Digital BW, The Print

Paul, Regarding you comments and dismissal of the Blue Wool Test, you
are out of step with virtually every major organisation involved with
testing colour materials for fading.  In my experience they all use the
Blue Wool Scale and Delta-E values.

Additionally, your assertion that you are not a competitor to Image
Alchemy also rings hollow.  In fact in your email to me of yesterday you
state, "... It's always good to see a new competitor".

Prior to deciding to manufacture our own inks, we approached a number of
different manufacturers including MIS Associates and you.  You might
recall that I spent an hour and forty minutes speaking with you about
the various merits of various manufacturer's offerings.  In fact I was
referred to you by MISA.

Anyway, I need to prepare for PMA, so I cannot comment again concerning
this matter.

Paul Banks
Image Alchemy Ltd
www.image-alchemy.com
www.image-alchemy.de
--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul Roark"
<paul.roark@...> wrote:
>
>
> > Our inks are tested to an internationally accepted standard
> > the Blue Wool Scale (BWS).
>
> I just want to comment a bit on the Blue Wool standard.  It has been
used by
> many industries for quite a while, but the Blue Wool test does not
appear to
> be the internationally accepted standard for photos or inkjet
pigments.
>
> Let me quote Lyson:
>
> "Lyson has a number of methods for observing pictorial image fading of
which
> Blue Wool and simple window placement are still carried out. However,
the
> test that we believe gives the most accurate prediction of actual
indoor
> display life is the method used by Wilhelm Imaging Research, Inc
> (www.wilhelm-research.com). The Wilhelm test criteria has, in the
main, been
> adopted into the 1996 ANSI (American National Standards Institute)
document
> 'Stability of Colour Pictorial Images', which itself is in the process
of
> being furthered into an ISO standard. By definition, this will become
the
> International test that our industry should orientate itself to."
> http://www.nazdar.com/Lyson/lyson-longevity.html
>
>
> I actually have the Blue Wool test materials and decided not to bother
with
> them.  I'm not saying they are not relevant, but they do not give
enough
> information to distinguish the inks, and testing to the end stage is
not
> what I'm most interested in and is not practical for me.  I do not
have the
> time to do that for enough inks and papers to allow me to move forward
at
> the speed this industry moves.
>
> Let's look at some actual numbers and equivalences.  The Blue Wool
rating of
> 7 is 300 megalux hours of exposure before fading becomes noticeable. 
(See,
> for example, http://www.handprint.com/HP/WCL/pigmt6.html#lightfast) 
This
> translates into 152 Wilhelm years of display.  (Wilhelm uses 450 lux
for 12
> hours per day.)  The Blue Wool rating of 8 (the highest) is 900
megalux
> hours of exposure before fading becomes noticeable.  This is 457
Wilhelm
> years of display.
>
> Most of the action with respect to the pigments I'm working with is
between
> the BW 7 and 8 ratings.  That is rather large gap -- from 152 to 457
Wilhelm
> years of display.
>
> It also would simply take me too long to test to the end points, and I
don't
> think that is my main interest anyway.  So, I test for shorter
periods, but
> long enough that the initial high non-linearity I've found with some
inks
> does not overwhelm the final results.  (Most of this is in the first
> "Wilhelm" year.)
>
> As an example, in one test a bit more than a year ago, I exposed
samples for
> what would be the equivalent of 13 Wilhelm years.  In this test the
MIS UT7
> did 2.8 times better (looking at the change in Lab L) than the K3 B&W
inks
> on Premier Art Hot Press (the same coating as UltraSmooth).  Wilhelm
rates
> the K3 B&W inks at ">205" years on UltraSmooth under glass (not UV
glass).
> So, could the UT7 inks really "last" 574 years in typical indoor
display?  I
> don't know, and I'm not going to do the testing needed to get to that
stage.
> That would, by the way, be a Blue Wool rating of 8.  In fact, Livick
did a
> test on coated UT inks all the way out to the end point.  He came up
with a
> rating of 681 years.
>
> Any accelerated test is subject to criticism.  They all introduce
factors
> that might skew the results one way or the other.  But when I see most
of
> the industry going to Wilhelm, that makes his procedures the de facto
> standards regardless of their merits.  In fact, however, my reading
and
> experience suggests Wilhelm is the best there is.
>
> At any rate, I simply want to point out that Blue Wool rating of 7 is
fine,
> but it does not tell me what I'm looking for.  It does not tell me
these new
> inks are any different than the others that are out there.
>
> I'd love to see a comparative test. I really hope you do have
something
> special.
>
> Epson's Claria "dye" inks demonstrate rather convincingly that
significant
> progress is possible and perhaps likely in this field.  The pigments
we use
> are called "dye stacks."  I wonder what happens when Epson "stacks"
the
> Claria dyes?  Would there be a huge (like 4x) improvement in the
pigment
> lightfastness the way there appears to be for the dyes in their
soluble
> form?  Would we be looking at color prints with "800 years" of display
life?
>
> Paul
> www.PaulRoark.com
>