Digital BW, The Print

Walt,

> I read your post with the fade figures and had a few questions on
> interpretation.
> 
> You gave hour figures and though there was a difference between the
> two ink sets, the *absolute* amount of fading was quite minimal on
> the K3, or so it seemed to me.  So I'm wondering what you think the
> significance of this is over real time.

I think all of the tested inksets are very good and would not have serious
fading in good display conditions for a very long time.  On the other hand,
we also know that in poor display conditions fading can be much faster.
It's not unusual for prints in real world display to get some occasional
direct sun.  Many are still skeptical that inkjet prints are really stable
enough.  So, the more lightfast the better as far as I'm concerned, and the
fact that the blended MIS inks had only 1/3 the fade of the k3 ABW, to me,
is significant. 

> Also your figures were for unglazed prints (I gather)

Yes.

> and I'm
> wondering about the effect of glazing on both the absolute and the
> relative figures.  I notice in Wihelm figures that glazing provides a
> protection factor varying from about 1.4 to 1.8, which is a big
> difference between paper/ink combinations.

I have no doubt the glazing helps.  I have no information as to whether the
relative rankings would change, but I frankly doubt it.


> Finally I wonder about the assumption of linearity--that early
> results will be linearly extended over time.  I expect these are
> curves.

All the information I have suggests the non-linearity is mostly at the
beginning of the process.  I doubt there is exact linearity, but I'm just
not going to worry about it for what I do. 

> I think you also mentioned that any "toning" with the Epson controls
> increases the use of color inks, but I'm not sure this is true, at
> least for certain colors.  In using an ABW setting of -12 -16 for the
> USFA (which gives a pretty neutral gray), the usage of yellow in the
> 4800 has dropped to about that of the cyan and magenta, which is say
> it is used mostly for cleaning cycles.  The light magenta and light
> cyan levels seem about what they are without tone adjustment.

I have not tried to quantify how much color is used for various settings.
The "neutral" ABW seemed like a logical one to use for comparative testing.
So, that is what I did.

I'm not trying to convince anyone that one inkset is better or worse than
another.  I do tests like this for my own purposes.  To the extent others
can glean useful information from them, all the better.  For my purposes,
the test answered the question of whether it was worth my time to make a
dedicated B&W inkset for the 2400.  It is.  So, I'll see what I can come up
with this next year.   

More, longer, and better testing would, of course, be even more helpful, but
life and resources are just too short to wait for such -- they just are not
going to happen.  So, I try to move forward with the best I can do within a
reasonable time.  

I think the more of these types of tests we have the better.  Sadly,
however, it appears some have become too concerned with pressure and threats
of litigation to keep their results on the web.  See
http://www.livick.com/method/inkjet/pg1.htm   Many probably thought Livick's
rating of a coated UT2 print at 600+ years as off the wall, but it's rather
in the same league with the relative performances I've seen.  The third
party B&W pigments that I've tested -- specifically the MIS UTs and
Piezotones -- appear to be very lightfast.  

Paul
www.PaulRoark.com