Re: Ziatype: how many coatings?

Thanks Jeffrey,

----- Original Message -----
From: "Jeffrey D. Mathias" <jeffrey.d.mathias@att.net>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Sunday, October 10, 2004 5:26 PM
Subject: Re: Ziatype: how many coatings?

> One coat will work fine. Although a few considerations:
>
> 1) It is possible that the print may not print out completely, especially
> if the relative humidity is less than needed. It is a good idea to use a
> potassium oxalate (or other) solution for full development.

I have sodium citrate - will that work as developer?

> 2) Make sure you have enough metal in your coating solution and your
> sensitizer is strong enough and not spread too thin. Some of the
> literature does not give strong enough formulas; feel free to check my
> e-guide from link below.

Your e-guide is great. But the detail is intimidating I must admit. Asking
this before looking your site: I have used a 40% ammonium iron(III) oxalate
solution. Do you think this is strong enough? As I said to Christian in my
previous message: the emulsion speed is very very high compared to Vandyke
or Cyanotype 2.

> 3) Each paper may require differing chemistry (I have not worked much with
> Whatman papers but have used enough others to always expect differences).

I didn't like the dmax I got from HP Whatman watercolor paper. Will try it
with my "usual" CP paper later.

> 4) Note that your negatives will print best if optimized for the printing
> process, meaning negatives that worked best with Vandyke may not be
> optimum for Pt/Pd. Even though a negative can give a good looking print
> with adjustments, an optimized negative might be even better.

I use digital negatives. So I will make test for every combination I plan to
use. I'm trying with a straight AFO + LiPdCl mixture for the moment. Later
will make experiments by dialing in Sodium Tungstate and Gold Chloride...

Another question (to both of you):

The print doesn't clear well. I used two tablespoons of citric acid to 2lt
water - it cleared the whites to some extent but there's still a veil in the
highlights. What can I do to effectively clear Ziatype?

Thanks in advance,
Loris.
Received on Sun Oct 10 16:00:36 2004