Digital BW, The Print

----- Original Message -----
From: "Robert Morrison" <rmorrison@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Sunday, September 01, 2002 6:07 PM
Subject: Re: [Digital BW] PiezoTone Selenium 300 Hr Fade test


> On 9/1/02 4:30 PM, "Paul Roark" <paul.roark@...> wrote:
>

(big snip)

> Yes, but they are the same ones that we have all seen posted on the
> piezo3000 list at 100 hours.  In speaking to Jon, I know that he is having
> the full RIT testing done...and that the results are well out beyond 300
> hours using their Xenon source and that the inks set hasn't failed
yet...but
> RIT standards.

Robert,

That has always been the question. RIT standards or Wilhelm standard. From
the published info on the MIS tests in '99 they consider 65% retention to be
the fail point. That seems really low to me. I would much rather see the
CYMK density graphs than to get a "display life" value. I suspect a lot of
us would consider a 5% or 10% image loss a failure.

While Paul's tests don't give us a specific value for print life they do
give us very real head-to-head comparisons of the materials.

The results on the Selenium PiezoTone are pretty disappointing since I like
the inks so much. The failure of the black in the Warm Neutral PT set was
not so disturbing since no unpleasant crossover was created. I think that
this is a much more serious issue than the current blue separation in the
1280 cartridges Jon has been posting about.

Also thinking back to Jon's Xenon fade test of the prints compared to Paul's
fade test of the wedges I think the same warm/fade phenomenon is evident
although we do not have any sensitometry data from Jon.

As you and I have discussed off list, there may be issues of activation
energies in the warm/fade reactions. You have broader experience in the
coatings industry than I have, what do you think the basic reaction is in
the warm/fade? A simple oxidation of the pigments accelerated by photo
energy or something else?

At a guess the Xenon is more broad spectrum than Paul's fluorescent tubes.
Given the same flux I would expect the higher UV content source to be more
damaging.

Martin Wesley