Smieglitz@aol.com
Date: 09/17/01-08:15:18 PM Z
Sorry for my incomplete previous post. Somehow AOL sent it off prematurely,
so to complete the thought...
David,
You bring up several questions that simply can't be answered with a "one size
fits all" response. I will comment that a good negative for producing a full
scale gumprint generally has lower contrast, much lower than a standard
negative for platinum printing or even silver gelatin. You can however
produce gumprints from high contrast kodalith negatives if you wish a
posterized effect. So, it all depends what you are after. Pyro may or may
not affect the gum emulsion in terms of contrast, but I suspect the speed
might vary due to the stain. (I'm not aware of anyone actually testing pyro
for use with gum printing, so take the previous statement solely as
conjecture on my part.)
You mention in-camera separation negatives and pigments for printing each of
the 3 negatives. It sounds like you are not color-separating here, but
rather separating for different tonal areas. If so, is your intent to
neutralize the colors and produce an essentially monochrome image with
slightly warmer/cooler shadows or highlights, or are you after a more
realistic full-color rendition? The latter involves an RGB or CMYK set of
separation negatives and not a set based on tone.
Either way, the choice of pigments as "good starting points" is pretty wide
open and various gum printers will recommend different brands or colors,
often with different experiences. As a general statement, I'd say most of us
try to print with transparent, non-staining pigments whenever possible.
Unfortunately, many of those staining or opaque pigments are also too
beautiful to resist and can be used with good result if one accepts their
limitations. Generally, pthalocyanine- or quinacridone-based pigments tend
to stain, some more than others, so individual tests are in order. Also, in
general, the closer a pigment is to white in value (e.g., many yellows), the
greater its opacity will be. However, there are exceptions. Daniel Smith
New Gamboge is a fairly transparent yellow in contrast to the often
recommended cadmium yellows which are more opaque. Likewise, a pthalo blue
will be transparent and a cobalt blue more opaque. Ditto with alizarin
crimson or a quinacridone red vs. a cadmium red. So, there are tradeoffs in
hue, transparency and staining potential that can only be decided by the
individual printer. Buy a few tubes and experiment, but look at the
transparency, staining and lightfastness ratings for any pigments you choose.
There are several internet sites that list pigment characteristics...I think
the last one cited onlist was in the watercolor painting section of a site
called "handprint.com" but most art supply shops will have pigment charts or
spec flyers if you ask for them.
Hope this helps.
And peace to all...
Joe
--- In a message dated 09/17/2001 15:05:36, nashcom@btinternet.com wrote:<<Hi
I've just watched Livick's movie on gum printing - I bought it a number of
months ago with an order of chemicals from B&S, and have only just watched
it. I've seen some not all that complimentary remarks over the last few
weeks, but it's given me the incentive to try gum printing. Until now I've
only done platinum, and I'm looking for a few pointers.
Ever willing to jump in at the deep end, I'd like to have a bash at
tri-colour printing. Firstly, I'll probably make in-camera separation negs.
What filter values will I need to use, and what pigments are a good starting
point?
I'm also wondering about negative contrast and density. Will a typical
platinum neg be too contrasty? Until now, I've developed in pyro, but I
assume the green stain will influence the colours. I'll probably try a
standard developer, but would like an idea of what contrast range to aim
for.
Also, will I need to make more than three print exposures? I've read
something about developing with yellow pigment for the highlights, then cyan
for midtones, magenta for shadow (I may have got these in the wrong order).
As ever, any help will be much appreciated, and apologies for any dumb
questions. I've never seen a gum print, but I hadn't seen a platinum print
before I made one, so I'm happy to give it a bash.
David Nash>>
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