Re: Dryingtime before profiling matte paper
Re: Dryingtime before profiling matte paper
- Subject: Re: Dryingtime before profiling matte paper
- From: Ernst Dinkla <email@hidden>
- Date: Sat, 15 Jan 2005 13:28:02 +0100
bruce fraser wrote:
Ultrachrome shifts, not as much as dyes, but it DOES shift while it's
curing. You probably won't see it with the naked eye, but it's
measureable and consistent.
The vast majority of the shift happens in the first couple of hours, and
is strongest in the dark greens and reds (black loses a little density,
and the C, M and Y shift hue in different directions, so it's a bigger
shift than you'd notice from just measuring the solid primaries).
Typical worst-case patches shift by about 1.4 delta-e over the first
12-18 hours depending on the paper, which is too big a shift to be
attributable to instrument drift (my ICColor and SpectroScan both seem
consistent within about 0.1 delta-e), and is just enough to be of
concern when you're measuring a profiling target.
I usually let profiling targets cure for 24 hours to be safe-after that
they're rock-solid on all the Epson papers. It may be overkill, but I've
found that a 1.4 delta-e error in the profiling target can translate to
a 3 delta-e error in the profile. 3 delta-e in a dark green is still
quite hard to see unless you know it's there...
Bruce
I have seen a Black density increase within 12 hours for the
Epson Archival pigment and the MIS7600 Eboni black pigment
inks on Hahnemuhle coatings. Are you sure that there's a drop
in Black density ? Pure Black samples measured though and the
effect may differ per coating.
I've asked this before: Are forced drying methods with warm
air delivering differences to the normal drying process = other
measurements ? One of the aspects could be a longer period of
bleeding into the coating in the normal drying process.
Are differences of 0.3>0.4 delta-e per sample between multiple
target (row) readings normal ? That's 3x the instrument drift
of 0.1 delta-e but I guess the last is measured on fewer samples.
Ernst
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