Re: Paper negatives- Ink Selection
That's interesting, Guido, thanks.
What's puzzling to me, in light of your observations, is that when I
switched from greyscale negatives (printed with color inks) to color
negatives, using Michael Koch-Schulte's NLP array to determine the
color, it didn't change my exposure times for gum at all. But, now
that I think of it, I made that change fairly close in time to a
change in printers, from the Stylus Photo EX to the Epson 1280, so
it would be impossible to draw any valid conclusions about the two
kinds of negative, because they weren't made on the same printer or
even on the same media (my greyscale negatives were oiled paper
negatives, but my colorized negatives are all on transparency film).
But one thing I've noticed is that with the colorized negatives, I go
through color cartridges like nobody's business. Although, again,
it's a different printer, and maybe this printer would also eat
cartridges with greyscale, even though the old one didn't. Too many
variables. But anyway,
thanks again.
Katharine
On Oct 14, 2008, at 11:37 AM, Guido Ceuppens wrote:
Since the original post questioned the list on their ink settings I
did another comparision:
my previous post gave MY exposure times in MY setup using oiled and
un-oiled paper using a colorised negative, so I now did a furter test,
again with cyanotype (cheap and quick) using Chartthrob.
A Grayscale_Chart printed with a color 0;255,21 printed OK with an
exposure of 8 mins (ChartThrob white at 2, black at 100).
A Grayscale_Chart printed with All Inks needed an exposure of 24 mins
to arrive at the same density/tonal scale (ChartThrob white at 2,
black at 99).
Funny enough the resulting curves were almost identical. I print with
an Epson 1290 using third party inks on Epson PQP oiled.
So does a correctly colorised negative aid in more speed when
printing? For me, maybe yes, but an all inks setup might be (a lot)
cheaper, especialy when using Epson single-color cartridges
Guido
2008/10/14 Loris Medici <mail@loris.medici.name>:
Katharine, don't worry I'm pretty careful about this subject -
knowing (by
experience) you'll chime in every time it's brought up, to
clarify ;) I'm
getting older I guess; less and less surprises... ;)
I wasn't attributing the short exposure I'm using to curves at
all, that
was a side note (which should have been enclosed between parenthesis,
sorry). I was trying to say (indirectly) that since the DR (=density
range) and tonal progression of my paper negatives (made with the
HP 9180
all-inks grayscale setting, using the printer's plain paper
profile) are
close to ideal (in tricolor gum printing context - which is
supported by
the fact that the curve I devised for this particular combination
is the
smoothest and least dramatic one among all curves I did until now),
therefore, other people's longer exposure times could be caused by
the
fact that they're using negatives with more DR, which naturally will
require more exposure and a stronger / more dramatic curve to
counterbalance. Or they're not calibrating, or their calibrations are
flawed...
Hope it's clear, and makes more sense to you now. I perfectly
understand
the confusion I may have caused on your part.
Regards,
Loris.
P.S. BTW, I have compared my times with the times of people who use
similar light source, emulsion, negative media and working
procedures. I'm
perfectly aware of the parameters affecting exposure time and pay
attention to them.
14 Ekim 2008, Salı, 7:18 pm tarihinde, Katharine Thayer yazmış:
Loris, I'm wondering what data you're basing this last bit on, that
other people's exposure times are longer than yours. It's
generally
not useful to try to compare exposure times because there are so
many
variables involved, but putting that aside for a moment, I've
looked
back through this thread, and the only reference to exposure times I
can find is Guido's comparison between oiled and unoiled Epson PQ
paper, 8 vs 48 minutes, with cyanotype. Since it was cyanotype,
and
since the paper is a heavier paper (27 pounds) than yours, it's not
surprising that his exposure time for unoiled paper would be longer
than yours, and we haven't even got to light source yet; to reach
immediately to curves to account for a difference in exposure times
seems rather a long stretch to me.
Perhaps I've missed other posts that included exposure times for gum
and paper negatives (my server doesn't accept some of the alt-photo
mail, so I don't always see all the posts). At any rate, my times
with oiled paper negatives run close to my times with inkjet
transparencies, about 3 minutes, to add to your database on
exposure
times. I don't have any comparison with unoiled paper to offer,
because that's not an option that makes any particular sense to me.
But be that as it may, I can't see any reason why curves would
account for a difference in exposure time. After all, the exposure
time is determined before curves are even calculated, at least
that's
how it is with the system I use, and I assume it's the same with all
systems; the curve doesn't change the exposure time. Besides,
curves
simply redistribute the tones within the print tonal range that
particular emulsion can print under that particular protocol; they
don't extend it, so there's no logical reason curves would have any
effect on exposure time.
Katharine
On Oct 12, 2008, at 11:23 AM, Loris Medici wrote:
I use the grayscale using all inks (not black and gray - if present
- inks
only), plus, I choose plain paper as the media. Fortunately, with
my inks
the printer lays just enough ink giving an almost perfect
negative in
terms of density range (something around log 1.0), and the curve I
use for
gum prints are is the least drastic and most smooth one among my
curves
collection for many processes and paper. In fact, I think that's
why other
people's exposure times are considerably longer compared to
mines...
(!?
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