joel lederer (lederer@netvision.net.il)
Mon, 18 Jan 1999 18:01:46 +0200
I have an idea and could use some advice.
I have been using the traditional dropper method in making pt/pl prints
and have found some limitations to this system. When making smallish
(4x5) prints I don't have very much control over the contrast because
the number of drops (of A and B) is so small. (6 drops of iron+ 6 drops
of metal)
My idea is to eliminate sol. B (ferric oxalate+K. chlorate) and replace
it with a concentrated solution of K. chlorate and add this to the
sensitizer with a micro pipette (I have seen ones which measure out in
1/100ths of a cc). The plan would be to make a solution strong enough so
that the highest contrast could be achieved without "watering" the
mixture down too much and not so strong that I loose the ability to
measure small amounts when a slight increase in contrast is needed.
Ultimately I would like to use a solution in which 1/10th of a cc would
be the highest contrast (for a 4x5 print) and 1/100th of a cc would be
the lowest contrast. For larger prints the amount could be multiplied.
I'm not sure where to begin with these experiments and have thought of
some questions. Perhaps I'm missing something obvious.., but here goes.
.
1)Are there any problems in making a concentrated K. chlorate solution
in water? e.g. solubility, keeping qualities, safety
2)What would be a good % solution(s) to begin with. The dropper method
uses a .6% solution but since this is mixed with F.O. , and because I'm
mathematically limited, well you get the picture.
3)How much of foreign solution could be added to the sensitizer w/o
running into problems?
4)Has anyone used this method or a similar one? (perhaps using a
different oxidizer)
I would be very happy to share my results with the people on the list
once I figure out where to start. If I can accurately measure out small
amounts of sensitizer with the micro pipette than making step tablet
prints shouldn't be a problem.
Thanks in advance
Joel Lederer- Tel Aviv
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