From: Judy Seigel (jseigel@panix.com)
Date: 01/27/03-02:24:58 PM Z
On Mon, 27 Jan 2003, H. Lee Pratt wrote:
> Second: I too have an Epson 3000, which I have dedicated to b&W work,
> using the PiezographyBW drivers and inks. My understanding at this
> point is that you only need a "curve" if you are making a contact
> negative through a service bureau = using lithographic film. I doubt
> you will need any curve to make a desktop negative on your Epson, as
> you can simply invert your final image to a negative and print it to
> your 3000 on Pictorico OHP film. (Epson transparency film does not
> work, but the Pictorico product does.) If your positive looks good on
> the screen, the negative will probably print well on #2 paper.
Lee, this sounds as if you're making a digital negative for contact
printing silver gelatin, in which case it's possible you may not need a
curve (tho I gather so far mostly on AZO, from which you can't
generalize... SG however, often has variable contrast filters, which hand
coated does not.)
But be advised -- each ink, each printer, each substrate and each setting
put out a different "curve" from a digital printer... which is one reason
canned readymade curves are a chimera... They're given for the target
emulsion, that is, for instance, as "a curve for platinum," and even for
that my guess is it would be chancy, because of different contrast ranges
by paper and mix for platinum.
So the advice that comes with the curves is that you have to "tweak them"
-- well, like you can "tweak" your lover? INE, it's much better to start
with the right lover to begin with, that is, make your own curves to match
your monitor, your printer, your ink, your input, and of course your style
of printing.
> For gum bichromate, I understand that one needs a negative of normal
> contrast, again producible without any special curve. I too am
> interested in gum printing, which I believe Dan is going to cover in
> his workshop.
What is "normal" contrast for a gum negative ??? you're talking silver
gelatin again, and even there, "normal" is not a measurement. It's much
less serious with gum, because gum has infinite contrast controls in
printing, although if you want to do one-caot gum you most definitely
would need a curve at some point or level. That is, one coat won't do more
than, say, 6 steps on the 21 step, which is hardly "normal" for SG. So how
would you get your digital printer to print the negative for whatever
number of steps you want? By adjusting the negative in photoshop (or the
positive)? So that's doing the curve one at a time. It's OK -- but I
think you learn more if you apply a curve and then "tweak" it as you
print, either turning out another or with the next photograph.
PS. If I seem a bit adamant on this subject, I got that way after an
intensive care program, much too much time, investigating and then
deciding/declaring don't be helpless like baby birds in the nest, waiting
for big bird to feed you a worm -- make your own curve, and yes writing it
for P-F. Maybe by the time folks read it & pick up my mistakes they'll
have forgotten this assurance -- but the fact is, curves out there may not
be perfect, but they're not busywork. They serve a real purpose. It's just
that one size fits all less than ever with the growing diversity of
substrates, inks, printers AND media.
PPS. My impression is that studio printers use service bureaus for digital
negatives much less now that they have (1) Pictorico, and (2) new cheap
home printers, not to mention (3) Burkholder, and all that CIS jazz.
warm cheer from 17 degree fahrenheit NYC
Judy
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