Humidity and Ultrachrome inks stability
Humidity and Ultrachrome inks stability
- Subject: Humidity and Ultrachrome inks stability
- From: Roger Breton <email@hidden>
- Date: Sat, 26 Mar 2005 12:24:08 -0500
Working on my Epson 4000 printer profile these days. There is a change in
the printer colors that QualityMonitor, a companion application of
PrintOpen5, has revealed which prompted this investigation -- I'm starting
to really like QualityMonitor (I'll write about it separately, here, in a
separate installment).
So, I've outputted a few ECI2002 testcharts on this printer yesterday
morning to track the change in the inks appearance over time. So far, I read
the charts at two moments in time, once after 30 minutes of drying and once
again, this morning, after 24 hours. I am well aware that this issue has
been discussed many times, here, on the List and that one consensus shown
that these inks are rock solid after 15 minutes or so of drying.
I've setup a temperature and humidity meter next to the printer in my office
to start taking into account the effect of environmental conditions on the
color produced by my Epson 4000. I know some of my clients have full fledge
humidity and temperature controlled systems in the rooms where they placed
their 9600s and the likes, but I'm not prepared to go to that extent -- yet.
Still, I'm curious.
The temperature in my office, according to me new gizmo, is 22 and 32%.
After 24 hours, I am getting an average of about 0.37 DeltaE over the 1485
patches of the ECI2002 chart (stdDev 0.24 max 2.60), which isn't necessarily
bad. The largest deviations (2.60 and down) seem to be coming from the
presence of yellow ink in the mix:
dE C M Y K
----- |------|------|------|------
2.60 100 000 100 000
2.15 000 040 085 000
2.10 055 020 070 000
1.98 000 085 100 000
..
1.51 070 085 070 000
1.49 000 085 000 000
..
1.14 010 030 070 000
..
As this partial table show, wherever Yellow is present in a relatively high
concentration, there is a larger color shift after 24 hours. Magenta, on its
own, is also responsible for some shift, according to the result of 1.49
where there is only 85%M in the mix. This is puzzling. I wonder what others
are getting out of the UC printers?
One overwhelming conclusion I have no choice to come to, it seems to me,
from the above evidence, is that these inks cannot be profiled fresh or only
after 30 minutes of drying if one insists on the absolute, highest degree of
profiling accuracy (maybe I'm just spliting hair?). Unless these inks have
been shown to be more stable where the relative humidity level percent is
higher?
Roger Breton | Laval, Canada | email@hidden
http://pages.infinit.net/graxx
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