U of S | Mailing List Archive | alt-photo-process-l | Re: Paper negatives- Ink Selection&Baden-Baden

Re: Paper negatives- Ink Selection&Baden-Baden

Couldn't agree more.

On Oct 14, 2008, at 3:25 PM, henk thijs wrote:

I did a lot of paper- and Arista half tone negs; i used negatives
for cyanotype, gum and oilprinting and i was very often astonished
about two things:
the unpredictable (and often astonishing) results ;
the forgiving aspects of too long or too short exposure times doing
It was the list who first mentioned the dramatic effect on exposure
times due to humidity; so i have some experience and do not trust
any specific rules in order 'to make the perfect gumprint or
equivalent'; i measure the amount of paint by eye, vary the
exposure by looking a bit after the humidity, downloaded some 3
dollar tutorials from Dans Burkholder website for my printer
settings and let it go.
Isn't that the way an apple pie is done after years of experience ?

Baden-Baden Horse racing Oilprint on 350 grs Fabriano nr 5 with
inkjet-plotter-foil negative (exactly same exposure compared to
paper neg ):


On 14 okt 2008, at 23:05, Katharine Thayer wrote:

Loris, my question was a simple question: on what are you basing
the statement that your exposure times are shorter than others'?
because I'm not seeing other gum exposure times in the thread,
never mind that even if there were, no valid conclusions could be
drawn from the comparison. Instead of answering the question
by pointing to posts I missed, or describing the data on which you
base the assertion, you simply repeated it. It's not a helpful
answer to the question, but I won't pursue it further; I'll take
your word that there are these people you know about, somewhere,
who print exactly as you print, with exactly the same emulsion,
same paper, same light source, same negative media and exact same
working procedures (same environmental conditions, we would also
have to assume) who have to use longer exposure times because
they're using negatives with more DR, or they're not calibrating,
or their calibrations are flawed somehow. This is quite a
remarkable finding, as I've never met two gum printers who use the
same everything, unless they happen to be taking a workshop
together and are using premixed emulsions and all other materials
and equipment supplied by the teacher. Oh well, I don't really
care, I was just curious. Back to check on my print,

On Oct 14, 2008, at 11:08 AM, Loris Medici wrote:

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
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

Hope it's clear, and makes more sense to you now. I perfectly
the confusion I may have caused on your part.


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
not useful to try to compare exposure times because there are so
variables involved, but putting that aside for a moment, I've
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
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
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
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
how it is with the system I use, and I assume it's the same with
systems; the curve doesn't change the exposure time. Besides,
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.

On Oct 12, 2008, at 11:23 AM, Loris Medici wrote:

I use the grayscale using all inks (not black and gray - if
- 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
collection for many processes and paper. In fact, I think that's
why other
people's exposure times are considerably longer compared to