From: Scott Wainer (smwbmp@starpower.net)
Date: 02/02/03-03:54:13 PM Z
Christina,
> > But the drill is to make *soft* positive so you can get through all
parts
> > of it easily for the negative. (See FotoDave, P-F #2.) If the positive
is
> > "punchy" it's much harder to get a full scale negative, especially
> > separation in shadows & highlights -- or so goes the conventional
wisdom.
Judy is right about "soft" positives; but why not make life much simpler and
use Liam' reversal process (P-F #'s 2, 3, & 4). I now use 5 pieces of film
for 4 negatives and I can adjust the density, by changing the "white light"
time, for whatever process I am going to use. A real plus is that you don't
have to worry as much about dust and you have less steps in the process.
> ... In fact, I tested adding a drop of 40% citric acid to cyanotype
> sensitizer (Ware's) to increase levels of tone and it really works! So
did
> giving a straight white vinegar first bath. Both were able to print in
> these bullet proof contrast negs...
The main reason for adding the citric acid was to allow Ware's formula to be
used with less than optimum papers (ones buffered with calcium carbonate).
It keeps the sensitizer acidic in an alkaline environment. The tonal
expansion is a great side-effect and I have found that it also works with
traditional formulas; though to a lesser extent. As for the vinegar bath, I
found that it gives a good increase in tonality with traditional formulas
but it tends to flatten out the shadows. Ware's formula does not seem to be
effected as much by vinegar as it does with a brief bath in hydrochloric
acid (4 drops per liter) after development. I haven't tried using a citric
acid after-bath yet but the premise should be the same.
Scott Wainer
smwbmp@starpower.net
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