Digital BW, The Print

Hello Chip,

>That's a bit scary -- a Septone print showing signs of fading at 125 
>days?  (Yes, I understand that,  as you said, this is not the kind of
>test that simulates "real world" conditions, but geez...).  Could
>you define exactly what signs of fading you're seeing?  A general 
>fade in density of the whole image?  Blacks getting weaker?

The test print was sent to me by Septone as part of the review I did
last summer for the Technical Print Exchange.  Along with several
samples on EEM, they sent one on PhotoRag, and the ink mixture was 25%
warm/75% cool.  The print consists of 5 separate images, one being
Paul's enhanced wedge, which is the part I used for the test.

I taped a 5/8" strip of 4-ply matt board over the middle of the wedge,
for its entire length, partly over the smooth ramp and partly over the
steps.  

I put it on my front windowsill.  The large picture window faces south
and has an awning, so the sill gets bright daylight all day but is
protected from direct sunlight for most of the day.  The print gets a
little bit of direct sunlight early in the morning and late in the
afternoon when the sun peeks in under the edges of the awning.  The
room is A/C during hot weather (South Florida) and no A/C in winter,
so the humidity and temperature vary quite a bit.

I wrote the beginning date on the print and peeked under the matt
board strip every now and then.  At 125 days I first noticed some
fading.  The fading is visible from 7% to 98% on the wedge.  Visually
it is less dense and warmer.

The beginning date was August 28, so it has been over 7 months now.
I am looking at it now as I write this.  I don't have a densitomer so
I can't give any numbers, but my impression is that the fading is
worse now than it was when I first noticed it.  So it apparently is
worsening.

The Eboni BO print (oops, it's on EAM, not PhotoRag) is dated November
5th, over 160 days now, and shows no signs of fading.

I also have an UltraChrome print on EAM (grayscale print using Epson
2200 driver - Cyan/Magenta dots visible, with MK) that is dated
September 17, over 200 days, that shows no signs of fading or color
shifting.  

The UC color pigments are holding up like the Eboni so far.  This
leads me to conclude that

1) The UC color pigments are very resiliant

2) The Septone inks must be using some dyes or poor quality pigments
to do the toning

Bob at MIS said their inks use tiny amounts of pigments in the carbon
grayscale inks, so I expect to get good results when I test UT7.  

I'll continue to monitor the UC print but I still am uncomfortable
about those color dots.  Maybe they'll last for years, but if
Wilhelm's tests show that carbon inks outlast the pigments, do they
still rate as "archival"?  Is there a strict definition of that term?
 Can a RIP print be called archival if it shows color shifting at 70
years and a pure carbon ink print lasts 100 or more?


Regards,
Clayton


Info on black and white digital printing at    
http://www.cjcom.net/digiprnarts.htm