Digital BW, The Print

Ernst,

> You will continue this test?

Yes, probably at a later date.  I'd like to add some new test strips to look
at some other factors, however.

>  Wonder whether the lower
> density loss in the blended set is a result of the energy gone
> in the toner fading and that a longer exposure will bring the
> same density loss for both samples after all. The toner loss
> is so similar in both examples.

I expect the fade rates to stay about where they are, but I, too, was a bit
surprised at the divergence of the fade v. tone shift.  However ...

> Is there also a measurable shift in the paper itself?


I think the answer may be in the paper.  I, unfortunately, don't have a good
0% EEM paper change for the 1344 hour fade segment.  On the other hand for
600 hours in the first part of the test with the 4800 v. UT7 test strips, I
did have some paper white.  The EEM Lab change was -0.04, 1.4, 4.48.  By
1944 hours this change was 0.05, 2.03, 5.72, as reported in the first post.
In that first post, the total color change for EEM was so much larger than
for Premier Art (non-OBA, acid free paper) that I'm wondering if we're just
seeing the paper affects here.  In retrospect, I wish I'd used Premier Art
for all the tests.  We'd never use EEM for a serious print, so why bother
testing it.  I had thought it would be representative of other papers, but
for color changes it appears not to be.  The fading, on the other hand,
seems to at least have some correlation to others.

 
> I actually expected that the blender mix would keep its tone
> better and the density loss  would be the same, shows that
> tests tell more than theory.

It may be that the perimeter or outermost color pigs are fading and becoming
transparent.  In a blended ink, when they become transparent, what mostly
shows through is the carbon (black).  With separate dots, what shows
through, at least at the edge of the pile of color pigs, and where they are
on paper and not previously laid down carbon ink is the paper (white). 

> Of all the fade tests you have done so far, how well did the
> MIS colors behave compared to the UC sets in general?

I mostly do B&W testing, so I can't really say how the color pigments
compare.  Also, given what we're seeing in the relative tone shifts, I'd say
there is a good chance that the paper used might significantly affect the
relative color pigment performances.  So one would have to be careful to
test the color pigs on the paper that was of interest.   

I would not read the significantly lower MIS ABW yellow shift relative to
the 4800 ABW sample on EEM as suggesting the MIS color pigs are tougher on
EEM.  It might be just the opposite -- the lower MIS ABW warm shift might be
due to more yellow pigment fade and a greater "counter-shift" affect.  I'm
just speculating here, but the point is that I would not draw conclusions
about color ink stability from these tests.  I think a proper test would
have the colors by themselves on the paper of choice, and for serious work
that paper of choice is not EEM.

I do think there may be a bottom line here for the B&W purists, however.  If
fading is a prime concern (and for many I think it is), the Epson ABW mode
may not be the best way to go.  If future tests are consistent with this
one, there will probably continue to be a small niche, dedicated B&W ink
market even at the high end -- something that I would have had serious
doubts about if the blended ink had not shown significantly less fading.
Jon Cone in particular should benefit from this apparent result.  (MIS would
do fine on entry level and all the other products regardless.)  These
results, however, need to be verified in longer term tests and on better
papers.

Paul
www.PaulRoark.com 

_____________




> Paul Roark wrote:
> 
> > Next, Ink Jet Control was used to print with the 2400 and MIS ink, but
> no
> > yellow was used.  As such, while the print tone was matched reasonably
> well,
> > less color ink was used for the print.  The goal here was to see what
> impact
> > the ABW mode's use of the excess color inks has on lightfastness.
> >
> > MIS IJC control:  59.82, 0.71, -1.45
> >
> > MIS IJC test:      60.15, -0.17, 0.99
> >
> > MIS IJC change: 0.33, -.88, 2.44
> >
> > (Notice the much higher yellow shift, due, I believe to the lack of
> > relatively fast fading yellow inks in the mix.  A fast-fading yellow was
> > used by me in the original FSN as a "counter-shift" strategy to offset
> the
> > warming of that older generation of ink.  I don't recommend such a
> strategy
> > for modern inks, however.)
> >
> > Finally, the same MIS pigments were used in a blended, dedicated B&W
> ink, in
> > this case made for the C86 just for this test.  The point here was to
> see if
> > the color inks mixed in with the carbon produced different results than
> if,
> > as in the IJC test above, the color inks were applied as pure colors in
> > separate dots.
> >
> > MIS blended B&W control: 57.13, 0.47, -2.01,
> >
> > MIS blended B&W test:     57.36, -0.42, 0.34
> >
> > MIS blended B&W change: 0.23, -0.89, 2.35
> >
> > (Note almost the same tone changes as the IJC, but with less density
> loss.)
> >
> > So, it tentatively looks like, at least on EEM, the ABW mode's use of
> the
> > excess color inks might cause increased fading, but more tone stability.
> > The inks being blended in a dedicated B&W inkset may lead to even less
> > fading.   While this is just one initial fade test, it looks like the
> > ultimate lightfastness may be from the dedicated B&W inksets.
> 
> Paul