity/yellowing by Royce in the 9000 list some
time ago. I find it a bit confusing. The results given by Wilhelm are based
on his use of 60 % humidity in the test, the temperature in Wilhelm's tests
is not below room temperature (I guess). If the paper yellowed in the test
he would have made that clear. The tests are not on ink alone but for a
given ink/substrate combination. It is of course possible that a higher
degree of humidity and temperature will change the paper colour faster.
However Wilhelm's test conditions are already considered severe if compared
with museum conditions. I have made the same comment on the 9000 list then.
Royce answer was as follows:

"According to my recent talks with Henry W., all aspects of image
permanence are now being carefully considered, which is why
Epson is now calling the results of his tests "Image
Permanence" testing vs. just "Lightfastness".  This is why the
results on the Enhanced Matte are dual (30/75) and annotated."

Ernst