Re: Modified Zia Formula


Carl Weese (cjweese@wtco.net)
Fri, 21 May 1999 11:02:09 -0400


Jeffrey,

While your results are interesting I think I should point out that they
are beginning to make ziatype sound like a dark and mysterious process
requiring arcane knowledge to master, when in fact it's the easiest and
simplest way to make world class Pt/Pd prints. Maybe I should point out
here as well that I have no financial stake in this. I have no
connection to B&S and don't make a penny when they sell a kit.

Basically your tests are searching out the best way to overcome the
mistake of using too much solution. I found (and reported here) that the
best ziatypes--especially on the Crane paper you are using--result from
using just 12 drops each of afo and metal solution (half what you are
using) applied with a glass or acrylic rod. More solution applied with a
rod is wasted, it just doesn't go into the paper. More solution applied
with a brush results in a worse print. As far as I can tell this
phenomenon is specific to zia. When I ran across it I immediately made
similar tests with traditional develop out materials and found that at a
certain point, using more solution stopped improving the result, but it
did not cause results to worsen. Experience with one method can't be
assumed to hold true for the other.

55% RH also seems the ideal working environment for zias on this paper.
A workroom wetter than this makes platinotype very difficult to use
(though other papers, notably Arches Platine, work wonderfully at
humidity levels up into the 70's but crash and burn below 60%).
Especially with large print sizes, working with zia and platinotype at
humidity over 60% is an exercise in frustration. In a dry environment,
"misting" the sheet just before coating and placing a plastic dam in the
print frame will take care of things just fine.

It's also important with this paper and zia to use forced air for a
quick dry after coating. Just hanging the paper on a line for a while
(which works great with several other papers) assures grainy prints. I
suspect a variation of this effect is behind the graininess you report
from your tests that are coated super-wet and then printed in an extra
high humidity environment. It may simply be the long drying time you
mention.

You've also set an arbitrary exposure time. This simply defeats the
purpose of a full POP process. Judgement of what makes the "best" print
should utilize the process control of POP because that's how we'll
actually use the method in practice.

The test I'd like to see would be this. Compare results with your
modified metal formula to the original out of the bottle formula,
coating both in the way I've already determined is best for this paper
with that standard formula--24 drops total solution applied with a rod
to humidified paper. Use the POP nature of the process and print not for
a standard time but for best visual result, and process in the normal
zia manner which involves no separate developer step. If the new,
metal-rich formula results in "better" prints, great. If the prints in
this test are in fact inferior to the ones you are getting with the
procedure you describe I'll be quite surprised, but delighted at the
discovery of a way to make better prints.

---Carl



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