Sharpness, contone (was Re: Useful results from gum tests

John, what do you mean by "acceptably sharp"? Since sharpness is
anathema to me (in fact I just spent $$$$$ on a soft focus portrait
lens) it hurts me to have my work labeled "sharp."
  ;--)

But, for the Peter Marshalls of the world who are still saying that
gum doesn't print continuous tone well (another of those gum myths)
I probably should have specified that that dead seagull negative that
I use a lot for test prints, and that I used in the tests referred to
here, is a continuous tone 4x5 negative.

There's a page on my website that compares continuous tone to a
stochastic dot for printing gum. It's not quite the same as
halftone, which is what Peter was suggesting the other day would be
the best kind of negative for gum, but it does address the more
general question of whether dots are better for gum than continuous
tone.

http://www.pacifier.com/~kthayer/html/dotcont.html

Katharine

On Apr 11, 2006, at 8:34 AM, John Grocott wrote:

> Katherine, May I say, but not as a gum printer, that I found your
> three examples extremely impressive especially when I printed them
> on glossy photo quality paper. The last one looks acceptably sharp
> which you printed on paper, ''on a somewhat less- pigmented gum
> emulsion''. I join with
> ----- Original Message -----
> From: "Katharine Thayer" <kthayer@pacifier.com>
> To: "alt photo" <alt-photo-process-l@sask.usask.ca>
> Sent: Monday, April 10, 2006 7:33 PM
> Subject: Gum hardening: top down?
>
>
> > Okay, I've coated a very thick, very heavily-pigmented gum
> emulsion on
> > mylar and printed it from the front and from the back. A couple of
> > comments before I give you the URL:
> >
> > (1) though the emulsion was very heavily pigmented, two things
> resulted
> > in not a very deep DMax: (a) the fact that I used ivory black, a
> > transparent pigment (if I were to do it again, I'd use lamp
> black) and
> > (b) the fact that it's printed on a transparent material and was
> scanned
> > as a transparency, with the light shining through it. But the
> thing to
> > note is, be that as it may, the DMax is about the same in both
> prints.
> >
> > (2) there's a light brown pigment stain (ivory black is a
> brownish black)
> > in both prints that is probably a function of the heavy
> pigmentation. It
> > hardly shows in the prints themselves, but for some reason was
> > accentuated in the scanning.
> >
> > (3) I don't honestly know what to make of the results. If you
> look just
> > at the prints on mylar, you'd have to conclude that back-
> printing is much
> > superior to front-printing, at least for a thick coat on mylar.
> But if
> > you compare the back-printed print on mylar to the regular front-
> printed
> > gum print (using a less heavily-pigmented emulsion) on paper (at
> the
> > bottom of the page), it's hard to claim that the back-printed
> print is
> > superior. But since they are on different materials, it's apples
> and
> > oranges.
> >
> > So I guess if I were forced to draw a conclusion from this rather
> > inconclusive test, I'd say that if you are going to print on
> mylar using
> > a very thick and heavily pigmented emulsion, then you'll
> probably do
> > better printing from the back. But if you're printing on paper,
> you can
> > get fine results printing from the front with a less pigmented
> emulsion.
> >
> > http://www.pacifier.com/~kthayer/html/topdown.html
> >
> > Katharine
>
Received on Wed Apr 12 09:29:28 2006