Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Mon, 04 Oct 1999 16:48:57 -0400
Judy Seigel wrote:
> ...
> Password protected sections:
count 'em.
33 sections do not require the password
32 sections are accessed by using the password once.
>
> One of the unprotected sections is the process formulas. The first line
> (and many of the rest) is absolutely wrong.
> The correct formulas are free, and no password, on Mike Ware's site.
Perhaps in your opinion. I am not totally in agreement with the process
equations on Mike Ware's site. The question of the process equations
came up several months ago and no one has yet provided an explanation.
I recall that I specifically requested for a chemist to help with
these. These may be updated some day. However, empirical studies were
made with results which support these equations. The work on AFO is
reported in Chapter 14. Work on FO had been done eight years ago but
not written up; some on-going studies address the FO.
>
> The process requires the evaporation and absorption of 116.9 gms of nitric
> acid. This must be dried in the dark. There is no safe way to accomplish
> this for the typical alt photo practitioner. ... Also, soaking up the
> acid in paper towels is not a great idea.
I just did it with standard safety equipment (all suggested in the
instructions). Paper towels soaks for four hours and were put into a
bucket of water with baking soda. Read my notes. I did not leave it
open all the time in the lab, only to exchange towels. I did place some
nails around to see if my vent system was removing things quick enough.
Not the greatest indicator but no corrosion occurred. When the towels
stop getting soaked, I use a dessicator with calcium oxide. One night I
vented it outside, but determined that the dessicator was the better
route.
I'll let Vicente field the safety and technical issues as I'm sure he
will.
>
> Read section 7 - this decanting takes 340 hours (with acid fumes present),
> but maybe 10-100 times longer. A centrifuge can help. I can just imagine
> this beaker of nitric acid being flung around in a darkroom.
A centrifuge can use closed containers designed for the purpose. But
anyway this is not part of the low cost approach. If one goes high tech
/ high cost much time can be saved.
>
> This procedure is referenced in Dick Stevens book. It's one of the
> procedures he does *not* recommend - the others are safer and easier.
>
> It also will not produce as good of a grade of FO as the other Stevens
> process. Even the RS procedure (free, on the B&S website, no password) is
> safer, easier, and will produce a more pure FO. Much more pure.
Vicente can respond to these as well.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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